Giredestrant for Estrogen Receptor-Positive, HER2-Negative, Previously Treated Advanced Breast Cancer: Results From the Randomized, Phase II acelERA Breast Cancer Study

PURPOSE

To compare giredestrant and physician's choice of endocrine monotherapy (PCET) for estrogen receptor-positive, HER2-negative, advanced breast cancer (BC) in the phase II acelERA BC study (ClinicalTrials.gov identifier: NCT04576455).

METHODS

Post-/pre-/perimenopausal women, or men, age 18 years or older with measurable disease/evaluable bone lesions, whose disease progressed after 1-2 lines of systemic therapy (≤1 targeted, ≤1 chemotherapy regimen, prior fulvestrant allowed) were randomly assigned 1:1 to giredestrant (30 mg oral once daily) or fulvestrant/aromatase inhibitor per local guidelines (+luteinizing hormone-releasing hormone agonist in pre-/perimenopausal women, and men) until disease progression/unacceptable toxicity. Stratification was by visceral versus nonvisceral disease, prior cyclin-dependent kinase 4/6 inhibitor, and prior fulvestrant. The primary end point was investigator-assessed progression-free survival (INV-PFS).

RESULTS

At clinical cutoff (February 18, 2022; median follow-up: 7.9 months; N = 303), the INV-PFS hazard ratio (HR) was 0.81 (95% CI, 0.60 to 1.10; P = .1757). In the prespecified secondary end point analysis of INV-PFS by ESR1 mutation (m) status in circulating tumor DNA-evaluable patients (n = 232), the HR in patients with a detectable ESR1m (n = 90) was 0.60 (95% CI, 0.35 to 1.03) versus 0.88 (95% CI, 0.54 to 1.42) in patients with no ESR1m detected (n = 142). Related grade 3-4 adverse events (AEs), serious AEs, and discontinuations due to AEs were balanced across arms.

CONCLUSION

Although the acelERA BC study did not reach statistical significance for its primary INV-PFS end point, there was a consistent treatment effect with giredestrant across most key subgroups and a trend toward favorable benefit among patients with ESR1-mutated tumors. Giredestrant was well tolerated, with a safety profile comparable to PCET and consistent with known endocrine therapy risks. Overall, these data support the continued investigation of giredestrant in other studies.

Ribociclib plus Endocrine Therapy in Early Breast Cancer

BACKGROUND

Ribociclib has been shown to have a significant overall survival benefit in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer is unclear.

METHODS

In this international, open-label, randomized, phase 3 trial, we randomly assigned patients with HR-positive, HER2-negative early breast cancer in a 1:1 ratio to receive ribociclib (at a dose of 400 mg per day for 3 weeks, followed by 1 week off, for 3 years) plus a nonsteroidal aromatase inhibitor (NSAI; letrozole at a dose of 2.5 mg per day or anastrozole at a dose of 1 mg per day for ≥5 years) or an NSAI alone. Premenopausal women and men also received goserelin every 28 days. Eligible patients had anatomical stage II or III breast cancer. Here we report the results of a prespecified interim analysis of invasive disease-free survival, the primary end point; other efficacy and safety results are also reported. Invasive disease-free survival was evaluated with the use of the Kaplan-Meier method. The statistical comparison was made with the use of a stratified log-rank test, with a protocol-specified stopping boundary of a one-sided P-value threshold of 0.0128 for superior efficacy.

RESULTS

As of the data-cutoff date for this prespecified interim analysis (January 11, 2023), a total of 426 patients had had invasive disease, recurrence, or death. A significant invasive disease-free survival benefit was seen with ribociclib plus an NSAI as compared with an NSAI alone. At 3 years, invasive disease-free survival was 90.4% with ribociclib plus an NSAI and 87.1% with an NSAI alone (hazard ratio for invasive disease, recurrence, or death, 0.75; 95% confidence interval, 0.62 to 0.91; P = 0.003). Secondary end points - distant disease-free survival and recurrence-free survival - also favored ribociclib plus an NSAI. The 3-year regimen of ribociclib at a 400-mg starting dose plus an NSAI was not associated with any new safety signals.

CONCLUSIONS

Ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III early breast cancer. (Funded by Novartis; NATALEE ClinicalTrials.gov number, NCT03701334.).

TROPION-Breast01: Datopotamab deruxtecan vs chemotherapy in pre-treated inoperable or metastatic HR+/HER2- breast cancer

Improving the prognosis for patients with metastatic HR+/HER2- breast cancer remains an unmet need. Patients with tumors that have progressed on endocrine therapy and/or are not eligible for endocrine therapy had limited treatment options beyond chemotherapy. Antibody-drug conjugates are a novel and promising treatment class in this setting. Datopotamab deruxtecan (Dato-DXd) consists of a TROP2-directed humanized IgG1 monoclonal antibody attached via a serum-stable cleavable linker to a topoisomerase I inhibitor payload. TROPION-Breast01 is an ongoing phase III study that is evaluating the efficacy and safety of Dato-DXd compared with investigator's choice of standard-of-care chemotherapy in patients with inoperable or metastatic HR+/HER2- breast cancer who have received one or two prior lines of systemic chemotherapy in the inoperable or metastatic setting. Clinical Trial Registration: NCT05104866 (ClinicalTrials.gov).

Expression of Soluble Form of Aurora A as a Predictive Factor for Neoadjuvant Therapy in Breast Cancer Patients: A Single-Center Pilot Study

PURPOSE

To search for new predictive breast cancer biomarkers. We analyzed the serum concentrations of biomarkers involved in carcinogenesis, which can also be targeted by therapy.

METHODS

In a single-center prospective study, the serum levels of Aurora A, thymidine kinase 1, and human epidermal growth factor receptor type 3 (HER3) were determined in 119 women with BC before neoadjuvant treatment using ELISA kits.

RESULTS

The following clinical data were analyzed: age; TNM; the expression of ER, PGR, HER2, and Ki67; histological grade (G); and the response to neoadjuvant treatment (NAT) in the residual tumor burden classification (RCB). A complete pathological response (pCR) was achieved after NAT in 41 patients (34%). The highest proportion of the patients with a confirmed pCR was found for triple negative breast cancer (TNBC) (62.5%); non-luminal HER2-positive (52.6%) cancer subtypes (p = 0.0003); and in the G3 group (50%; p = 0.0078). The patients with higher levels of Aurora A were more likely to achieve pCR (p = 0.039). In the multivariate analysis, the serum Aurora A levels ≥ 4.75 ng/mL correlated with a higher rate of pCR (OR: 3.5; 95% CI: 1.2-10.1; p = 0.023).

CONCLUSIONS

We showed that in a biologically heterogeneous group of BC patients, the pretreatment serum Aurora A levels were of significant value in predicting the response to NAT.

Immediate breast reconstruction in breast cancer patients with the use of Serasynth and SeragynBR synthetic meshes. Single-oncological center experience, analysis of complications

<br><b>Introduction:</b> The use of meshes in mastectomies with immediate breast reconstruction (IBR) has become the gold standard.</br> <br><b>Aim:</b> The use of meshes in mastectomies with immediate breast reconstruction (IBR) has become a gold standard. The purpose of the study was to analyze the complications and own experience with the use of Serasynth fully absorbable and SeragynBR partially absorbable synthetic meshes.</br> <br><b>Material and methods:</b> In the period from December 2017 to July 2020, 118 IBR were performed in the Author's Department with the use of SeragynBR and Serasynth meshes in 93 patients operated for breast cancer. 78 Serasynth meshes (Group 1) and 40 SeragynBR meshes (Group 2) were implanted.</br> <br><b>Results:</b> The most common complication was persistent seroma collection, which was reported in 17.9% of cases in Group 1 and 25% in Group 2. Skin inflammation was reported in 7.6% and 17.5%, while infections in 2.5% and 5% of the operated breasts in Group 1 and Group 2. Reoperation was required in 5.1% and 5% of the patients in Group 1 and Group 2. The percentage of complications was lower when Serasynth rather than Seragyn BR meshes were implanted. The frequent incidence of the seroma collection did not contribute in any significant way to serious complications such as removal of mesh/implant or infection. The complications, which developed following the implantation of both mesh types, were similar to those presented in other publications concerning mastectomy with IBR with the use of synthetic meshes. The percentage of implant losses/explanations in the discussed groups was lower than that reported in the literature.</br> <br><b>Conclusion:</b> Despite the complications, both types of meshes can be considered as safe additions to reconstructive breast surgeries.</br> <br><b>Level of Evidence:</b> Level III.</br>.

Prognostic value of coronary atherosclerosis and CAC score for the risk of chemotherapy-related cardiac dysfunction (CTRCD): The protocol of ANTEC study

BACKGROUND

Cardiological complications of oncological treatment, including the most serious one, heart failure, constitute a significant and still unsolved clinical problem. A history of dyslipidemia and complications of atherosclerosis, including coronary artery disease, are established risk factors for cardiotoxicity in cancer patients. In recent years, a protective effect of statin treatment on the development of heart failure in cancer patients has been observed. This protocol describes a study aiming to assess the prognostic value of coronary atherosclerosis burden and the CAC score on the onset of cardiac dysfunction associated with cancer therapy.

METHODS

ANTEC (Atherosclerosis iN chemoTherapy-rElated Cardiotoxicity) is a single-site, prospective, observational study to evaluate the influence of the coronary atherosclerosis and CAC score assessed by computed tomography on the development of left ventricular systolic dysfunction in cancer patients with at least moderate cardiotoxicity risk. A group of 80 patients diagnosed with cancer prior to high-dose anthracycline chemotherapy (doxorubicin ≥ 240 mg / m2 body weight or epirubicin ≥ 600 mg / m2 body weight), without a history of heart failure and coronary artery disease, will be included in the study. Patient follow-up is planned for 12 months. In all patients, coronary computed tomographic angiography (CCTA) will be performed once at the beginning of the study. The primary endpoint is the onset of cancer therapy-related cardiovascular toxicity, defined as mild, moderate, severe and very severe according to ESC 2022 Cardio-oncology guidelines. During follow up, echocardiography with GLS assessment will be performed every three months. Additionally, new biomarkers of atherosclerosis (IL-6, MPO, TNF-alpha) will be measured every 6 months. The study registration identifier on clinicaltrials.gov is NCT05118178.

CLINICAL TRIALS REGISTRY

This study is listed on cinicaltrials.gov with identifier NCT05118178.

Abstract GS3-02: GS3-02 Camizestrant, a next generation oral SERD vs fulvestrant in post-menopausal women with advanced ER-positive HER2-negative breast cancer: Results of the randomized, multi-dose Phase 2 SERENA-2 trial

Background Camizestrant (C), a next-generation oral selective estrogen receptor (ER) antagonist and degrader (ngSERD) has shown promising clinical activity in ER+ breast cancer (BC) in the Phase 1 SERENA-1 study1,2 with a dose-dependent safety profile. The Phase 2 randomized SERENA-2 study (NCT04214288) initially assessed three doses of C vs fulvestrant (F) in post-menopausal women with ER+ HER2˗ BC with disease recurrence or progression after ≤1 endocrine therapy (ET) in the advanced setting.

Methods SERENA-2 evaluated efficacy and safety of C 75, 150 or 300 mg monotherapy QD vs F (per label). Eligible patients were randomized 1:1:1:1. The Primary objective was to determine clinical efficacy of C vs F by investigator-assessed progression-free survival (PFS). Secondary endpoints included objective response rate, response duration, clinical benefit rate at 24 weeks, overall survival and safety. Patients had no prior F or oral SERD and ≤1 ET and ≤1 chemotherapy (CTX) in the advanced setting. To assess the impact of prior CDK4/6 inhibitor (CDK4/6i) treatment, randomization was stratified so that 50% of patients had prior CDK4/6i. Planned enrolment of 288 patients began in April 2020. The C 300 arm was closed after 20 patients were enrolled, changing target enrolment to 236. By August 2021, 240 patients had been randomized. Primary analysis was triggered when 108 progression events (75% maturity) had occurred in the best performing pair (C vs F) in August 2022. Efficacy analyses compared C 75 and 150 mg doses with F, with no formal analyses of C 300 vs F. 108 events for pairwise comparison vs F gave 86% power at the 2-sided 10% significance level. Primary analyses used a Cox proportional hazards model to compare PFS, adjusting for prior CDK4/6i and lung/liver metastases. ESR1 mutations (ESR1m) were detected in plasma samples using next-generation sequencing.

Results 119/240 (49.6%) patients had had prior CDK4/6i therapy. At baseline, 88 (36.7%) patients had detectable ESR1m and 140 (58.3%) had lung/liver metastases. Prior CTX or ET rates in the advanced setting were 19.2 and 65.4%.

Treatment-emergent adverse events (AEs) (grade ≥3) occurred in 77.0 (12.2), 90.4 (21.9) and 68.5 (13.7) % of patients in the C 75, C 150 and F arms. AEs leading to treatment discontinuation occurred in 2.7, 0 and 0% of patients in the C 75, C 150 and F arms. The most common AEs considered by the investigator to be causally related to study drug were photopsia (18.4%) and (sinus) bradycardia (13.6%) – all were grade 1 or 2. Hot flush (2.7%) and myalgia (2.7%) were the most common AEs related to F.

Conclusions SERENA-2 is the first Phase 2 trial investigating multiple dose levels of an ngSERD vs F in post-menopausal women with advanced ER+ HER2˗ BC with disease recurrence or progression after ≤1 ET in the advanced setting. C at both 75 and 150 mg dose levels showed a statistically significant and clinically meaningful benefit in PFS vs F in the overall study population, and was well tolerated. The results of SERENA-2 support the further development of C in ER+ HER2- BC.

Acknowledgements

AstraZeneca sponsored this trial and funded medical writing support from Helen Heffron (InterComm International).

References

1. Baird R, Oliveira M, Ciruelos Gil EM, et al. SABCS 2020 Virtual Meeting. Abstract PS11-05; 2. Oliveira M, Hamilton EP, Incorvati J et al. ASCO 2022 Annual Meeting, Chicago, IL, USA. Abstract 1032.

Abstract GS3-04: GS3-04 Capivasertib and fulvestrant for patients with aromatase inhibitor-resistant hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer: results from the Phase III CAPItello-291 trial

Background: AKT pathway activation has been implicated in the development of endocrine therapy resistance in hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2–) advanced breast cancer (ABC). In the Phase II, placebo (PBO)-controlled FAKTION trial, the addition of the pan-AKT inhibitor capivasertib to fulvestrant significantly improved progression-free survival (PFS) and overall survival in postmenopausal women with aromatase inhibitor (AI)-resistant HR+/HER2– ABC. The Phase III, randomized, double-blind, PBO-controlled CAPItello-291 trial (NCT04305496) investigated the efficacy and safety of capivasertib + fulvestrant in patients with AI-resistant HR+/HER2– ABC. Methods: Eligible pre/peri or postmenopausal women or men with HR+/HER2– ABC that had recurred or progressed on or after AI therapy with or without a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor were randomized 1:1 to receive fulvestrant (per standard dosing schedule) with either PBO or capivasertib (400 mg twice daily; 4 days on, 3 days off). Randomization was stratified by the presence of liver metastases, prior use of CDK4/6 inhibitors, and geographic location. AKT pathway alteration status (at least one qualifying PIK3CA, AKT1, or PTEN alteration) was determined using next-generation sequencing in tumor tissue. The dual primary endpoint was investigator-assessed PFS in the overall population and in patients with AKT pathway-altered tumors. Results: A total of 708 patients were randomized: 355 to capivasertib + fulvestrant and 353 to PBO + fulvestrant. Overall, 41% of patients had AKT pathway-altered tumors (48% [n=289/602] of patients with tumor sequencing results), 22% were pre/perimenopausal and 77% postmenopausal, with 1% male. Prior therapy for advanced disease included: 87% of patients with ≥1 line of prior treatment, 69% with a prior CDK4/6 inhibitor, and 18% with prior chemotherapy. Demographic and baseline characteristics were broadly balanced between the overall and altered populations and by treatment groups. At primary analysis (data cut-off Aug 15, 2022), 551 and 236 PFS events had occurred in the overall and pathway-altered populations, respectively. Overall, the median PFS was 7.2 months with capivasertib + fulvestrant and 3.6 months with PBO + fulvestrant (hazard ratio [HR] 0.60; 95% confidence interval [CI] 0.51–0.71; p&lt;0.001). In patients with AKT pathway-altered tumors, median PFS was 7.3 months with capivasertib + fulvestrant and 3.1 months with PBO + fulvestrant (HR 0.50; 95% CI 0.38–0.65; p&lt;0.001). The objective response rate in patients with measurable disease was 22.9% for capivasertib + fulvestrant vs 12.2% for PBO + fulvestrant overall and 28.8% vs 9.7% in the AKT pathway-altered population. The most frequent all-grade adverse events (AEs) with capivasertib + fulvestrant were diarrhea (72.4% vs 20.0% PBO + fulvestrant arm), rash (group term of rash, rash macular, rash maculo-papular, rash papular, rash pruritic; 38.0% vs 7.1%) and nausea (34.6% vs 15.4%). The most frequently reported grade ≥3 AEs were rash (group term; 12.1% vs 0.3%), diarrhea (9.3% vs 0.3%), and hyperglycemia (2.3% vs 0.3%); grade ≥3 stomatitis was 2.0% vs 0%. AEs leading to discontinuation of capivasertib/placebo were reported in 13.0% and 2.3% of patients, respectively. Conclusions: Capivasertib + fulvestrant significantly improved PFS compared to fulvestrant alone in the overall population, and in patients with AKT pathway-altered tumors, and may become a future treatment option in this setting. The safety profile of capivasertib + fulvestrant was generally manageable and consistent with prior data. Funding: CAPItello-291 is sponsored by AstraZeneca. Editorial acknowledgment: AstraZeneca-funded medical writing support was provided by Suzanne Patel, Ph.D., from BOLDSCIENCE Inc. Capivasertib was discovered by AstraZeneca subsequent to a collaboration with Astex Therapeutics (and its collaboration with the Institute of Cancer Research and Cancer Research Technology Limited).

Citation Format: Nicholas Turner, Mafalda Oliveira, Sacha J. Howell, Florence Dalenc, Javier Cortés, Henry Gomez, Xichun Hu, Komal Jhaveri, Sibylle Loibl, Serafin Morales Murillo, Zbigniew Nowecki, Meena Okera, Yeon H. Park, Masakazu Toi, Lyudmila Zhukova, Chris Yan, Gaia Schiavon, Andrew Foxley, Hope Rugo. GS3-04 Capivasertib and fulvestrant for patients with aromatase inhibitor-resistant hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer: results from the Phase III CAPItello-291 trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS3-04.

Abstract PD11-09: PD11-09 Datopotamab deruxtecan (Dato-DXd) + durvalumab (D) as first-line (1L) treatment for unresectable locally advanced/metastatic triple-negative breast cancer (a/mTNBC): updated results from BEGONIA, a phase 1b/2 study

Background: Patients with a/mTNBC have limited treatment options and a poor prognosis (objective response rate [ORR] of 37%, median duration of response 6.5 months, median overall survival 15.5 months for 1L chemotherapy [Rugo, et al. Ann Oncol. 2021 LBA16]). Combining checkpoint inhibitors with 1L chemotherapy modestly improves outcomes but only in PD-L1–positive a/mTNBC, emphasizing a critical unmet need for patients with PD-L1–negative disease and for further improving outcomes in PD-L1–positive disease. BEGONIA (NCT03742102) is an ongoing 2-part, open-label platform study, evaluating safety and efficacy of D, an anti–PD-L1 antibody, combined with other novel therapies in 1L a/mTNBC, including Dato-DXd, an antibody-drug conjugate consisting of a humanized anti-TROP2 antibody covalently linked to a highly potent topoisomerase I inhibitor payload via a stable, tumor-selective, tetrapeptide-based cleavable linker. Early data from BEGONIA of D in combination with Dato-DXd showed promising responses. Here, we report updated results of Dato-DXd + D. Methods: Patients with unresectable a/mTNBC eligible for 1L treatment were enrolled, regardless of PD-L1 or TROP2 status, and received intravenous Dato-DXd 6 mg/kg + D 1120 mg every 3 weeks until progression or unacceptable toxicity. PD-L1, assessed using the VENTANA PD-L1 (SP263) Assay, was defined as high if ≥ 5% of the tumor area was populated by PD-L1–expressing tumor or immune cells. Primary endpoints were safety and tolerability. Secondary endpoints included investigator-assessed ORR (RECIST v1.1) and duration of response. Patients included in the efficacy analysis had ≥ 2 on-treatment disease assessments, progressed, died, or withdrew from the study. Results: As of April 8, 2022, 47 patients received Dato-DXd + D (39 ongoing) and 33 of those were included in the efficacy analysis. Median (range) follow-up was 7.5 (0–11) months. Patient age was a median of 51 years, 57% received prior treatment for early stage TNBC, and 60% had visceral metastases at baseline. Confirmed ORR was 26/33 (79%; 95% CI, 61–91); 2/33 patients (6%) had a complete response and 24/33 (73%) had a partial response. Confirmed response was irrespective of PD-L1 expression (PD-L1 high ORR, 4/5 [80%]; PD-L1 low, 16/21 [76%]; PD-L1 missing, 6/7 [86%] patients). Median duration of response was not reached; 100% of patients with a complete or partial response remained in response at 6 month follow-up, and 96% had an ongoing response at data cutoff. Adverse events (AEs) were manageable and consistent with the known safety profiles of each agent, with treatment-related AEs occurring in 41 patients (87%), any Grade 3/4 AEs in 17 patients (36%), and any serious AEs in 7 patients (15%). The most common all-Grade AEs were gastrointestinal (nausea in 26 patients [55%] and stomatitis in 24 patients [51%]). A low rate of diarrhea was reported (6 patients [13%], all Grade 1 or 2); 4 patients had anemia and 1 had neutropenia. There were no cases of interstitial lung disease/pneumonitis or thrombocytopenia. Nine patients (19%) and 11 patients (23%) underwent Dato-DXd dose reduction and delay, respectively; 14 (30%) had D dose delay. Treatment was discontinued due to an AE for 3 patients (6%). There were no deaths due to treatment-related AEs. Conclusions: In this updated analysis with additional patients and longer follow-up, the combination of Dato-DXd + D in 1L a/mTNBC demonstrated a manageable safety profile and compelling high response rates with promising durability. Although subgroups were small, responses occurred irrespective of PD-L1 expression. Further investigation of this treatment combination is warranted. Analysis of translational data is ongoing. Funding: AstraZeneca/Daiichi Sankyo

Citation Format: Peter Schmid, Piotr Wysocki, Cynthia Ma, Yeon H. Park, Ricardo Fernandes, Simon Lord, Richard D. Baird, Catherine Prady, Kyung Hae Jung, Jamil Asselah, Robert Huisden, Ross Stewart, Petra Vuković, Ana T. Nunes, Zbigniew Nowecki. PD11-09 Datopotamab deruxtecan (Dato-DXd) + durvalumab (D) as first-line (1L) treatment for unresectable locally advanced/metastatic triple-negative breast cancer (a/mTNBC): updated results from BEGONIA, a phase 1b/2 study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD11-09.

Abstract P1-23-03: Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland

Background: Male breast cancer is a rare disease accounting for less than 1% of all breast cancer diagnoses worldwide. Male breast cancer is not very well understood. Prospective data in the management of male breast cancer are lacking and majority of treatment strategies are adopted from the established guidelines for breast cancer in women. The understanding of biology, clinical presentation, genetics, and management of MBC is evolving but there still remains a large knowledge gap due to the rarity of this disease.Patients and methods: The aim of this retrospective study is to analyze the epidemiologic, clinical and therapeutic problems with this disease and to compare some cancer aspects between male and female in 67 cases collected at Maria Sklodowska Curie National Research Institute of Oncology in Warsaw between 05.2011 and 02.2021. Patients with a primary diagnosis of breast cancer were identified in the our database.Results: The median age was 65 years (range 22-93 years). Family history was present in 15 (22%) men and in as 17 pts (25%) other cancer were diagnosed (prostate cancer, melanoma, Hodgkin lymphoma, NET, thyroid cancer). Early, locally advanced, and metastatic disease were seen in 44 (65%), 9 (14%), and 14 (21%) men, respectively. Majority (59, 88%) of men had invasive ductal carcinoma histology. In radically treated 44 men, neoadjuvant chemotherapy was given to 20 (29%) patients with pCR in 1 (1.5%) and neoadjuvant hormonotherapy (tamoxifen) in 5 (7.5%) of pts. Estrogen receptor, PR, and human epidermal growth factor receptor 2/neu positive were seen in 62 (92.5%), 60 (89.5%), and 15 (22%) patients, respectively. Triple negative breast cancer were diagnosed in 4 (6%) pts. During the follow-up period locoregional recurrence occurred in 1 (1.5%) and distant metastasis in 15 (22%) men, respectively. Bone was the most representative site of metastases (20, 69%). In contrast to women with breast cancer, who have mainly osteolytic metastases (75-80%), our analysis found that men were predominantly osteoblastic lesions (10, 50% pts with bone mts). There was 31 cases of death (46%). Death was usually due breast cancer progression (29, 43%).Conclusion: This analysis found that men with breast cancer had a higher risk of second primaries cancer. Bone was the most representative site of metastases, but they are mainly osteoblastic lesions.

Citation Format: Agnieszka Irena Jagiello-Gruszfeld, Pawel Winter, Rafal Wojcik, Michal Kunkiel, Renata Sienkiewicz, Roman Dubianski, Anna Majstrak-Hulewska, Zbigniew Nowecki. Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-23-03.

Abstract GS1-07: Adjuvant palbociclib in HR+/HER2- early breast cancer: Final results from 5,760 patients in the randomized phase III PALLAS trial

Background Advances in the multidisciplinary care of hormone-receptor positive (HR+) early breast cancer (eBC) have markedly improved clinical outcomes: however, disease recurrence may still occur, particularly in patients (pts) with moderate or high-risk cancers at the time of diagnosis. The use of CDK4/6 inhibitors (CDK4/6i) combined with endocrine therapy (ET) is a standard of care for advanced breast cancer, supporting the rationale to study CDK4/6i in the eBC setting. Here we present the final protocol-planned analyses of the global phase III PALLAS trial investigating whether the addition of the CDK4/6i palbociclib (P) to adjuvant ET improves outcomes over ET alone for HR+/HER2- eBC. Methods PALLAS (PALbociclib CoLlaborative Adjuvant Study, NCT02513394) is a randomized phase III open-label trial in which pts with stage II-III HR+/HER2- eBC were randomized to receive either 2 years of P with adjuvant ET (P+ET) or ET alone. The primary endpoint is invasive disease-free survival (iDFS); secondary endpoints include distant recurrence-free survival (DRFS), locoregional recurrence-free survival (LRRFS), overall survival (OS), and safety. Mandatory biospecimen collection has supported the creation of an expansive translational science program, and long-term follow-up is planned. Revised sample size calculations required recruitment of 5600 pts in order to detect a 25% iDFS improvement in patients receiving P+ET with 85% power; this final protocol-planned analysis was planned after 469 iDFS events. Results From September 1, 2015 to November 30, 2018, 5,761 pts (median age 52 years, range 22-90) were randomized in 406 centers in 21 countries worldwide. 1,014 (17.6%) had stage IIA disease (capped) and 4,728 (82.1%) stages IIB/III. 4,754 (82.5%) had received prior (neo)adjuvant chemotherapy. After a protocol-planned 2nd interim analysis in May 2020 crossed the futility threshold, 349 P+ET pts still on active treatment stopped P and were transferred to follow-up. At the time of final analysis cutoff date (November 20, 2020), after a median follow-up of 31 months and 516 events recorded, iDFS was similar between the two arms, with 3-year iDFS of 89.3% (95% CI: 87.8-90.6%) for Palbo+ET, and 89.4% (88.0-90.7%) for ET alone (hazard ratio 0.96, 95% CI: 0.81-1.14). There was no statistically significant difference in secondary outcome endpoints. Subgroup analyses revealed no significant interactions between treatment effect and other factors (including risk category). The safety profile of P was as expected, with grade 3 or 4 neutropenia the most common side effect (safety population: 1759/2841 [61.9%] vs 11/2902 [0.4%]). Overall 42% of pts. discontinued P prior to the planned 2-year duration, 28.2% of Palbo+ET pts discontinued therapy due to adverse events, without an observed impact on survival outcomes. Conclusions Now with the full number of events, this analysis of the PALLAS trial shows that the addition of 2 years of P to ongoing adjuvant ET did not improve survival endpoints for pts with stage II-III HR+/HER2- eBC. Whether P is beneficial in the adjuvant setting for certain sub-groups of pts will be further evaluated with longer-term follow-up and by the ongoing translational science program. Support: ABCSG; AFT; Pfizer; ClinicalTrials.gov Identifier: NCT02513394; https://www.abcsg.org; https://acknowledgments.alliancefound.org

Citation Format: Michael Gnant, Amylou C Dueck, Sophie Frantal, Miguel Martin, Hal Burstein, Richard Greil, Peter Fox, Antonio C Wolff, Arlene Chan, Eric Winer, Christian Singer, Kathy Miller, Marco Colleoni, Michelle Naughton, Gabor Rubovszky, Judith Bliss, Ingrid A Mayer, Guenther G Steger, Zbigniew Nowecki, Olwen Hahn, Norman Wolmark, Hope Rugo, Georg Pfeiler, Hannes Fohler, Otto Metzger, Céline Schurmans, Kathy P Theall, Dongrui R Lu, Kathleen Tenner, Christian Fesl, Angela DeMichele*, Erica L Mayer, *shared last authorship. Adjuvant palbociclib in HR+/HER2- early breast cancer: Final results from 5,760 patients in the randomized phase III PALLAS trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS1-07.

Abstract GS1-02: Final results of KEYNOTE-355: Randomized, double-blind, phase 3 study of pembrolizumab + chemotherapy vs placebo + chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer

Background: In the phase 3 KEYNOTE-355 trial (NCT02819518), pembrolizumab (pembro) combined with chemotherapy (chemo) showed statistically significant improvements in OS and PFS compared to placebo + chemo in patients with previously untreated locally recurrent inoperable or metastatic TNBC whose tumors expressed PD-L1 with a combined positive score (CPS) ≥10. There were no statistically significant differences between treatment groups in the CPS ≥1 population, and statistical significance was not tested in the ITT population due to the prespecified testing strategy. Here, we compare outcomes in subgroups of patients by additional CPS cut-offs to the primary results of KEYNOTE-355. Methods: 847 patients with measurable disease per RECIST v1.1, ECOG PS 0-1, and ≥6 month disease-free interval were randomized 2:1 to pembro + chemo (nab-paclitaxel 100 mg/m2 days 1, 8, and 15 every 28 days; paclitaxel 90 mg/m2 days 1, 8, and 15 every 28 days; or gemcitabine 1000 mg/m2 + carboplatin AUC 2 days 1 and 8 every 21 days) or placebo + chemo for up to 35 administrations of pembro/placebo or until progression/intolerable toxicity. Patients were stratified by chemo type (taxane or gemcitabine-carboplatin), PD-L1 status (CPS ≥1 or &lt;1), and prior neoadjuvant/adjuvant treatment with same-class chemo (yes or no). Dual primary endpoints were OS and PFS (RECIST v1.1, blinded independent central review) in patients with PD-L1-positive tumors (CPS ≥10 and ≥1) and in the ITT population. Hazard ratios (HRs) and 95% CIs in the additional CPS subgroups were based on an unstratified Cox model. Results: At the time of the final analysis (data cutoff, June 15, 2021), the median time from randomization to data cutoff was 44 months. Baseline characteristics of the CPS 1-9, 10-19, and ≥20 subgroups were generally similar to those of the ITT population. In the primary analyses, the HRs (95% CI) for OS were 0.73 (0.55-0.95) in the CPS ≥10 subgroup, 0.86 (0.72-1.04) in the CPS ≥1 subgroup, and 0.89 (0.76-1.05) in the ITT population; HRs (95% CI) for PFS were 0.66 (0.50-0.88), 0.75 (0.62-0.91), and 0.82 (0.70-0.98), respectively. Efficacy data are presented for the additional CPS subgroups in the Table. For OS, results in the CPS 1-9 subgroup showed comparable efficacy for pembro + chemo and placebo + chemo; however, results in the CPS 10-19 and CPS ≥20 subgroups showed a similar treatment benefit with the addition of pembro. Results for PFS were generally consistent with those observed for OS.

Conclusions: These results provide support that CPS ≥10 is a reasonable cut-off to define the population of patients with metastatic TNBC expected to derive treatment benefit from pembro + chemo.

Table. Efficacy in additional subgroups of patients by PD-L1 CPSCPS subgroupTreatmentMedian OS, mo (95% CI)OS HR (95% CI)*Median PFS, mo (95% CI)PFS HR (95% CI)*1-9†Pembro + Chemo. n = 20513.9. (12.2-16.6)1.09 (0.85-1.40)5.7. (5.4-7.4)0.85 (0.65-1.11)Placebo + Chemo n = 10815.5. (12.4-17.6)5.6. (5.3-7.6)10-19†Pembro + Chemo. n = 8020.3. (15.2-29.0)0.71 (0.46-1.09)9.9. (7.4-11.8)0.70 (0.44-1.09)Placebo + Chemo n = 3917.6. (10.3-25.8)7.6. (5.3-9.7)≥20‡Pembro + Chemo. n = 14024.0 (19.0-28.3)0.72 (0.51-1.01)9.2 (7.6-11.8)0.62 (0.44-0.88)Placebo + Chemo n = 6415.6. (12.3-20.8)5.4 (3.9-7.2)*Analyses based on an unstratified Cox model. †Post-hoc analyses. ‡Prespecified exploratory analyses.

Citation Format: Javier Cortes, David W. Cescon, Hope S. Rugo, Zbigniew Nowecki, Seock-Ah Im, Mastura Md Yusof, Carlos Gallardo, Oleg Lipatov, Carlos Henrique Barrios, Jose Perez-Garcia, Hiroji Iwata, Norikazu Masuda, Marco Torregroza Otero, Erhan Gokmen, Sherene Loi, Zifang Guo, Xuan Zhou, Vassiliki Karantza, Wilbur Pan, Peter Schmid. Final results of KEYNOTE-355: Randomized, double-blind, phase 3 study of pembrolizumab + chemotherapy vs placebo + chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS1-02.

Abstract PD10-03: BEGONIA: Phase 1b/2 study of durvalumab (D) combinations in locally advanced/metastatic triple-negative breast cancer (TNBC): Results from Arm 1 D + paclitaxel (P), Arm 2 D+P + capivasertib (C), and Arm 5 D+P + oleclumab (O)

Background: Chemotherapy, together with immune checkpoint inhibitors, improves outcomes vs chemotherapy alone for patients (pts) with metastatic (m)TNBC PD-L1+ disease. Most of these pts progress within a year. In a previous study, D (anti-PD-L1) combined with chemotherapy enhanced antitumor immune responses in early TNBC (Loibl. Ann Oncol 2019). In TNBC, activation of the PI3K/AKT/PTEN pathway and high CD73 expression are common. BEGONIA is an ongoing 2-part, multicenter, multi-arm, open-label platform study, evaluating safety and efficacy of D or D+P combined with novel therapies as first-line treatment for mTNBC (NCT03742102). Preliminary results from 2 arms were presented at ASCO 2021 (Abstract #1023). Here, we report results from Arm 1 D+P, Arm 2 D+P+C, and Arm 5 D+P+O. C is an oral, selective, ATP-competitive catalytic inhibitor of all 3 AKT isoforms, and O is a mAb targeting CD73. Methods: Eligible pts had untreated, unresectable, locally advanced or metastatic TNBC. In Arms 1 and 5, pts received D 1500 mg IV Q4W + P 90 mg/m2 IV day (d)1, d8, d15 of every cycle. Pts in Arm 5 also received O 3000 mg IV on d1 and d15 for the first 2 cycles, then Q4W. In Arm 2, pts received D 1500 mg IV Q4W + P 80/90 mg/m2 IV in 4-week cycles (d1, d8, d15, 1 week off) + C 400 mg BID in 4-week cycles (d2-5 × 3 weeks, 1 week off). Primary objectives were safety and tolerability. Secondary endpoints included objective response rate (ORR) and duration of response. Tumors were assessed Q8W per RECIST v1.1. The first 6 pts treated in Arms 2 and 5 were evaluated for dose-limiting toxicities (DLTs), with additional pts enrolled if treatment was tolerated. PD-L1 expression was assessed retrospectively. Previously presented data from Arm 1 D+P, are included for reference (Schmid. ASCO 2021, #1023). Results: In Arm 2 (data cutoff Mar 2021), 30 pts received D+P+C (15 P[80], 15 P[90]; total 13 ongoing); 2 pts (6.7%) discontinued all treatment due to AEs. The rates of dose delays were 13 pts (43%) for D and 15 (50%) for P; dose interruptions were 1 (3%) for D, 12 (40%) for P, 15 (50%) for C; dose reductions were 12 (40%) for P and 14 (47%) for C. Treatment-related (tr)SAEs and G3/4 trAEs were experienced by 7 (23%) and 22 (73%) pts. In Arm 5 (data cutoff Sep 2020), 33 pts received D+P+O (14 ongoing); no pts discontinued due to AEs. The rates of dose delays were 13 pts (39%) for D, 10 (30%) for P, 10 (30%) for O; dose interruptions were 2 (6%) for D, 10 (30%) for P, 3 (9%) for O; and dose reductions were 12 (36%) for P. trSAEs and G3/4 trAEs were experienced by 1 (3%) and 5 (15%) pts. In both arms, there were no DLTs or deaths due to AEs. The Table presents follow-up time and efficacy outcomes for Arms 1, 2, and 5. Responses were observed regardless of PD-L1 expression. The potential value of mutations in the PI3K pathway and CD73 expression as predictive biomarkers will be discussed for Arms 2 and 5, respectively. Updated data for Arm 1 will be presented. Conclusions: The safety profiles of triplet combinations in Arms 2 and 5 were consistent with the individual agents; however, in Arm 2, there was a relatively high rate of G3/4 trAEs but a low discontinuation rate for AEs. Although BEGONIA was not designed to compare activity across arms and numbers were small, the ORR of each triplet therapy was numerically similar to D+P. Biomarker analysis may elucidate pts that benefit from the combination of C or O with D+P. Funding: AstraZeneca

Table. Efficacy outcomes in Arms 1, 2, and 5 of BEGONIAArm 1Arm 2Arm 5D+P N=23D+P(80)+C n=15D+P(90)+C n=15All D+P+C N=30D+P+O N=33Duration of follow-up at data cutoff, months, median (range)16.6 (8.5-19.8)6.7 (2-9)16.8 (6-21)8.2 (2-21)8.6 (4.1-14.6)Confirmed ORR, n (%)13 (56.5)8 (53.3)8 (53.3)16 (53.3)15 (45.5)95% CI34.5-76.826.6-78.726.6-78.7NC28.1-63.3CR, n10111PR12871514SD (Unconfirmed PR)7 (3)6 (2)4 (2)10 (4)13 (4)PD31345Percentage with ongoing response at data cutoff53.8%75.0%25.0%50.0%66.7%Arm 1 data cutoff was Sep 2020. C, capivasertib; CI, confidence interval; CR, complete response; D, durvalumab; NC, not calculable; O, oleclumab; ORR, objective response rate; P, paclitaxel; PD, progressive disease; PR, partial response; SD, stable disease.

Citation Format: Peter Schmid, Zbigniew Nowecki, Seock-Ah Im, Wei-Pang Chung, Simon Lord, Anne Armstrong, Cynthia X Ma, Robert Huisden, Ross Stewart, Rakesh Kumar, Gaia Schiavon, Hannah Dry, Ana Nunes, Kyung Hae Jung, Yeon Hee Park. BEGONIA: Phase 1b/2 study of durvalumab (D) combinations in locally advanced/metastatic triple-negative breast cancer (TNBC): Results from Arm 1 D + paclitaxel (P), Arm 2 D+P + capivasertib (C), and Arm 5 D+P + oleclumab (O) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD10-03.

Trastuzumab Emtansine Plus Pertuzumab Versus Taxane Plus Trastuzumab Plus Pertuzumab After Anthracycline for High-Risk Human Epidermal Growth Factor Receptor 2-Positive Early Breast Cancer: The Phase III KAITLIN Study

PURPOSE

We aimed to improve efficacy and reduce toxicity of high-risk human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC) treatment by replacing taxanes and trastuzumab with trastuzumab emtansine (T-DM1).

METHODS

The phase III KAITLIN study (NCT01966471) included adults with excised HER2-positive EBC (node-positive or node-negative, hormone receptor-negative, and tumor > 2.0 cm). Postsurgery, patients were randomly assigned 1:1 to anthracycline-based chemotherapy (three-four cycles) and then 18 cycles of T-DM1 plus pertuzumab (AC-KP) or taxane (three-four cycles) plus trastuzumab plus pertuzumab (AC-THP). Adjuvant radiotherapy/endocrine therapy was permitted. Coprimary end points were invasive disease-free survival (IDFS) in the intention-to-treat node-positive and overall populations with hierarchical testing.

RESULTS

The median follow-up was 57.1 months (interquartile range, 52.1-60.1 months) for AC-THP (n = 918) and 57.0 months (interquartile range, 52.1-59.8 months) for AC-KP (n = 928). There was no significant IDFS difference between arms in the node-positive (n = 1,658; stratified hazard ratio [HR], 0.97; 95% CI, 0.71 to 1.32) or overall population (n = 1846; stratified HR, 0.98; 95% CI, 0.72 to 1.32). In the overall population, the three-year IDFS was 94.2% (95% CI, 92.7 to 95.8) for AC-THP and 93.1% (95% CI, 91.4 to 94.7) for AC-KP. Treatment completion rates (ie, 18 cycles) were 88.4% for AC-THP and 65.0% for AC-KP (difference driven by T-DM1 discontinuation because of laboratory abnormalities [12.5%]). Similar rates of grade ≥ 3 (55.4% v 51.8%) and serious adverse events (23.3% v 21.4%) occurred with AC-THP and AC-KP, respectively. KP decreased clinically meaningful deterioration in global health status versus THP (stratified HR, 0.71; 95% CI, 0.62 to 0.80).

CONCLUSION

The primary end point was not met. Both arms achieved favorable IDFS. Trastuzumab plus pertuzumab plus chemotherapy remains the standard of care for high-risk HER2-positive EBC.

Adjuvant Palbociclib for Early Breast Cancer: The PALLAS Trial Results (ABCSG-42/AFT-05/BIG-14-03)

PURPOSE

Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor-positive breast cancer has not been confirmed.

PATIENTS AND METHODS

In the prospective, randomized, phase III PALLAS trial, patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer were randomly assigned to receive 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle) with adjuvant endocrine therapy or adjuvant endocrine therapy alone (for at least 5 years). The primary end point of the study was invasive disease-free survival (iDFS); secondary end points were invasive breast cancer-free survival, distant recurrence-free survival, locoregional cancer-free survival, and overall survival.

RESULTS

Among 5,796 patients enrolled at 406 centers in 21 countries worldwide over 3 years, 5,761 were included in the intention-to-treat population. At the final protocol-defined analysis, at a median follow-up of 31 months, iDFS events occurred in 253 of 2,884 (8.8%) patients who received palbociclib plus endocrine therapy and in 263 of 2,877 (9.1%) patients who received endocrine therapy alone, with similar results between the two treatment groups (iDFS at 4 years: 84.2% v 84.5%; hazard ratio, 0.96; CI, 0.81 to 1.14; P = .65). No significant differences were observed for secondary time-to-event end points, and subgroup analyses did not show any differences by subgroup. There were no new safety signals for palbociclib in this trial.

CONCLUSION

At this final analysis of the PALLAS trial, the addition of adjuvant palbociclib to standard endocrine therapy did not improve outcomes over endocrine therapy alone in patients with early hormone receptor-positive breast cancer.

Ipatasertib plus paclitaxel for PIK3CA/AKT1/PTEN-altered hormone receptor-positive HER2-negative advanced breast cancer: primary results from cohort B of the IPATunity130 randomized phase 3 trial

PURPOSE

PI3K/AKT pathway alterations are frequent in hormone receptor-positive (HR+) breast cancers. IPATunity130 Cohort B investigated ipatasertib-paclitaxel in PI3K pathway-mutant HR+ unresectable locally advanced/metastatic breast cancer (aBC).

METHODS

Cohort B of the randomized, double-blind, placebo-controlled, phase 3 IPATunity130 trial enrolled patients with HR+ HER2-negative PIK3CA/AKT1/PTEN-altered measurable aBC who were considered inappropriate for endocrine-based therapy (demonstrated insensitivity to endocrine therapy or visceral crisis) and were candidates for taxane monotherapy. Patients with prior chemotherapy for aBC or relapse < 1 year since (neo)adjuvant chemotherapy were ineligible. Patients were randomized 2:1 to ipatasertib (400 mg, days 1-21) or placebo, plus paclitaxel (80 mg/m², days 1, 8, 15), every 28 days until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS).

RESULTS

Overall, 146 patients were randomized to ipatasertib-paclitaxel and 76 to placebo-paclitaxel. In both arms, median investigator-assessed PFS was 9.3 months (hazard ratio, 1.00, 95% CI 0.71-1.40) and the objective response rate was 47%. Median paclitaxel duration was 6.9 versus 8.8 months in the ipatasertib-paclitaxel versus placebo-paclitaxel arms, respectively; median ipatasertib/placebo duration was 8.0 versus 9.1 months, respectively. The most common grade ≥ 3 adverse events were diarrhea (12% with ipatasertib-paclitaxel vs 1% with placebo-paclitaxel), neutrophil count decreased (9% vs 7%), neutropenia (8% vs 9%), peripheral neuropathy (7% vs 3%), peripheral sensory neuropathy (3% vs 5%) and hypertension (1% vs 5%).

CONCLUSION

Adding ipatasertib to paclitaxel did not improve efficacy in PIK3CA/AKT1/PTEN-altered HR+ HER2-negative aBC. The ipatasertib-paclitaxel safety profile was consistent with each agent's known adverse effects. Trial registration NCT03337724.

Final results from the PERUSE study of first-line pertuzumab plus trastuzumab plus a taxane for HER2-positive locally recurrent or metastatic breast cancer, with a multivariable approach to guide prognostication

BACKGROUND

The phase III CLinical Evaluation Of Pertuzumab And TRAstuzumab (CLEOPATRA) trial established the combination of pertuzumab, trastuzumab and docetaxel as standard first-line therapy for human epidermal growth factor receptor 2 (HER2)-positive locally recurrent/metastatic breast cancer (LR/mBC). The multicentre single-arm PERtUzumab global SafEty (PERUSE) study assessed the safety and efficacy of pertuzumab and trastuzumab combined with investigator-selected taxane in this setting.

PATIENTS AND METHODS

Eligible patients with inoperable HER2-positive LR/mBC and no prior systemic therapy for LR/mBC (except endocrine therapy) received docetaxel, paclitaxel or nab-paclitaxel with trastuzumab and pertuzumab until disease progression or unacceptable toxicity. The primary endpoint was safety. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). Prespecified subgroup analyses included subgroups according to taxane, hormone receptor (HR) status and prior trastuzumab. Exploratory univariable analyses identified potential prognostic factors; those that remained significant in multivariable analysis were used to analyse PFS and OS in subgroups with all, some or none of these factors.

RESULTS

Of 1436 treated patients, 588 (41%) initially received paclitaxel and 918 (64%) had HR-positive disease. The most common grade ≥3 adverse events were neutropenia (10%, mainly with docetaxel) and diarrhoea (8%). At the final analysis (median follow-up: 5.7 years), median PFS was 20.7 [95% confidence interval (CI) 18.9-23.1] months overall and was similar irrespective of HR status or taxane. Median OS was 65.3 (95% CI 60.9-70.9) months overall. OS was similar regardless of taxane backbone but was more favourable in patients with HR-positive than HR-negative LR/mBC. In exploratory analyses, trastuzumab-pretreated patients with visceral disease had the shortest median PFS (13.1 months) and OS (46.3 months).

CONCLUSIONS

Mature results from PERUSE show a safety and efficacy profile consistent with results from CLEOPATRA and median OS exceeding 5 years. Results suggest that paclitaxel is a valid alternative to docetaxel as backbone chemotherapy. Exploratory analyses suggest risk factors that could guide future trial design.

Adjuvant Olaparib for Patients with BRCA1- or BRCA2-Mutated Breast Cancer

BACKGROUND

Poly(adenosine diphosphate-ribose) polymerase inhibitors target cancers with defects in homologous recombination repair by synthetic lethality. New therapies are needed to reduce recurrence in patients with BRCA1 or BRCA2 germline mutation-associated early breast cancer.

METHODS

We conducted a phase 3, double-blind, randomized trial involving patients with human epidermal growth factor receptor 2 (HER2)-negative early breast cancer with BRCA1 or BRCA2 germline pathogenic or likely pathogenic variants and high-risk clinicopathological factors who had received local treatment and neoadjuvant or adjuvant chemotherapy. Patients were randomly assigned (in a 1:1 ratio) to 1 year of oral olaparib or placebo. The primary end point was invasive disease-free survival.

RESULTS

A total of 1836 patients underwent randomization. At a prespecified event-driven interim analysis with a median follow-up of 2.5 years, the 3-year invasive disease-free survival was 85.9% in the olaparib group and 77.1% in the placebo group (difference, 8.8 percentage points; 95% confidence interval [CI], 4.5 to 13.0; hazard ratio for invasive disease or death, 0.58; 99.5% CI, 0.41 to 0.82; P<0.001). The 3-year distant disease-free survival was 87.5% in the olaparib group and 80.4% in the placebo group (difference, 7.1 percentage points; 95% CI, 3.0 to 11.1; hazard ratio for distant disease or death, 0.57; 99.5% CI, 0.39 to 0.83; P<0.001). Olaparib was associated with fewer deaths than placebo (59 and 86, respectively) (hazard ratio, 0.68; 99% CI, 0.44 to 1.05; P = 0.02); however, the between-group difference was not significant at an interim-analysis boundary of a P value of less than 0.01. Safety data were consistent with known side effects of olaparib, with no excess serious adverse events or adverse events of special interest.

CONCLUSIONS

Among patients with high-risk, HER2-negative early breast cancer and germline BRCA1 or BRCA2 pathogenic or likely pathogenic variants, adjuvant olaparib after completion of local treatment and neoadjuvant or adjuvant chemotherapy was associated with significantly longer survival free of invasive or distant disease than was placebo. Olaparib had limited effects on global patient-reported quality of life. (Funded by the National Cancer Institute and AstraZeneca; OlympiA ClinicalTrials.gov number, NCT02032823.).

Trastuzumab biosimilar (Kanjinti) in breast cancer patients: One-center retrospective observational study

e13015

Background: The switch of anti-HER2 therapy from the reference drug Herceptin to a biosimilar has presented challenges to the clinics. Real world data on trastuzumab biosimilars are very limited or not available. In our clinic we perform observational retrospective study to confirm safety and efficacy Kanjinti. Methods: 195 patients (pts) with HER2-positive breast cancer were treated with Kanjinti from Jul.18. 2018 to Jan.29.2020. Cardiac events (↓LVEF) and other unexpected or serious adverse events were monitored in all pts. 34 pts received carboplatin, docetaxel pertuzumab and trastuzumab biosimilar in neoadjuvant setting, 99 received trastuzumab biosymilar in monotherapy or with other cytostatic drugs in neoadjuvant or adjuvant setting, and 62 received docetaxel, pertuzumab and Kanjinti in metastatic setting. Results: Pertuzumab was used in combination with Kanjinti in 49% of pts (32% in the 1st. line of palliative tretment and 17% in the neoadjuvant settings, respectively).Switching from Herceptin to Kanjinti was observed in 65% of MBC patients and 37% of EBC patients. Switching was done at a median of 4th cycle. 6 patients had a decline in LVEF. No other trastuzumab related adverse events was observed. Conclusions: The management of HER2 positive breast cancer in our clinic follows the international recommendations. This is the first real world safety data of Kanjinti from Poland. The 12-month follow-up treatment with Kanjinti an acceptable cardiac safety profile. In cases where there was a switch from Herceptin to Kanjinti or Kanjinti combined with pertuzumab, the safety profile was similar to that previously reported in other studies.

Oral etoposide in heavily pre-treated metastatic breast cancer: A retrospective study

e13070

Background: Patients with metastatic breast cancer can derive clinical benefit from several subsequent lines of chemotherapy. However, in heavily pre-treated patients, agents with clinical activity, a favourable side effects profile and a convenient administration modality are preferred. Oral etoposide may be an interesting treatment option in this group of patients. Methods: This was a retrospective observational study performed in single institution in 22 patients with MBC refractory to prior anthracycline, taxane, and capecitabine therapy. All patients were treated with oral etoposide at 50 mg/day on days 1-20. Treatment cycles were repeated every 28 days. Results: The median age were 53 years (42-68). The median number of previous chemotherapy lines was 5 (range 2-7). There were no complete or partial responses. Median PFS was 7 months. In 5 patients, the disease stabilized for over 12 months. Interestingly, etoposide activity was unrelated to the number of previous lines and type of metastatic involvement. Oral etoposide was well tolerated with only one patients discontinuing therapy due to toxicity. Conclusions: In real practice oral etoposide is a valuable and safe option for pre-treated metastatic breast cancer patients and might be considered in patients failing other approaches, but still suitable for chemotherapy.

Assessment of the treatment results in patients with breast cancer coexisting with pregnancy: A single-center observational study

e12566

Background: This study discusses the analysis of the prospectively collected material on pregnant patients treated for breast cancer at the Department of Breast Cancer and Reconstructive Surgery of the Maria Skłodowska-Curie National Oncology Institute - National Research Institute (until 2020: Oncology Center - Institute) in Warsaw, in the years 1995 - 2020. 84 patients were included into the final analysis and 72 children were assessed simultaneously. Methods: The paper summarizes information on the diagnosis and treatment of breast cancer during pregnancy, the course of pregnancy and childbirth and the birth parameters of children i.e. weight, length and Apgar score, as well as the dependencies between them, mainly the impact of some breast cancer, diagnosis and treatment process features on the newborns. The patietnt’s survavial - DFS ( disease free survival) and OS ( overall survival) - was also analyzed. The course of breast cancer diagnosis and treatment data were obtained from the patients’ medical documentation (medical records) and from information provided by the mothers during follow-up visits and read in the children's health books. In order to answer the research questions, statistical analyzes were conducted using the IBM SPSS Statistics 26 package. Results: In the analyzed period, the disease recurrence was recognized in 34 (40.5%) patients, and 24 (28.6%) patients died. The median disease-free survival (DFS) was 12.3 years (147.5 months), and the median overall survival (OS) was not reached during the follow-up period. The estimated 5-year survival rates for DFS and OS were 57.9% and 74.5% respectively, and for 10-year survival - 51.4% and 64.5%. The study showed a statistically significant relationship between the baseline clinical advancement and DFS. It has been also analyzed how the diagnosis, treatment and method of pregnancy termination changed in two time periods (1995-2012 and 2013-2020). There were no statistically significant differences in survival - both DFS and OS - between the group of patients treated before and after 2012. In the assessment of the impact of some factors on the birth children parameters (weight and length), statistically significant results were obtained for: pregnancy advancement at diagnosis, breast cancer stage at diagnosis, pregnancy advancement at the start of chemotherapy, the chemotherapy regimen (classic or dose-dense), the number of cycles of chemotherapy given during pregnancy, and the number of drugs used in supportive treatment. Conclusions: The entire analysis has become not only an insightful characteristic of the studied group, but also these results may be important in everyday clinical practice and may help to optimize the management of an extremely complex and difficult situation, which is the coexistence of pregnancy with a malignant disease that threatens the mother’s life.

BEGONIA: Phase 1b/2 study of durvalumab (D) combinations in locally advanced/metastatic triple-negative breast cancer (TNBC)—Initial results from arm 1, d+paclitaxel (P), and arm 6, d+trastuzumab deruxtecan (T-DXd)

1023

Background: Chemotherapy with immune checkpoint inhibitors can improve outcomes vs chemotherapy alone in patients (pts) with metastatic TNBC; however, many still have poor clinical outcomes. BEGONIA is an ongoing 2 part, multicenter, multiarm, open-label platform study evaluating safety and efficacy of D (anti–PD-L1)+P and D±P combined with novel therapies as first-line (1L) treatment for metastatic TNBC (NCT03742102). We report initial results from Part 1 of Arm 1, D+P, and Arm 6, D+T-DXd, an antibody-drug conjugate comprising an anti-HER2 antibody, tetrapeptide-based cleavable linker, and topoisomerase I inhibitor payload. Methods: Eligible pts had untreated unresectable locally advanced or metastatic TNBC. Pts with HER2-low–expressing tumors (IHC 2+/ISH–, IHC 1+/ISH–, or IHC 1+/ISH untested) per local testing were assigned to the D+T-DXd arm. Pts received D (1500 mg IV Q4W)+P (90 mg/m2 IV Day 1, 8, 15 Q4W) in Arm 1 and D (1120 mg IV)+T-DXd (5.4 mg/kg IV) Q3W in Arm 6, until progression or unacceptable toxicity. Primary objectives are safety and tolerability. Secondary endpoints include objective response rate (ORR), duration of response (DoR), and progression-free survival (PFS). Tumors were assessed Q8W (D+P) or Q6W (D+T-DXd). The first 6 pts treated with D+T-DXd were evaluated for dose-limiting toxicities (DLTs), with additional pts enrolled if D+T-DXd was tolerated. Study arms are noncomparable due to differing eligibility criteria, treatments, and data maturity. Results: Arm 1 D+P (data cutoff Sep 2020): 23 pts received D+P (7 ongoing); 2 discontinued D+P due to AEs. Median follow-up time was 16.6 (range 8.5–19.8) mos. Any Grade 3/4 AEs and SAEs were experienced by 10 (44%) and 1 (4%) pts, respectively. D dose was delayed for 7 (30%) pts. Confirmed ORR was 13/23 (57%) with 54% of those remaining in response at 12 mos (median DoR not reached). Median PFS was 7.3 (95% CI 5.4–13.8) mos in the D+P arm. Arm 6 D+T-DXd (data cutoff Nov 2020): 11 pts received D+T-DXd to date (all ongoing). Median follow-up time was 2.3 (0–6) mos. Any Grade 3/4 AEs and SAEs were experienced by 4 (36%) and 1 (9%) pts, respectively. Pts who received D+T-DXd had no DLTs and 1 had a Grade 1 troponin increase. D dose was delayed and T-DXd dose reduced for 2 (18%) pts each. Confirmed ORR was 4/4 (100%; only 4 pts had the opportunity to complete 2 on-treatment disease assessments) with all 4 remaining in response at data cutoff (median DoR not reached). Conclusions: D+P demonstrated a tolerable safety profile and response rate as expected for a 1L TNBC IO/taxane combination. D+T-DXd showed promising early safety and efficacy in 1L HER2-low–expressing TNBC; pt evaluation and enrollment for D+T-DXd are ongoing. D+T-DXd data will be updated and the impact of PD-L1 expression in both arms will be examined. Clinical trial information: NCT03742102 .

Subcutaneous trastuzumab with pertuzumab and docetaxel in HER2-positive metastatic breast cancer: Final analysis of MetaPHER, a phase IIIb single-arm safety study

Purpose

Intravenous trastuzumab, pertuzumab, and docetaxel are first-line standard of care for patients with HER2-positive metastatic breast cancer (mBC). MetaPHER is the first study assessing the safety and tolerability of subcutaneous trastuzumab plus intravenous pertuzumab and chemotherapy in a global patient population with HER2-positive mBC.

Methods

In this open-label, single-arm, multicenter, phase 3b study, eligible patients were ≥ 18 years old with histologically/cytologically confirmed previously untreated HER2-positive mBC. All received ≥ 1 subcutaneous trastuzumab 600 mg fixed dose plus intravenous pertuzumab (loading dose: 840 mg/kg; maintenance: 420 mg/kg) and docetaxel (≥ 6 cycles; initial dose 75 mg/m²) every 3 weeks. The primary objective was safety and tolerability; secondary objectives included efficacy.

Results

At clinical cutoff, 276 patients had completed the study; median duration of follow-up was 27 months. The most common any-grade adverse events were diarrhea, alopecia, and asthenia; the most common grade ≥ 3 events were neutropenia, febrile neutropenia, and hypertension. There were no cardiac deaths and mean left ventricular ejection fraction was stable over time. Median investigator-assessed progression-free survival was 18.7 months; objective response rate was 75.6%.

Conclusions

Safety and efficacy with subcutaneous trastuzumab plus intravenous pertuzumab and docetaxel in mBC are consistent with historical evidence of intravenous trastuzumab with this combination. Findings further support subcutaneous administration not affecting safety/efficacy profiles of trastuzumab in HER2-positive BC with increased flexibility in patient care. A fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection has recently been approved for the treatment of HER2-positive early/mBC, further addressing the increasing relevance of and need for patient-centric treatment strategies.

Trial registration

NCT02402712

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06145-3.

Abstract PD14-04: Contribution of tumor and immune cells to PD-L1 as a predictive biomarker in triple-negative breast cancer (TNBC): Analysis from KEYNOTE-119

Background: Pembrolizumab monotherapy did not significantly improve overall survival (OS) as second- or third-line treatment for metastatic TNBC vs chemotherapy in the randomized, open-label, phase 3 KEYNOTE-119 study (NCT02555657; N = 622). However, the benefit of pembrolizumab compared with chemotherapy appeared to be greater with increasing PD-L1 expression as quantified by combined positive score (CPS; defined as the number of PD-L1–staining cells [tumor cells, lymphocytes, macrophages] divided by the total number of viable tumor cells, multiplied by 100). In the current exploratory analysis, we aimed to determine whether expression of PD-L1 on tumor cells contributes to the value of PD-L1 as a predictive biomarker in metastatic TNBC.Methods: Patients with centrally confirmed TNBC and 1 or 2 prior systemic treatments for metastatic disease were enrolled in KEYNOTE-119. Patients were randomly assigned 1:1 to pembrolizumab 200 mg Q3W or investigator’s choice of single-agent chemotherapy (capecitabine, eribulin, gemcitabine, or vinorelbine). PD-L1 expression in tumor samples was assessed using PD-L1 IHC 22C3 pharmDx and quantified per tumor proportion score (TPS; defined as the percentage of PD-L1–expressing tumor cells [partial or complete membrane staining] relative to total number of tumor cells) and CPS. Quantitative immune cell density (QID) was defined as CPS minus TPS. QID isolates immune cells but may be truncated when TPS is high. The ability of each scoring method (TPS, CPS, and QID) to predict objective response rate (ORR) with pembrolizumab, including receiver operating characteristics (ROC) analysis, and OS hazard ratios (HRs; pembrolizumab vs chemotherapy) was evaluated.Results: Tumor samples were available for 601 patients (pembrolizumab, 309; chemotherapy, 292) in KEYNOTE-119. ORR was 9.7% (30/309) with pembrolizumab and 11.3% (33/292) with chemotherapy when PD-L1 expression status was not considered. In the pembrolizumab arm, the area under the ROC curve (AUROC; 95% CI) was 0.69 (0.58-0.80) for tumor samples scored for CPS, 0.66 (0.55-0.77) for QID, and 0.55 (0.46-0.64) for TPS. ROC analysis is shown in the Table. At each cutoff, QID had lower estimated sensitivity (ie, missed responders) and a lower Youden Index compared with CPS. The number of missed responders (of 30 total in the pembrolizumab arm) for QID relative to CPS were 2, 5, 5, 6, 2, and 2 at cutoffs of 1, 10, 20, 30, 40, and 50, respectively. Across all practical cutoffs, the OS HR tended to be slightly smaller for CPS than QID. At cutoffs corresponding to the upper percentiles of 10, 20, 40, and 60, OS HRs were 0.497, 0.658, 0.758, and 0.850, respectively, for CPS vs 0.572, 0.712, 0.814, and 0.863, respectively, for QID. QID appeared to be orthogonal to TPS (r = -0.03 for all 601 observations; r = -0.04 after eliminating 7 potentially truncated values).Conclusions: Trends estimated using KN119 suggest that tumor cell expression is an important component of PD-L1 as a predictive biomarker of pembrolizumab efficacy in metastatic TNBC. In this exploratory analysis, when immune cells alone were used to measure PD-L1 expression, a meaningful number of responders was missed and OS benefit trended toward higher HR estimates. Tumor and immune cell PD-L1 expression may represent distinct (presumably negative modulatory) mechanisms.

Table. ROC AnalysisCutoffCPS SensCPS SpecCPS YICPS PrevQID SensQID SpecQID YIQID PrevTPS SensTPS SpecTPS YITPS Prev010011001100110.8330.3660.1990.6540.7670.4160.1820.6020.3000.7890.0890.220100.5670.7170.2840.3110.4000.8140.2140.2070.2000.8920.0920.117200.5000.8490.3490.1840.3330.9250.2580.1000.1670.9320.0990.078300.3670.8920.2590.1330.1670.9570.1240.0550.1000.9430.0430.061400.2000.9350.1350.0780.1330.9860.1190.0260.0670.9530.0200.049500.2000.9570.1570.0580.1330.9930.1260.0190.0670.9680.0340.036

Citation Format: Eric P. Winer, Oleg Lipatov, Seock-Ah Im, Anthony Goncalves, Eva Muñoz-Couselo, Keun Seok Lee, Zbigniew Nowecki, Peter Schmid, Kenji Tamura, Laura Testa, Isabell Witzel, Shoichiro Ohtani, Stephanie Hund, Karina Kulangara, Vassiliki Karantza, Jaime A. Mejia, Junshui Ma, Petar Jelinic, Lingkang Huang, Kenneth Emancipator, Javier Cortes. Contribution of tumor and immune cells to PD-L1 as a predictive biomarker in triple-negative breast cancer (TNBC): Analysis from KEYNOTE-119 [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD14-04.

Abstract PS10-12: Integrated safety summary of single agent and combination margetuximab in phase 1, 2, and 3 studies of HER2-positive advanced cancers and metastatic breast cancer (MBC)

Background Margetuximab (M) is an investigational Fc-engineered anti-HER2 monoclonal antibody that targets the same epitope as trastuzumab (T). Compared with T, M has higher affinity for both the 158V (high-binding) and 158F (low-binding) allotypes of the activating Fc receptor CD16A. M enhances innate immunity more effectively than T in vitro, including CD16A-mediated antibody-dependent cellular cytotoxicity. Samples collected from patients (pts) before and after single-agent treatment also demonstrate that M induces HER2-specific adaptive immune responses, including both T- and B-cell responses. The SOPHIA trial (NCT02492711) in pts with pretreated HER2+ MBC showed that M+chemotherapy (chemo) improved progression-free survival vs T+chemo, with comparable safety. A pooled analysis of M safety across 3 clinical trials is presented. Methods Study 01 (NCT01148849), an ongoing Phase 1 dose-finding/safety study of M monotherapy, enrolled 66 pts with advanced HER2+ carcinomas, including 27 with MBC. Study 02 (NCT01828021), a completed Phase 2 study of M monotherapy in low-expressing HER2+ MBC, enrolled 25 pts. Study 04 (NCT02492711), an ongoing Phase 3 study in pts with pretreated HER2+ MBC to compare M + chemo vs T + chemo, randomized 536 pts, of whom 264 and 265 received M and T, respectively. The pooled safety population includes all pts who received any M in Study 01 (cutoff 01Oct2015), Study 02 (cutoff 02Aug2017), and Study 04 (cutoff 10OCT2018). Treatment-emergent adverse events (AEs), defined as AEs that began or worsened in severity on or after first dose of study drug through an End of Treatment Visit or 28 days after last study treatment, are reported. Results Of 355 pts that received at least 1 dose of M, 295 received 15 mg/kg Q3W, and 60 received other doses from 0.1 - 18 mg/kg. Median (mean, range) number of cycles for all dose levels was 5.0 (6.6, 1-43), higher on Study 04 (6.0) than Study 01 (1-3 across dose groups) or Study 02 (2.0). Most pts (347 [97.7%]) experienced at least 1 AE, and about half (173 [48.7%]) had at least 1 Grade &gt;/= 3 AE. Serious AE (SAE) incidence across studies was low (58 [16.3%]), and 21 pts (5.9%) discontinued M due to AEs. Most frequently reported AEs (&gt;/= 20%) were fatigue (124 [34.9]), nausea (103 [29.0%]), diarrhea (75 [21.1%]), and neutropenia (75 [21.1%]). Blood/lymphatic system disorders were the most frequent events by SOC, and largely restricted to Study 04. Increased neutropenia on M (26.1%), relative to T (20.4%), was observed in Study 04 yet both febrile neutropenia (M 3.0%, T 4.5%) and infections (M 36.4%, T 39.6%) were higher on T. By contrast, Study 01 and Study 02 revealed no tendency of M monotherapy to cause neutropenia. Overall, infusion related reactions (IRRs) were observed in 51 pts (14.4%), primarly at first infusion, including serious IRRs in 5 (1.4%). Also, 34 pts (9.6%) had &gt; 15% reduction in LVEF with a median time to &gt; 15% reduction of 49 days. In all pts with complete follow-up, these LVEF reductions were asymptomatic and reversible. No M-induced cardiac conduction abnormalities were noted. In Study 04, similar proportions in both groups experienced AEs (M 97.7%, T 96.2%), including Grade &gt;/= 3 AEs (M 52.3%, T 48.3%), SAEs (M 14.8%, T 17.4%), discontinuations due to AEs (M 3.0%, T 2.6%), and deaths due to AEs (M 0.8%, T 0.8%). As of the 23Feb2020 safety update, 2 pts remain on M in Study 01, after 116 and 109 cycles (6.7 and 6.3 years), respectively. In Study 04, 16 pts (6%) continued on M, and 7 (2.6%) remained on T. Discussion M has demonstrated an acceptable safety profile across Phase 1, 2, and 3 studies. It has been administered for over 6 years without long-term cumulative safety issues. Combined M plus chemotherapy Q3W demonstrated acceptable safety and tolerability, similar to that for T plus chemotherapy Q3W in Study 04.

Citation Format: Seock-Ah Im, Fatima Cardoso, Javier Cortes, Giuseppe Curigliano, Mark D. Pegram, Hope S. Rugo, Ursa Brown-Glaberman, Denise A. Yardley, Sung-Bae Kim, Maaike de Boer, Zbigniew Nowecki, Vesna Glavicic, Ido Wolf, Nele Claes, Joo Hyuk Sohn, Thomas Bachelot, Peter A. Kaufman, Jan Baughman, Shengyan Hong, Kenneth Jacobs, Edwin Rock, William J. Gradishar. Integrated safety summary of single agent and combination margetuximab in phase 1, 2, and 3 studies of HER2-positive advanced cancers and metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-12.

Abstract GS4-01: Results from CONTESSA: A phase 3 study of tesetaxel plus a reduced dose of capecitabine versus capecitabine alone in patients with HER2-, hormone receptor + (HR+) metastatic breast cancer (MBC) who have previously received a taxane

Objectives: The key objectives of CONTESSA are to evaluate the efficacy and safety of tesetaxel plus a reduced dose of capecitabine as an all-oral regimen versus capecitabine alone in patients with HER2-, HR+ MBC previously treated with a taxane.

Rationale: Tesetaxel is a novel, oral taxane with several properties that make it unique, including: oral administration with a low pill burden; a long (8-day) terminal plasma half-life in humans, enabling infrequent, once-every-3 weeks (Q3W) dosing; no observed hypersensitivity reactions; and significant activity against chemotherapy-resistant breast cancer cell lines. More than 1,000 patients have been treated with tesetaxel in clinical studies. Tesetaxel had encouraging monotherapy activity in a Phase 2 study in 38 patients with HER2-, HR+ MBC, with a confirmed objective response rate (ORR) per RECIST 1.1 of 45% and median progression-free survival (PFS) of 5.4 months (Seidman et al, 2018 ASCO Annual Meeting).

Methodology: CONTESSA is a multinational, multicenter, randomized (1:1), Phase 3 registration study comparing tesetaxel (27 mg/m2 on Day 1 of a 21-day cycle) plus a reduced dose of capecitabine (1,650 mg/m2/day on Days 1-14 of a 21-day cycle) to the approved dose of capecitabine alone (2,500 mg/m2/day on Days 1-14 of a 21-day cycle) in patients with HER2-, HR+ MBC who have received no more than one chemotherapy regimen for advanced disease and have received a taxane in the (neo)adjuvant setting. There was no restriction on the disease-free interval following taxane therapy. The primary endpoint is PFS assessed by an Independent Radiologic Review Committee (IRC). CONTESSA was designed with 90% power to detect a 2.5-month improvement in median PFS (HR=0.71). Secondary endpoints are overall survival (OS), ORR and disease control rate.

Results: CONTESSA, which enrolled 685 patients, met the primary endpoint of improved PFS as assessed by the IRC. Median PFS was 9.8 months for tesetaxel plus a reduced dose of capecitabine versus 6.9 months for capecitabine alone, an improvement of 2.9 months [HR=0.716 (95% CI: 0.573-0.895); p=0.003]. ORR was 57% for tesetaxel plus a reduced dose of capecitabine versus 41% for capecitabine alone (p=0.0002). OS data are immature. Tesetaxel plus capecitabine was associated with a manageable side effect profile consistent with previous clinical studies. Grade ≥3 treatment-emergent adverse events (TEAEs) that occurred in ≥5% of patients (tesetaxel plus capecitabine vs. capecitabine alone) were: neutropenia (71.2% vs. 8.3%); diarrhea (13.4% vs. 8.9%); hand-foot syndrome (6.8% vs. 12.2%); febrile neutropenia (12.8% vs. 1.2%); fatigue (8.6% vs. 4.5%); hypokalemia (8.6% vs. 2.7%); leukopenia (10.1% vs. 0.9%); and anemia (8.0% vs. 2.1%). TEAEs resulting in treatment discontinuation in ≥1% of patients (tesetaxel plus capecitabine vs. capecitabine alone) were: neutropenia or febrile neutropenia (4.2% vs. 1.5%); neuropathy (3.6% vs. 0.3%); diarrhea (0.9% vs. 1.5%); and hand-foot syndrome (0.6% vs. 2.1%). Treatment discontinuation due to any adverse event occurred in 23.1% of patients treated with tesetaxel plus capecitabine versus 11.9% of patients treated with capecitabine alone. Grade 2 alopecia occurred in 8.0% of patients treated with tesetaxel plus capecitabine versus 0.3% of patients treated with capecitabine alone. Grade ≥3 neuropathy occurred in 5.9% of patients treated with tesetaxel plus capecitabine versus 0.9% of patients treated with capecitabine alone.

Conclusion: An all-oral regimen of tesetaxel plus a reduced dose of capecitabine significantly improved PFS versus capecitabine alone. Neutropenia was the most frequent Grade ≥3 TEAE. Rates of clinically significant alopecia and neuropathy were low.

Citation Format: Joyce O'Shaughnessy, Lee Schwartzberg, Martine Piccart, Hope S. Rugo, Denise A Yardley, Javier Cortes, Michael Untch, Nadia Harbeck, Gail S. Wright, Igor Bondarenko, John Glaspy, Zbigniew Nowecki, Fadi Kayali, Arlene Chan, Christelle Levy, Mei-Ching Liu, Sung-Bae Kim, Julie Lemieux, Alexey Manikhas, Sara Tolaney, Elaine Lim, Andrea Gombos, Agostina Stradella, Mark Pegram, Peter Fasching, Laszlo Mangel, Vladimir Semiglazov, Veronique Dieras, Luca Gianni, Michael A Danso, Jeff Vacirca, Stew Kroll, Joseph O'Connell, Kevin Tang, Thomas Wei, Andrew Seidman. Results from CONTESSA: A phase 3 study of tesetaxel plus a reduced dose of capecitabine versus capecitabine alone in patients with HER2-, hormone receptor + (HR+) metastatic breast cancer (MBC) who have previously received a taxane [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS4-01.

Abstract GS3-01: Additional efficacy endpoints from the phase 3 KEYNOTE-355 study of pembrolizumab plus chemotherapy vs placebo plus chemotherapy as first-line therapy for locally recurrent inoperable or metastatic triple-negative breast cancer

Background: Pembrolizumab (pembro) monotherapy showed durable antitumor activity and manageable safety in patients (pts) with metastatic triple-negative breast cancer (TNBC) in the KEYNOTE-012, -086, and -119 studies. In a prespecified interim analysis of KEYNOTE-355 (NCT02819518), pembro combined with chemotherapy (chemo) showed a statistically significant improvement in PFS versus chemo alone in pts with previously untreated locally recurrent inoperable or metastatic TNBC whose tumors expressed PD-L1 CPS ≥10 (HR for progression or death, 0.65, 95% CI, 0.49-0.86; one-sided P=0.0012 [prespecified statistical criterion was alpha=0.00411 at this interim analysis]). Additionally, pembro + chemo was generally well tolerated, with no new safety signals. Here, we examine PFS outcomes for each chemo partner and present key secondary endpoints from KEYNOTE-355.

Methods: 847 pts with measurable disease per RECIST v1.1, ECOG PS 0-1, and ≥6 mo DFI were randomized 2:1 to pembro + chemo (nab-paclitaxel 100 mg/m2 days 1, 8, and 15 every 28 days; paclitaxel 90 mg/m2 days 1, 8, and 15 every 28 days; or gemcitabine 1000 mg/m2 + carboplatin AUC 2 days 1 and 8 every 21 days) or pbo + chemo for up to 35 administrations of pembro/pbo or until progression/intolerable toxicity. Steroid premedication for paclitaxel was given according to local guidelines and practices, and was not restricted by the protocol. Crossover between arms was not allowed. Pts were stratified by chemo type (taxane vs gemcitabine/carboplatin), PD-L1 status (CPS ≥1 vs &lt;1), and prior (neo)adjuvant treatment with same-class chemo (yes vs no). Dual primary endpoints are PFS (RECIST v1.1, blinded independent central review) and OS in pts with PD-L1 positive tumors (CPS ≥10 and ≥1) and in all pts. Secondary endpoints include ORR, DCR (CR + PR + SD ≥24 weeks), and DOR. The PFS treatment effect was assessed in subgroups descriptively using HRs and 95% CIs; although subgroup analysis by on-study chemo were pre-specified, the trial was not powered to compare efficacy among treatment groups by different chemo regimens.

Results: As of Dec 11 2019, median follow-up was 25.9 mo for pembro + chemo (n=566) and 26.3 mo for pbo + chemo (n=281). The HR for PFS favored pembro regardless of choice of chemo or CPS population (Table). Results for the key secondary endpoints of ORR, DCR, and DOR favored pembro + chemo, with the treatment effect increasing as CPS increased (Table).

Conclusion: In subgroup analysis, PFS with pembro + chemo compared to pbo + chemo in pts with metastatic TNBC was improved regardless of chemo partner. A trend toward improved efficacy with PD-L1 enrichment with pembro + chemo was observed for ORR, DCR and DOR endpoints. These data further support the potential of pembro + chemo as a first-line treatment option for metastatic TNBC.

CPS ≥ 10CPS ≥ 1All ptsPembro + ChemoPbo + ChemoPembro + ChemoPbo + ChemoPembro + Chemo|Pbo + ChemoN = 220N = 103N = 425N = 211N = 566N = 281PFS, mo median (95% CI)9.7 (7.6 - 11.3)5.6 (5.3 - 7.5)7.6 (6.6 - 8.0)5.6 (5.4 - 7.4)7.5 (6.3 - 7.7)5.6 (5.4 - 7.3)HR (95% CI)0.65 (0.49 - 0.86)0.74 (0.61 - 0.90)0.82 (0.69 - 0.97)PFS by on-study chemo, (n [%)) mo median(95% CI)Nab-Paclitaxel(63 [28.6%]) 9.9(36 [35.0%]) 5.5(130 [30.6%]) 6.3(74 [35.1%)) 5.3(173 [30.6%]) 7.5(95 [33.8%]) 5.4HR (95% CI)0.57 (0.34 - 0.95)0.66 (0.26 - 0.82)0.69 (0.51 - 0.93)Paclitaxel(33 [15.0%]) 9.6(11 [10.7%]) 3.6(62 [14.6%]) 9.4(22 [10.4%]) 3.8(82 [14.5%]) 8.0(32 [11.4%]) 3.8HR (95% CI)0.33 (0.14 - 0.76)0.46 (0.26 - 0.82)0.57 (0.35 - 0.93)Gemcitabine-Carboplatin(124 [56.4%]) 8.0(56 [54.4%]) 7.2(233 [54.8%]) 7.5(115 [54.5%]) 7.5(311 [54.9%]) 7.4(154 [54.8%]) 7.4HR (95% CI)0.77 (0.53 - 1.11)0.86 (0.66 - 1.11)0.93 (0.74 - 1.16)ORR, % (95% CI)53.2 (46.4 - 59.9)39.8 (30.3 - 49.9)45.2 (40.4 - 50.0)37.9 (31.3 - 44.8)41.0 (36.9 - 45.2)35.9 (30.3 - 41.9)DCR, % (95% CI)65.0 (58.3 - 71.3)54.4 (44.3 - 64.2)58.6 (53.7 - 63.3)53.6 (46.6 - 60.4)56.0 (51.8 - 60.1)51.6 (45.6 - 57.6)DOR, mo, median (range)19.3 (1.6+ - 29.8)7.3 (1.5 - 32.5+)10.1 (1.0+ - 29.8)6.5 (1.5 - 32.5+)10.1 (1.0+ - 29.8)6.4 ( 1.5 - 32.5+)"+" indicates there is no progressive disease by the time of last disease assessment.

Citation Format: Hope S. Rugo, Peter Schmid, David W. Cescon, Zbigniew Nowecki, Seock-Ah Im, Mastura Md Yusof, Carlos Gallardo, Oleg Lipatov, Carlos Henrique Barrios, Jose Perez-Garcia, Hiroji Iwata, Norikazu Masuda, Marco Torregroza Otero, Erhan Gokmen, Sherene Loi, Zifang Guo, Jing Zhao, Vassiliki Karantza, Gursel Aktan, Javier Cortes. Additional efficacy endpoints from the phase 3 KEYNOTE-355 study of pembrolizumab plus chemotherapy vs placebo plus chemotherapy as first-line therapy for locally recurrent inoperable or metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS3-01.

Fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection plus chemotherapy in HER2-positive early breast cancer (FeDeriCa): a randomised, open-label, multicentre, non-inferiority, phase 3 study

BACKGROUND

A subcutaneous formulation of pertuzumab and trastuzumab with recombinant human hyaluronidase in one ready-to-use, fixed-dose combination vial (pertuzumab, trastuzumab, and hyaluronidase-zzxf) was approved by the US Food and Drug Administration (FDA) on June 29, 2020. We report the primary analysis of the FeDeriCa study, which was designed to assess the pharmacokinetics, efficacy, and safety of the fixed-dose subcutaneous formulation compared to intravenous pertuzumab plus trastuzumab in patients with HER2-positive early breast cancer in the neoadjuvant-adjuvant setting.

METHODS

FeDeriCa, a randomised, open-label, international, multicentre, non-inferiority, phase 3 study, was done across 106 sites in 19 countries. Patients aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0 or 1, HER2-positive, operable, locally advanced, or inflammatory stage II-IIIC breast cancer, and a left ventricular ejection fraction of 55% or more were randomly assigned (1:1), using a voice-based or web-based response system, to receive intravenous pertuzumab (840 mg loading dose, followed by 420 mg maintenance doses) plus intravenous trastuzumab (8 mg/kg loading dose, followed by 6 mg/kg maintenance doses) or the fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection (1200 mg pertuzumab plus 600 mg trastuzumab loading dose in 15 mL, followed by 600 mg pertuzumab plus 600 mg trastuzumab maintenance doses in 10 mL), both administered every 3 weeks with neoadjuvant chemotherapy. Patients were stratified by hormone receptor status, clinical stage, and chemotherapy regimen. The investigator selected one of the two protocol-approved standard chemotherapy regimens before randomisation. Four cycles of HER2-targeted therapy were administered concurrently with the taxane. After surgery, patients continued the HER2-targeted therapy to receive an additional 14 cycles (total of 18). The primary endpoint was non-inferiority of the cycle 7 pertuzumab serum trough concentration (C_trough; ie, cycle 8 predose pertuzumab concentration) within the fixed-dose combination for subcutaneous injection versus intravenous pertuzumab plus trastuzumab in the per-protocol pharmacokinetic population (all enrolled patients who adhered to prespecified criteria for pharmacokinetic assessment). Non-inferiority was concluded if the lower bound of the 90% CI of the geometric mean ratio was 0·8 or higher. The safety population included all patients who received at least one dose of study medication, including chemotherapy or HER2-targeted therapy. Enrolment, neoadjuvant therapy, and surgery have been completed; adjuvant treatment and follow-up are ongoing. The trial is registered with ClinicalTrials.gov, NCT03493854.

FINDINGS

Between June 14, 2018, and Dec 24, 2018, 252 patients were randomly assigned to the intravenous infusion group and 248 to the fixed-dose combination group. The geometric mean ratio of pertuzumab serum C_trough subcutaneous to serum C_trough intravenous was 1·22 (90% CI 1·14-1·31). The most common grade 3-4 adverse events occurring during neoadjuvant treatment with HER2-targeted therapy plus chemotherapy in 5% or more of patients were neutropenia (34 [13%] of 252 patients in the intravenous infusion group vs 35 [14%] of 248 patients in the fixed-dose combination group), decreased neutrophil count (31 [12%] vs 27 [11%]), febrile neutropenia (14 [6%] vs 16 [6%]), diarrhoea (12 [5%] vs 17 [7%]), and decreased white blood cell count (18 [7%] vs nine [4%]). At least one treatment-related serious adverse event was reported in 25 (10%) patients in the intravenous infusion group and 26 (10%) patients in the fixed-dose combination group. One patient in each treatment group had an adverse event that led to death (urosepsis in the intravenous infusion group and acute myocardial infarction in the fixed-dose combination group); neither death was related to HER2-targeted therapy.

INTERPRETATION

The study met its primary endpoint: the fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection provides non-inferior cycle 7 pertuzumab serum C_trough concentrations to intravenous pertuzumab plus trastuzumab in the neoadjuvant setting with comparable total pathological complete response rates, supporting the FDA approval. Safety was similar between treatment groups, and in line with other pertuzumab, trastuzumab, and chemotherapy trials. Follow-up is ongoing for long-term outcomes, including efficacy and long-term safety.

FUNDING

F Hoffmann-La Roche and Genentech.

Pembrolizumab plus chemotherapy versus placebo plus chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer (KEYNOTE-355): a randomised, placebo-controlled, double-blind, phase 3 clinical trial

BACKGROUND

Pembrolizumab monotherapy showed durable antitumour activity and manageable safety in patients with metastatic triple-negative breast cancer. We aimed to examine whether the addition of pembrolizumab would enhance the antitumour activity of chemotherapy in patients with metastatic triple-negative breast cancer.

METHODS

In this randomised, placebo-controlled, double-blind, phase 3 trial, done in 209 sites in 29 countries, we randomly assigned patients 2:1 with untreated locally recurrent inoperable or metastatic triple-negative breast cancer using a block method (block size of six) and an interactive voice-response system with integrated web-response to pembrolizumab (200 mg) every 3 weeks plus chemotherapy (nab-paclitaxel; paclitaxel; or gemcitabine plus carboplatin) or placebo plus chemotherapy. Randomisation was stratified by type of on-study chemotherapy (taxane or gemcitabine-carboplatin), PD-L1 expression at baseline (combined positive score [CPS] ≥1 or <1), and previous treatment with the same class of chemotherapy in the neoadjuvant or adjuvant setting (yes or no). Eligibility criteria included age at least 18 years, centrally confirmed triple-negative breast cancer; at least one measurable lesion; provision of a newly obtained tumour sample for determination of triple-negative breast cancer status and PD-L1 status by immunohistochemistry at a central laboratory; an Eastern Cooperative Oncology Group performance status score 0 or 1; and adequate organ function. The sponsor, investigators, other study site staff (except for the unmasked pharmacist), and patients were masked to pembrolizumab versus saline placebo administration. In addition, the sponsor, the investigators, other study site staff, and patients were masked to patient-level tumour PD-L1 biomarker results. Dual primary efficacy endpoints were progression-free survival and overall survival assessed in the PD-L1 CPS of 10 or more, CPS of 1 or more, and intention-to-treat populations. The definitive assessment of progression-free survival was done at this interim analysis; follow-up to assess overall survival is continuing. For progression-free survival, a hierarchical testing strategy was used, such that testing was done first in patients with CPS of 10 or more (prespecified statistical criterion was α=0·00411 at this interim analysis), then in patients with CPS of 1 or more (α=0·00111 at this interim analysis, with partial alpha from progression-free survival in patients with CPS of 10 or more passed over), and finally in the intention-to-treat population (α=0·00111 at this interim analysis). This study is registered with ClinicalTrials.gov, NCT02819518, and is ongoing.

FINDINGS

Between Jan 9, 2017, and June 12, 2018, of 1372 patients screened, 847 were randomly assigned to treatment, with 566 patients in the pembrolizumab-chemotherapy group and 281 patients in the placebo-chemotherapy group. At the second interim analysis (data cutoff, Dec 11, 2019), median follow-up was 25·9 months (IQR 22·8-29·9) in the pembrolizumab-chemotherapy group and 26·3 months (22·7-29·7) in the placebo-chemotherapy group. Among patients with CPS of 10 or more, median progression-free survival was 9·7 months with pembrolizumab-chemotherapy and 5·6 months with placebo-chemotherapy (hazard ratio [HR] for progression or death, 0·65, 95% CI 0·49-0·86; one-sided p=0·0012 [primary objective met]). Median progression-free survival was 7·6 and 5·6 months (HR, 0·74, 0·61-0·90; one-sided p=0·0014 [not significant]) among patients with CPS of 1 or more and 7·5 and 5·6 months (HR, 0·82, 0·69-0·97 [not tested]) among the intention-to-treat population. The pembrolizumab treatment effect increased with PD-L1 enrichment. Grade 3-5 treatment-related adverse event rates were 68% in the pembrolizumab-chemotherapy group and 67% in the placebo-chemotherapy group, including death in <1% in the pembrolizumab-chemotherapy group and 0% in the placebo-chemotherapy group.

INTERPRETATION

Pembrolizumab-chemotherapy showed a significant and clinically meaningful improvement in progression-free survival versus placebo-chemotherapy among patients with metastatic triple-negative breast cancer with CPS of 10 or more. These findings suggest a role for the addition of pembrolizumab to standard chemotherapy for the first-line treatment of metastatic triple-negative breast cancer.

FUNDING

Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc.

Clinical value of kinase Aurora-A serum level determination in patients with breast cancer qualified for neoadjuvant chemotherapy: Pilot study

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Background: Aurora A (AURKA) is serine/threonine kinase that plays a regulatory role in mitosis and multiple signaling pathways. Overexpression of AURKA has been found in many solid tumors including breast cancer. It also has been found to be a prognostic marker indicating resistance to taxane treatment and poor prognosis in ER positive breast cancer. The aim of this study is to assess clinical value of Aurora-A serum level determination in patients with breast cancer qualified for neoadjuvant chemotherapy. Methods: 60 patients with confirmed breast cancer before treatment were qualified for the study, aged 31-77 (median 52 years), including 30 premnopausal and 30 pomenopausal. The control group consisted of 30 healthy women aged 20-80 (median 53 years). Clinical and pathological features were determined in a selected group of patients with breast cancer who subsequently underwent preoperative chemotherapy, i.e. tumor size (T), lymph node status (N), presence of distant metastases (M), estrogen receptor status (ER) and progesterone (PgR), HER2 receptors and Ki 67 proliferative index. The blood serum of the examined patients and healthy women was determined by the enzyme-linked ELISA method in doublets of the AURKA biomarker concentration. Mann-Whitney test and ROC curve analysis were used for statistical calculations. Results: No significant differences were found between the concentrations of AURKA in breast cancer patients and in the control group. In both analyzed groups there were no significant differences in biomarker levels depending on the menopausal status. When assessing the relationship between AURKA concentrations and clinical-pathological features, significant differences were found depending on the state of the lymph nodes (N0 vs N1 + N2) (p = 0.006). There was no correlation between the concentrations of the tested biomarker and the tumor size (T), the state of receptors and the Ki67 index. In patients with a lack of receptors (triple negative vs others), higher levels of Aurora A (p = 0.06) in the blood serum were observed at the level of the statistical trend. Conclusions: The preliminary results obtained indicate the potential usefulness of determining the concentration of the new biomarker Aurora A in the blood serum of patients with breast cancer. The research is continuing.

Prognostic and predictive value of neutrophil/lymphocyte ratio in patients with triple-negative and HER2-positive breast cancer undergoing neoadjuvant systemic therapy

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Background: Preoperative neutrophil-lymphocyte ratio (NLR) have been suggested to be correlated with the prognosis of patients with breast cancer (BC). However, the results still remain controversial. The goal of our study was to evaluate the predictive and prognostic value of NLR in early stage triple negative and HER2-pos breast cancer patients undergoing NAC. Methods: 96 female patients (pts) with histologically proven breast cancer (51 TNBC, and 45 HER2 pos) were analysed in this retrospective analysis. The NLR before the initiation of NAC was documented. Histopathological response in surgically removed specimens was evaluated using the Residual Cancer Burden (RCB) Calculator (by MD Anderson Cancer Center). The pCR was defined as no invasive tumor in primary tumor bed and lymph nodes. The NLR variable was analyzed as both continuous and categorical. The impact on pCR and RCB was tested using Mann-Whitney, Kruskal-Willis or the Chi-2 test, respectively. Results: Only 4 categories of NAC were used: in TNBC 4 x ACdd followed by 12 x PCL (38 pts) or 4 x ACdd followed by 12 x PCL+ carboplatin AUC 1.0-2 (13 pts), in HER2-pos 39 pts received 6 x TCH (docetaxel + tratuzumab + carboplatin AUC 6) and 6 pts 4 x ACdd followed by 12 x PCL iv + 4 x trastuzumab. In 27 pts (53%) with TNBC and 24 pts (53%) with HER2-pos breast cancer pCR was obtained after NAC. RCB distribution was: 0-53.1%, 1-22%, 2-17.6%, 3-7.3%. No association with NLR and pCR could be observed (p > 0.26). No association with NLR and RCB could be observed (p > 0.18). Conclusions: In our retrospective analysis we could not demonstrate predictive or prognostic value of NLR in the cohort of early stage triple negative and HER2-positive breast cancer patients treated with NAC. Further studies are planned in a group of patients with Luminal B, HER2 – negative breast cancer, who received NAC.

Primary analysis of KAITLIN: A phase III study of trastuzumab emtansine (T-DM1) + pertuzumab versus trastuzumab + pertuzumab + taxane, after anthracyclines as adjuvant therapy for high-risk HER2-positive early breast cancer (EBC)

500

Background: The standard of care for HER2-positive EBC is chemotherapy plus one year of HER2-directed therapy. However, recurrence—particularly in high-risk populations—remains a problem, as does systemic chemotherapy-associated toxicity. In KAITLIN, we aimed to improve efficacy and reduce toxicity by replacing taxanes and trastuzumab with T-DM1. Methods: KAITLIN (NCT01966471) is a phase 3, randomized, open-label study that enrolled 1846 patients with adequately excised, centrally confirmed HER2-positive EBC either node-positive (LN+); or node-negative, HR-negative, and tumor size > 2.0 cm. Within 9 weeks of surgery, patients were randomized 1:1 to 3-4 cycles of anthracycline-based chemotherapy followed by 18 cycles of T-DM1 3.6 mg/kg + pertuzumab 420 mg q3w (loading dose [LD] 840 mg) (AC-KP) or taxane (3-4 cycles) + concurrent trastuzumab 6 mg/kg (LD 8 mg/kg) + pertuzumab 420 mg q3w (LD 840 mg) (AC-THP). Patients were stratified by world region, nodal status, HR status, and anthracycline type. Adjuvant radiotherapy and/or endocrine therapy was administered after 4 cycles of HER2-targeted therapy when indicated. The co-primary endpoints were invasive disease-free survival (IDFS) in the LN+ and in the ITT populations applying a hierarchical testing procedure. Secondary endpoints included overall survival (OS), patient-reported outcomes (PROs), and safety. Results: KAITLIN did not meet its co-primary endpoints. In LN+ patients (n = 1658), there was no significant difference between arms in IDFS event risk (stratified hazard ratio = 0.97; 95%CI 0.71–1.32). Three-year IDFS was 94.1% with AC-THP and 92.7% with AC-KP. Results were similar in the ITT population (stratified hazard ratio = 0.98; 95%CI 0.72–1.32; 3-year IDFS: 94.2% vs 93.1%). OS data are immature with an event rate of ~4%–5% in each arm. During the study overall, there was a similar incidence of grade ≥3 AEs (55.4% vs 51.8%) and SAEs (23.3% vs 21.4%) with AC-THP and AC-KP, respectively. More patients receiving AC-KP than AC-THP discontinued T-DM1 or trastuzumab, respectively, because of AEs (26.8% vs 4.0%). PRO data will be presented. Conclusions: Replacing adjuvant taxane and trastuzumab with T-DM1 did not result in significantly improved efficacy or overall safety. Nonetheless, in this high-risk population, a favorable IDFS outcome was achieved in both study arms. HP + chemotherapy remains the standard of care for patients with high-risk HER2-positive EBC. Clinical trial information: NCT01966471 .

Pathological outcomes of HER2-positive early breast cancer patients treated with neoadjuvant trastuzumab or dual anti-HER2 therapy and carboplatin with docetaxel: A Maria Sklodowska-Curie National Research Institute of Oncology experience

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Background: Pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) for breast cancer predicts the risk of recurrence and increasingly may indicate the need for additional therapy postoperatively. Methods: A retrospective analysis was performed in two cohorts of patients (pts) treated with docetaxel, trastuzumab and carboplatin (TCH) or with docetaxel, carboplatin and dual blockade (TCH-P) in the neoadjuvant setting in patients with early breast cancer (tumor size < 50 mm and > 10 mm and cN0 or cN1) in our Clinic, and who had definitive surgery was conducted. Demographic data, size, grade, tumor type, receptor status prior to neoadjuvant treatment, pathological complete response (pCR) rates, and adverse effects were analyzed. The pCR was defined as ypT0 ypN0. Results: Patient in cohort A (n = 58) received TCH x 6 cycles and in cohort B (n = 25) TCH-P x 6 cycles. Median age was 51 (range 23 to 76 years) in cohort A and 46 (range: 30-68) in cohort B. In cohort A 37 (64%) of pts was HR-positive, in cohort B only 9 (36%) pts . The most common adverse events in both groups were neutropenia, diarrhea, chemotherapy induced polyneuropathy and febrile neutropenia. There are no significant differences in the frequency of adverse events in two cohorts. There was no symptomatic heart failure, but 6 pts (10%) in cohort A and 5 pts (16%) in cohort B had > 10% asymptomatic decrease in LVEF. All patients were evaluable for pCR. Higher rates of pCR were achieved in the HER2pos/HRneg pts: 66% (n = 14) in cohort A, and 87% (n = 14) in cohort B. In group HER2pos/HRpos pts, the pCR rate was 48% (n = 18) vs 55% (n = 5) respectively. Conclusions: In HER2positive early breast cancer, a dual blockade (trastuzumab and pertuzumab) together with carboplatin and docetaxel neoadjuvant chemotherapy achieved higher rates of pCR ( 76%) compared with pts treated with trastuzumab, carboplatin and docetaxel (56%). However, a much higher percentage of pCR was observed in the group of patients with non-luminal cancers, who received a double blockade (87% vs 66%).

KEYNOTE-355: Randomized, double-blind, phase III study of pembrolizumab + chemotherapy versus placebo + chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer

1000

Background: Pembrolizumab (pembro) monotherapy showed promising antitumor activity and manageable safety in patients (pts) with metastatic TNBC in KEYNOTE-012, -086 and -119. KEYNOTE-355 (ClinicalTrials.gov, NCT02819518) compared pembro + chemotherapy (chemo) vs placebo (pbo) + chemo for previously untreated locally recurrent inoperable or metastatic TNBC. Methods: Pts with ≥6 mo DFI were randomized 2:1 to pembro + chemo (nab-paclitaxel; paclitaxel; or gemcitabine/carboplatin) or pbo + chemo for up to 35 administrations of pembro/pbo or until progression/intolerable toxicity. Pts were stratified by chemo type (taxane vs gemcitabine/carboplatin), PD-L1 status (CPS ≥1 vs <1), and prior (neo)adjuvant treatment with same-class chemo (yes vs no). Dual primary endpoints are PFS (RECIST v1.1, blinded independent central review) and OS by tumor PD-L1 expression (CPS ≥10 and ≥1) and in all pts. PFS was estimated using the Kaplan-Meier method. Stratified log-rank tests were used to assess treatment group differences. HR and 95% CIs were based on a stratified Cox regression model. AEs were monitored throughout the study and graded per NCI CTCAE v4.0. Results: As of Dec 11 2019, median follow-up was 17.5 mo for pembro + chemo (n=566) and 15.5 mo for chemo (n=281). Pembro + chemo significantly improved PFS vs chemo alone in pts with CPS ≥10 tumors (Table), meeting one of the protocol-defined primary objectives. Although the boundary for a statistically significant benefit of pembro + chemo in pts with CPS ≥1 tumors was not met and formal testing in ITT was not performed, the pembro treatment effect increased with PD-L1 enrichment (Table). OS follow-up is ongoing. Grade 3-5 treatment-related AE rates were 68.1% with pembro + chemo (2 deaths) vs 66.9% with chemo (0 deaths); rates of grade 3-4 immune-mediated AEs and infusion reactions were 5.5% vs 0%. Clinical trial information: NCT02819518 . Conclusion: Pembro combined with several chemo partners showed a statistically significant and clinically meaningful improvement in PFS vs chemo alone in pts with previously untreated locally recurrent inoperable or metastatic TNBC whose tumors expressed PD-L1 (CPS ≥10). Pembro + chemo was generally well tolerated, with no new safety concerns. [Table: see text]

Abstract PD4-07: Subcutaneous administration of the fixed-dose combination of trastuzumab and pertuzumab in combination with chemotherapy in HER2-positive early breast cancer: Primary analysis of the phase III, multicenter, randomized, open-label, two-arm FeDeriCa study

Background: Intravenous pertuzumab (P IV) + trastuzumab (H IV) + chemotherapy (CT) improves outcomes in patients (pts) with HER2-positive breast cancer, compared with H + CT.A new subcutaneous (SC) formulation, for the first time combining two monoclonal antibodies, P + H, with recombinant human hyaluronidase in one vial, was developed. This ready-to-use fixed-dose combination (PH FDC) is administered subcutaneously into the thigh over 5-8 minutes. The dose of H SC was confirmed in the phase III HannaH trial (NCT00950300) and the dose of P SC was established in a phase Ib study (NCT02738970). We report the first results from FeDeriCa (NCT03493854), which was designed to assess the pharmacokinetics, efficacy, and safety of this novel SC PH FDC compared with H IV + P IV in pts with HER2-positive early breast cancer in the neoadjuvant-adjuvant setting.

Methods: Pts with centrally confirmed HER2-positive invasive breast cancer (tumor &gt;2 cm, or node-positive disease; Stage II-IIIC) were randomized 1:1 to receive 8 cycles of CT in the neoadjuvant setting with H IV (loading dose 8 mg/kg, maintenance 6 mg/kg) + P IV (loading dose 840 mg, maintenance 420 mg) (Arm A) or CT per Arm A + PH FDC (loading dose 1200 mg P SC/600 mg H SC, maintenance 600 mg each; Arm B) administered q3w during cycles 5-8. CT was investigator’s choice of either 4 cycles of dose-dense doxorubicin + cyclophosphamide q2w → 4 cycles of weekly paclitaxel (total: 12 weeks), or 4 cycles of doxorubicin + cyclophosphamide q3w → 4 cycles of docetaxel q3w. Post-surgery, pts continued anti-HER2 treatment per randomization to complete 18 cycles. The primary objective was noninferiority (NI) of the pre-dose cycle 8 P serum trough concentration (Ctrough) within the PH FDC versus P IV (NI margin for the lower bound of the 90% confidence interval [CI] of the geometric mean ratio [GMR]: ≥0.8). Key secondary objectives were NI of pre-dose cycle 8 H Ctrough within the PH FDC versus H IV, total pathologic complete response in the breast and axilla (ypT0/is, ypN0; tpCR), and safety (primary cardiac events were defined as heart failure [New York Heart Association III + IV] with significant left ventricular ejection fraction [LVEF] decline; cardiac death. Secondary cardiac events were defined as LVEF decline ≥10% from baseline to below 50% and confirmed LVEF decline).

Results: Five-hundred pts were randomized (252 to Arm A, 248 to Arm B - ITT and safety populations) from 06/14/18-12/24/18 at 122 sites. At clinical cutoff (07/04/19), 242 pts (96.0%) in Arm A and 234 (94.4%) in Arm B completed the neoadjuvant treatment phase. Baseline pt demographics and disease characteristics were well balanced between arms.The study met its primary endpoint: P GMR was 1.22 (90% CI 1.14-1.31) with the lower limit of the 90% CI being above the prespecified NI margin of 0.8. H GMR was 1.33 (90% CI 1.24-1.43), meeting the NI criteria. tpCR rates were comparable between arms (59.5%; 95% CI 53.2-65.6 in Arm A and 59.7%; 95% CI 53.3-65.8 in Arm B) and were similar to other P + H + CT trials. Overall safety, including cardiac safety, was comparable between arms (Table). Safety was as expected for P + H + CT trials.

Conclusions: SC PH FDC demonstrated noninferior pre-dose cycle 8 P + H Ctrough to that of P IV + H IV, with comparable efficacy and safety. PH FDC offers a faster and simpler method of P + H administration for HER2-positive breast cancer.

Pts, %Arm A n = 252Arm B n = 248Any AE in &gt;50% of pts99.6100Alopecia70.277.0Nausea60.358.9Diarrhea55.258.5Grade ≥352.848.8Serious17.916.1CardiacPrimary00.8Secondary3.61.6Asymptomatic LVEF decline needing treatment/discontinuation4.02.0Death0.4*0.4** Unrelated to HER2 treatment

Citation Format: Antoinette R Tan, Seock-Ah Im, Andre Mattar, Ramon Colomer, Daniil Stroyakovskii, Zbigniew Nowecki, Michelino De Laurentiis, Jean-Yves Pierga, Kyung Hae Jung, Christian Schem, Sarah Heeson, Mahesh Shivhare, Whitney P. Kirschbrown, Eleonora Restuccia, Tanja Badovinac Crnjevic, Christian Jackisch. Subcutaneous administration of the fixed-dose combination of trastuzumab and pertuzumab in combination with chemotherapy in HER2-positive early breast cancer: Primary analysis of the phase III, multicenter, randomized, open-label, two-arm FeDeriCa study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD4-07.

Abstract P1-18-05: Subcutaneous trastuzumab and hyaluronidase-oysk with intravenous pertuzumab and docetaxel in HER2-positive advanced breast cancer: Final analysis of the phase IIIb, multicenter, open-label, single-arm MetaPHER study

Background Previous trials showed that fixed-dose subcutaneous trastuzumab and hyaluronidase-oysk (Herceptin Hylecta™; H SC) was non-inferior to weight-based intravenous trastuzumab (Herceptin®; H IV) in terms of pathologic complete response and serum trough concentration in HER2-positive early breast cancer (BC), with a comparable safety profile (NCT00950300), and demonstrated a compelling patient (pt) preference for H SC (NCT01401166). IV pertuzumab (PERJETA®; P IV) + H IV + docetaxel (D IV) was also shown to significantly improve progression-free survival (PFS) and overall survival vs. placebo + H IV + D IV in HER2-positive metastatic BC (NCT00567190). Here we report results from the final analysis of MetaPHER (NCT02402712), the largest study to evaluate safety and tolerability of first-line H SC + P IV + D IV for HER2-positive metastatic/locally advanced BC. Earlier analyses have been reported (Kümmel SABCS 2016; P4-21-42; Kümmel ESMO 2018; 323P). Methods Pts were ≥18-year-old females who had received no previous systemic non-hormonal anticancer therapy for their disease, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and a left ventricular ejection fraction (LVEF) ≥50%. Brain metastases and concomitant hormone therapy were allowed. Pts received 600 mg H SC + 840 mg loading/420 mg maintenance doses of P IV + ≥6 cycles of D IV (75 mg/m2→100 mg/m2; &gt;6 cycles were given at the investigator’s discretion) every 3 weeks until disease progression, unacceptable toxicity, withdrawal of consent, death, or predefined study end. The primary objective was to evaluate safety and tolerability. Adverse events (AEs) were graded per National Cancer Institute - Common Terminology Criteria for Adverse Events version 4.0; left ventricular systolic dysfunction (LVSD) was classified according to the New York Heart Association Functional Classification system. Safety results are descriptive. Exploratory efficacy endpoints were PFS and objective response rate (ORR). Results Four hundred eighteen pts were enrolled; 412 were treated and analyzed for safety, and 160 remained on treatment at study end. Data cutoff was May 23, 2019 with median follow-up of 27 months (max. 45 months). Baseline demographics were similar to the interim analysis. Median cycles of H SC, P IV, and D IV were 22.0, 21.5, and 6.0, respectively (some discontinued P IV due to toxicity but remained on H SC per the protocol). Most pts experienced ≥1 any-grade AE (406; 98.5%); 221 (53.6%), grade ≥3 AEs; 107 (26.0%), serious AEs; 87 (21.1%), AEs leading to withdrawal from any study treatment; 87 (21.1%), investigator-reported administration-related and local injection-site reactions (21 [5.1%] H SC-related). There were 87 deaths (21.1% of pts): 73 (17.7%) from disease progression, nine (2.2%) due to AEs, and five (1.2%) due to other causes after treatment discontinuation. Three pts (0.7%) experienced grade ≥3 cardiac AEs, and one (0.2%) a serious AE suggestive of congestive heart failure. Of the 396 pts with LVEF measurements at baseline and ≥1 post-baseline visit, 40 (10.1%) had LVEF drops (to &lt;50% and ≥10% points from baseline; the majority were asymptomatic, grade 1-2, and did not lead to study drug discontinuation); only two (0.5%) had symptomatic LVSD. There were no cardiac deaths. Median investigator-assessed PFS was 18.7 months (234 events [56.8%]). The ORR was 75.6% (95% CI 70.6-80.1; 254/336 pts with measurable disease at baseline); the clinical benefit rate was 92.0% (309 pts). Conclusion The safety profile of first-line H SC + P IV + D IV for HER2-positive advanced BC was consistent with the known safety profile of H IV + P IV + D IV. No new safety signals were identified. Efficacy data were supportive of historical reports of H IV + P IV + D IV.

Citation Format: Sherko Kümmel, Carlo A Tondini, Jacinta Abraham, Zbigniew Nowecki, Bartosz Itrych, Erika Hitre, Bogusława Karaszewska, Alejandro Juarez, Flavia Morales-Vásquez, Jose Manuel Pérez García, Servando Cardona-Huerta, Mark Benyunes, Eleonora Restuccia, Adam Knott, Estefanía Monturus, Marco Sequi, Miguel Martín. Subcutaneous trastuzumab and hyaluronidase-oysk with intravenous pertuzumab and docetaxel in HER2-positive advanced breast cancer: Final analysis of the phase IIIb, multicenter, open-label, single-arm MetaPHER study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-05.

Electrochemotherapy in the Treatment of Breast Cancer Metastasis to the Skin and Subcutaneous Tissue - Multicenter Experience

INTRODUCTION

Breast cancer is responsible for more than 50% of cutaneous metastases. One of the treatment options is electrochemotherapy (ECT). It is an effective method of local tumor ablation through the application of electroporation. The primary objective of the study was to demonstrate a response to the treatment in our group of patients.

METHODS

Between February 2015 and October 2016, in 3 centers in Poland, 47 ECT procedures were performed in 38 patients with metastasis of breast cancer to the skin.

RESULTS

At 12 weeks after the procedures, 71% of patients showed a positive response to the treatment (42% with complete response, and 29% with partial response). Multivariate analysis demonstrated that only the estrogen receptor status and the size of the metastatic lesion were predictive of overall response (p = 0.0243 and p = 0.03716, respectively).

CONCLUSION

The results of our study demonstrate a high effectiveness of ECT in the treatment of cutaneous metastasis from breast cancer. This method, although used for palliative treatment, brings a significant improvement in the quality of life of patients.