Preventing alpelisib-related hyperglycaemia in HR+/HER2-/PIK3CA-mutated advanced breast cancer using metformin (METALLICA): a multicentre, open-label, single-arm, phase 2 trial

Background

Hyperglycaemia is an early and frequent adverse event during alpelisib treatment. METALLICA aimed to evaluate prophylactic metformin to prevent or reduce hyperglycaemia occurrence in patients with HR+/HER2-/PIK3CA-mutated advanced breast cancer (ABC).

Methods

Between August 13th, 2020 and March 23rd, 2022, this 2-cohort, phase 2, multicentre, single-arm trial (NCT04300790) enrolled patients with HR+/HER2-/PIK3CA-mutated ABC: cohort A, normal glycaemia (fasting plasma glucose <100 mg/dL [<5.6 mmol/L] and HbA1c <5.7%), and cohort B, prediabetes (fasting plasma glucose 100-140 mg/dL [5.6-7.8 mmol/L] and/or haemoglobin A1C [HbA1c] 5.7-6.4%). Participants were at least 18 years old, with Eastern Cooperative Oncology Group performance status of 0-1, and up to two prior lines of endocrine therapy (ET) for ABC. Alpelisib plus ET were administered in 28-day cycles after initiation of prophylactic metformin plus ET. Primary endpoint was the incidence of grade 3-4 hyperglycaemia over the first 8 weeks. Secondary endpoints included safety, progression-free survival (PFS), objective response rate (ORR), and clinical benefit rate (CBR). The primary objective for cohort A and B is met with ≤7 (14.6%) and ≤4 (20%) patients with grade 3-4 hyperglycaemia over the first 8 weeks, respectively.

Findings

233 patients were screened, and 68 (20.2%) patients were enrolled in cohorts A (n = 48) and B (n = 20). Median follow-up was 7.8 months (IQR 1.4-19.6). Over the first 8 weeks, one (2.1%) of 48 patients in cohort A (95% CI: 0.5-11.1; P < 0.0001), and three (15.0%) of 20 patients in cohort B (95% CI: 5.6-37.8; P = 0.016) had grade 3-4 hyperglycaemia. Serious treatment-related adverse events occurred in seven patients (10.3%). The most common were rash (two [2.9%]), vomiting (two [2.9%]), and diarrhoea (two [2.9%]). Discontinuation of alpelisib caused by AEs was reported in nine patients (13.2%), none caused by hyperglycaemia. At data cutoff (15 June, 2022), no treatment-related deaths were observed. In the full analysis set, median PFS was 7.3 months (95% CI: 5.9-not reached), ORR was 20.6% (95% CI: 11.7-32.1%), and CBR was 52.9% (95% CI: 40.4-65.2).

Interpretation

In HR+/HER2-/PIK3CA-mutated ABC, prophylactic metformin before alpelisib plus endocrine treatment has low incidence and severity of alpelicib-induced hyperglycaemia.

Funding

Novartis Pharmaceuticals.

Clinicopathological and molecular predictors of [18F]FDG-PET disease detection in HER2-positive early breast cancer: RESPONSE, a substudy of the randomized PHERGain trial

BACKGROUND

The PHERGain study (NCT03161353) is assessing early metabolic responses to neoadjuvant treatment with trastuzumab-pertuzumab and chemotherapy de-escalation using a [18Fluorine]fluorodeoxyglucose-positron emission tomography ([18F]FDG-PET) and a pathological complete response-adapted strategy in HER2-positive (HER2+) early breast cancer (EBC). Herein, we present RESPONSE, a PHERGain substudy, where clinicopathological and molecular predictors of [18F]FDG-PET disease detection were evaluated.

METHODS

A total of 500 patients with HER2 + EBC screened in the PHERGain trial with a tumor size > 1.5 cm by magnetic resonance imaging (MRI) were included in the RESPONSE substudy. PET[-] criteria entailed the absence of  ≥ 1 breast lesion with maximum standardized uptake value (SUVmax) ≥ 1.5 × SUVmean liver + 2 standard deviation. Among 75 PET[-] patients screened, 21 with SUVmax levels < 2.5 were randomly selected and matched with 21 PET[+] patients with SUVmax levels ≥ 2.5 based on patient characteristics associated with [18F]FDG-PET status. The association between baseline SUVmax and [18F]FDG-PET status ([-] or [+]) with clinicopathological characteristics was assessed. In addition, evaluation of stromal tumor-infiltrating lymphocytes (sTILs) and gene expression analysis using PAM50 and Vantage 3D™ Cancer Metabolism Panel were specifically compared in a matched cohort of excluded and enrolled patients based on the [18F]FDG-PET eligibility criteria.

RESULTS

Median SUVmax at baseline was 7.2 (range, 1-39.3). Among all analyzed patients, a higher SUVmax was associated with a higher tumor stage, larger tumor size, lymph node involvement, hormone receptor-negative status, higher HER2 protein expression, increased Ki67 proliferation index, and higher histological grade (p < 0.05). [18F]FDG-PET [-] criteria patients had smaller tumor size (p = 0.014) along with the absence of lymph node involvement and lower histological grade than [18F]FDG-PET [+] patients (p < 0.01). Although no difference in the levels of sTILs was found among 42 matched [18F]FDG-PET [-]/[+] criteria patients (p = 0.73), [18F]FDG-PET [-] criteria patients showed a decreased risk of recurrence (ROR) and a lower proportion of PAM50 HER2-enriched subtype than [18F]FDG-PET[+] patients (p < 0.05). Differences in the expression of genes involved in cancer metabolism were observed between [18F]FDG-PET [-] and [18F]FDG-PET[+] criteria patients.

CONCLUSIONS

These results highlight the clinical, biological, and metabolic heterogeneity of HER2+ breast cancer, which may facilitate the selection of HER2+ EBC patients likely to benefit from [18F]FDG-PET imaging as a tool to guide therapy.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT03161353; registration date: May 15, 2017.

Optimal [18F]FDG PET/CT Cutoff for Pathologic Complete Response in HER2-Positive Early Breast Cancer Patients Treated with Neoadjuvant Trastuzumab and Pertuzumab in the PHERGain Trial

The PHERGain trial investigated the potential of metabolic imaging to identify candidates for chemotherapy deescalation in human epidermal growth factor receptor 2 (HER2)-positive, invasive, operable breast cancer with at least 1 breast lesion evaluable by [18F]FDG PET/CT. [18F]FDG PET/CT responders were defined as patients with an SUVmax reduction (ΔSUVmax) of at least 40% in all of their target lesions after 2 cycles of trastuzumab and pertuzumab (HP) (with or without endocrine therapy). In total, 227 of 285 patients (80%) included in the HP arm showed a predefined metabolic response and received a total of 8 cycles of HP (with or without endocrine therapy). Pathologic complete response (pCR), defined as ypT0/isN0, was achieved in 37.9% of the patients. Here, we describe the secondary preplanned analysis of the best cutoff of ΔSUVmax for pCR prediction. Methods: Receiver-operating-characteristic analysis was applied to look for the most appropriate ΔSUVmax cutoff in HER2-positive early breast cancer patients treated exclusively with neoadjuvant HP (with or without endocrine therapy). Results: The ΔSUVmax capability of predicting pCR in terms of the area under the receiver-operating-characteristic curve was 72.1% (95% CI, 65.1-79.2%). The optimal ΔSUVmax cutoff was found to be 77.0%, with a 51.2% sensitivity and a 78.7% specificity. With this cutoff, 74 of 285 patients (26%) would be classified as metabolic responders, increasing the pCR rate from 37.9% (cutoff ≥ 40%) to 59.5% (44/74 patients) (P < 0.01). With this optimized cutoff, 44 of 285 patients (15.4%) would avoid chemotherapy in either the neoadjuvant or the adjuvant setting compared with 86 of 285 patients (30.2%) using the original cutoff (P < 0.001). Conclusion: In the PHERGain trial, an increased SUVmax cutoff (≥77%) after 2 cycles of exclusive HP (with or without endocrine therapy) achieves a pCR in the range of the control arm with chemotherapy plus HP (59.5% vs. 57.7%, respectively), further identifying a subgroup of patients with HER2-addicted tumors. However, the original cutoff (≥40%) maximizes the number of patients who could avoid chemotherapy.

3-year invasive disease-free survival with chemotherapy de-escalation using an 18F-FDG-PET-based, pathological complete response-adapted strategy in HER2-positive early breast cancer (PHERGain): a randomised, open-label, phase 2 trial

BACKGROUND

PHERGain was designed to assess the feasibility, safety, and efficacy of a chemotherapy-free treatment based on a dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab in patients with HER2-positive early breast cancer (EBC). It used an 18fluorine-fluorodeoxyglucose-PET-based, pathological complete response (pCR)-adapted strategy.

METHODS

PHERGain was a randomised, open-label, phase 2 trial that took place in 45 hospitals in seven European countries. It randomly allocated patients in a 1:4 ratio with centrally confirmed, HER2-positive, stage I-IIIA invasive, operable breast cancer with at least one PET-evaluable lesion to either group A, where patients received docetaxel (75 mg/m2, intravenous), carboplatin (area under the curve 6 mg/mL per min, intravenous), trastuzumab (600 mg fixed dose, subcutaneous), and pertuzumab (840 mg loading dose followed by 420 mg maintenance doses, intravenous; TCHP), or group B, where patients received trastuzumab and pertuzumab with or without endocrine therapy, every 3 weeks. Random allocation was stratified by hormone receptor status. Centrally reviewed PET was conducted at baseline and after two treatment cycles. Patients in group B were treated according to on-treatment PET results. Patients in group B who were PET-responders continued with trastuzumab and pertuzumab with or without endocrine therapy for six cycles, while PET-non-responders were switched to receive six cycles of TCHP. After surgery, patients in group B who were PET-responders who did not achieve a pCR received six cycles of TCHP, and all patients completed up to 18 cycles of trastuzumab and pertuzumab. The primary endpoints were pCR in patients who were group B PET-responders after two treatment cycles (the results for which have been reported previously) and 3-year invasive disease-free survival (iDFS) in patients in group B. The study is registered with ClinicalTrials.gov (NCT03161353) and is ongoing.

FINDINGS

Between June 26, 2017, and April 24, 2019, a total of 356 patients were randomly allocated (71 patients in group A and 285 patients in group B), and 63 (89%) and 267 (94%) patients proceeded to surgery in groups A and B, respectively. At this second analysis (data cutoff: Nov 4, 2022), the median duration of follow-up was 43·3 months (range 0·0-63·0). In group B, the 3-year iDFS rate was 94·8% (95% CI 91·4-97·1; p=0·001), meeting the primary endpoint. No new safety signals were identified. Treatment-related adverse events and serious adverse events (SAEs) were numerically higher in patients allocated to group A than to group B (grade ≥3 62% vs 33%; SAEs 28% vs 14%). Group B PET-responders with pCR presented the lowest incidence of treatment-related grade 3 or higher adverse events (1%) without any SAEs.

INTERPRETATION

Among HER2-positive EBC patients, a PET-based, pCR-adapted strategy was associated with an excellent 3-year iDFS. This strategy identified about a third of patients who had HER2-positive EBC who could safely omit chemotherapy.

FUNDING

F Hoffmann-La Roche.

Correlation between trophoblast cell-surface antigen-2 (Trop-2) expression and pathological complete response in patients with HER2-positive early breast cancer treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab

PURPOSE

The prognostic and predictive role of trophoblast cell-surface antigen-2 (Trop-2) overexpression in human epidermal growth factor receptor 2-positive (HER2-positive) breast cancer is currently unknown. We retrospectively analyzed Trop-2 expression and its correlation with clinicopathologic features and pathological complete response (pCR) in HER2-positive early breast cancer (EBC) patients treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab in the PHERGain study.

METHODS

Trop-2 expression at baseline was determined in formalin-fixed, paraffin-embedded primary tumor biopsies by immunohistochemistry and was first classified into expressing (Trop-2-positive) or not-expressing (Trop-2-negative) tumors. Then, it was classified by histochemical score (H-score) according to its intensity into low (0-9), intermediate (10-49), and high (≥ 50). The association between clinicopathologic features, pCR, and Trop-2 expression was performed with Fisher's exact test.

RESULTS

Forty-one patients with tissue evaluable for Trop-2 expression were included, with 28 (68.3%) Trop-2-positive tumors. Overall, 17 (41.46%), 14 (34.15%), and 10 (24.40%) tumors were classified as low, intermediate, and high, respectively. Trop-2 expression was significantly associated with decreased pCR rates (50.0% vs. 92.3%; odds ratio [OR] 0.05; 95% CI, 0.002-0.360]; p adjusted = 0.01) but was not correlated with any clinicopathologic features (p ≥ 0.05). Tumors with the highest Trop-2 H-score were less likely to obtain a pCR (OR 0.03; 95% CI, 0.001-0.290, p adjusted < 0.01). This association was confirmed in univariate and multivariate regression analyses.

CONCLUSION

These findings suggest a potential role of Trop-2 expression as a biomarker of resistance to neoadjuvant chemotherapy plus dual HER2 blockade and may become a strategic target for future combinations in HER2-positive EBC patients.

A single-arm study design with non-inferiority and superiority time-to-event endpoints: a tool for proof-of-concept and de-intensification strategies in breast cancer

De-escalation trials in oncology evaluate therapies that aim to improve the quality of life of patients with low-risk cancer by avoiding overtreatment. Non-inferiority randomized trials are commonly used to investigate de-intensified regimens with similar efficacy to that of standard regimens but with fewer adverse effects (ESMO evidence tier A). In cases where it is not feasible to recruit the number of patients needed for a randomized trial, single-arm prospective studies with a hypothesis of non-inferiority can be conducted as an alternative. Single-arm studies are also commonly used to evaluate novel treatment strategies (ESMO evidence tier B). A single-arm design that includes both non-inferiority and superiority primary objectives will enable the ranking of clinical activity and other parameters such as safety, pharmacokinetics, and pharmacodynamics data. Here, we describe the statistical principles and procedures to support such a strategy. The non-inferiority margin is calculated using the fixed margin method. Sample size and statistical analyses are based on the maximum likelihood method for exponential distributions. We present example analyses in metastatic and adjuvant settings to illustrate the usefulness of our methodology. We also explain its implementation with nonparametric methods. Single-arm designs with non-inferiority and superiority analyses are optimal for proof-of-concept and de-escalation studies in oncology.

Abstract P4-07-29: Olaparib plus Trastuzumab in HER2[+] BRCA-Mutated Advanced Breast Cancer Patients: The OPHELIA Study

Background: Olaparib (O) is approved for the treatment of HER2[-] patients (pts) with early or metastatic breast cancer and a germline BRCA mutation. Nevertheless, there is no evidence that HER2[+] tumors are resistant to PARPi. Preclinical data support that HER2[+] cells are sensitive to PARPi and strongly suggest that PARP inhibition augments the efficacy of trastuzumab (T). To test whether PARPi is synergistic with anti-HER2 therapy, the OPHELIA study has assessed the efficacy and safety of O in combination with T in pts with HER2[+] germinal BRCA-mutated advanced breast cancer (ABC). Methods: OPHELIA (NCT03931551) is an open-label, multicenter, single-arm, phase II trial. The study enrolled pts aged ≥18 years diagnosed of HER2[+] ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease (including a pertuzumab- or trastuzumab emtansine based regimen). Pts received O (300 mg oral, twice daily) plus T (either loading dose of 8 mg/kg IV infusion, and subsequent 3-weekly doses of 6 mg/kg IV infusion; or 600 mg SC injection, on day 1 of every 21-day cycle) until disease progression, unacceptable toxicity, or consent withdrawal. Primary endpoint was investigator-assessed clinical benefit rate (CBR) for at least 24 weeks as per RECIST v.1.1. Secondary endpoints included overall response rate (ORR), duration of response (DoR), progression-free survival (PFS), overall survival (OS); and safety and tolerability as per NCI-CTCAE v.5.0. The primary analysis evaluated CBR (H0: ≤5%; H1: ≥30%) based on exact binomial test. Sample size was designed to attain a 90% power at 10% one-sided alpha level. Results: From Mar 25, 2019, through Mar 2, 2022, 5 pts (from a total of 42 pts evaluated) were enrolled at 17 sites in Spain. Median age was 37.0 (range 32–54) years, 1 (20.0%) patient was male, 4 (80.0%) pts carried germinal BRCA2 mutations, 4 (80.0%) pts had received ≥ 3 advanced disease treatments lines, and 4 (80.0%) pts presented ≥ 2 metastatic sites. At data cutoff (Mar 2, 2022), with a median follow-up of 18.7 months (min: 11.7; max: 22.1), 40.0% of pts remained on therapy. CBR at 24 weeks was 80.0% meeting the primary endpoint (4 of 5 pts; 95% CI, 28.4% to 99.5%, p&lt; 0.001). ORR (1 complete and 2 partial responses) was 60.0% (95% CI, 17.4% to 94.7%), and median DoR was 3.8 months (95% CI, 2.5 to 8.3 months). Two (40.0%) pts had PFS events due to disease progression at 5.2 and 1.2 months, respectively. Rest of pts were treated for 5.5, 11.2, and 19.0 months. There were 2 (40.0%) deaths at 14.0 and 18.5 months. The most common non-hematological treatment emergent adverse events (TEAEs) of any grade (G) were fatigue (60.0%; 0% G≥3), nausea (60.0%; 0% G≥3), vomiting (40.0%; 0% G≥3), and back pain (40.0%; 0% G≥3). Anemia (40.0%; 20.0% G≥3) and lymphopenia (40.0%; 20.0% G≥3) were the most frequent hematological TEAEs. One (20.0%) patient discontinued treatment because of a drug-related TEAE (leukopenia). A dose reduction of O was reported in 1 (20.0%) patient. No treatment-related deaths were reported. Conclusions: HER2 overexpression in germline BRCA-mutated ABC is infrequent. The activity observed in these 5 pts indicates that O+T combination might be of help in this group of pts. We strongly believe that randomized data are not needed, and RWE studies might help us to understand the real activity of this combination. Toxicity was as expected.

Citation Format: José E. Alés-Martínez, Judith Balmaña, Pedro Sánchez-Rovira, Francisco Javier Salvador Bofill, José Ángel García-Sáenz, Isabel Pimentel, Serafin Morales Murillo, Adela Fernández, Ainhara Lahuerta Martínez, Neus Ferrer, Pilar Zamora, Begoña Bermejo, Tamara Díaz-Redondo, María Helena Lopez-Ceballos, María Galán, Andrea Malfettone, Laura Calabuig, Miguel Sampayo-Cordero, José Manuel Pérez-García, Javier Cortés, Antonio Llombart-Cussac. Olaparib plus Trastuzumab in HER2[+] BRCA-Mutated Advanced Breast Cancer Patients: The OPHELIA 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 P4-07-29.

Abstract PD13-10: PD13-10 Impact of Proton Pump Inhibitors (PPI) on Palbociclib (PAL) Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer (HR+/HER2- ABC): Exploratory Analysis of the PARSIFAL Trial

Background The use of PPI among cancer patients (pts) is quite frequent. PAL is an oral, cyclin-dependent kinase 4 and 6 inhibitor recommended to be taken under fed conditions. PAL showed a reduced solubility when gastric pH is &gt;4.5, a level commonly achieved by PPI. Observational, retrospective studies on concomitant PPI with PAL or ribociclib showed a shorter progression-free survival (PFS) among PPI users than nonusers. In the randomized, phase 2 PARSIFAL trial, PAL plus fulvestrant demonstrated no improvement in PFS and overall survival (OS) versus PAL plus letrozole as frontline treatment in HR+/HER2- ABC pts (Llombart-Cussac et al, JAMA Oncol 2021). Here we assessed the impact of PPI on PAL efficacy and safety in pts included in the PARSIFAL study. Methods Pts with endocrine-sensitive HR+/HER2- ABC and no prior therapy in advanced setting were randomly assigned to receive PAL (hard capsule formulation) plus either fulvestrant or letrozole. Pts with ≥1 PPI received over the entire PAL-based regimen were defined as PPI users, or PPI naïve (N-PPI) if no PPI was administered over the whole study treatment. We carried out two analyses considering early PPI users (E-PPI) –composed by pts who were receiving PPI since the PAL-based regimen initiation– and long-term PPI users (LT-PPI) –composed by pts who received PPI over the entire or ≥⅔ of the PAL-based regimen. PPI users defined as neither E-PPI nor LT-PPI were excluded from the analysis to avoid biases due to the PPI limited exposition. PFS, OS, and safety were compared among groups. Landmark analysis at 3, 6, 12, 18, 24, and 30 months (mo) was used for survival estimates conditional on surviving to certain time points and adjust for immortality bias in comparison between N-PPI and PPI users. Analyses were adjusted by stratification factors and patient characteristics. Results Of 486 pts included in the study, 325 (66.9%) were N-PPI. Among 161 (33.1%) PPI users, 64 (13.2%) were E-PPI and 91 (18.7%) were LT-PPI. Omeprazole was the most prescribed PPI in 80.7% (130 of 161) of PPI users. Median exposition to PPI for PPI users, E-PPI, and LT-PPI was 13.6, 15.9, and 19.4 mo, respectively. Compared with N-PPI, E-PPI and LT-PPI were older (median age, 60.5 vs 66.5 vs 67.0 years, respectively; P&lt; 0.001) and had a worse functional status (ECOG PS of 0, 60.0% vs 34.0% vs 43.0%, respectively; P=0.002). Median follow-up for the whole population was 32 mo. Median PFS was 28.7 mo in N-PPI compared with 23.0 mo in E-PPI (HR 1.5; 95%CI 1.1–2.2; P=0.024) and 23.0 mo in LT-PPI (HR 1.4; 95%CI 1.0–1.9; P=0.035). Both PPI groups had poorer median PFS than N-PPI by landmark analysis at 3 and 12 mo. Subgroup analysis showed a consistent trend regardless of endocrine partner. Three-year OS rate was 81.1% in N-PPI compared with 63.5% in E-PPI (HR 2.2; 95%CI 1.3–3.7; P=0.003) and 62.0% in LT-PPI (HR 2.1; 95%CI 1.4–3.4; P=0.001). Both PPI groups had poorer 3-year OS rate than N-PPI by landmark analysis at 3, 6, 12, and 18 mo. Grade ≥3 hematological adverse events (AEs) occurred in 71.7% (233 of 325 pts) of N-PPI compared with 57.8% (37 of 64 pts; P=0.021) of E-PPI and 54.9% (50 of 91 pts; P=0.003) of LT-PPI. Dose reductions and delays due to hematological AEs were reported in 70.8% (230 of 325 pts) of N-PPI compared with 56.3% (36 of 64 pts; P=0.018) of E-PPI and 52.7% (48 of 91 pts; P=0.002) of LT-PPI. At 3 mo, 45.8% (149 of 325 pts) of N-PPI required a dose reduction or delay due to hematological AEs compared with 39.1% (25 of 64 pts; P=0.42) of E-PPI. Conclusions Early and sustained coadministration of PPI with PAL and endocrine therapy were associated with lower efficacy, hematological toxicities, and dose modifications. Despite the post-hoc nature of the study, these findings suggest pharmacokinetic interactions between PPI and PAL capsules. Further confirmatory studies including the tablet formulation of PAL, which is expected to assure its optimal absorption, are needed.

Citation Format: Serena Di Cosimo, José Manuel Pérez-García, Meritxell Bellet Ezquerra, Florence Dalenc, Miguel Gil Gil, Manuel Ruiz Borrego, Joaquín Gavilá, Miguel Sampayo-Cordero, Elena Aguirre, Peter Schmid, Frederik Marmé, Joseph Gligorov, Andreas Schneeweiss, Joan Albanell, Pilar Zamora, Duncan Wheatley, Eduardo Martínez De Dueñas, Vicente Carañana, Kepa Amillano, Andrea Malfettone, Javier Cortés, Antonio Llombart-Cussac. PD13-10 Impact of Proton Pump Inhibitors (PPI) on Palbociclib (PAL) Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer (HR+/HER2- ABC): Exploratory Analysis of the PARSIFAL 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 PD13-10.

Abstract PD7-02: Trastuzumab Deruxtecan in patients with Unstable Central Nervous System Involvement from HER2-Low Advanced Breast Cancer: The DEBBRAH Trial

Background: The antibody-drug conjugate trastuzumab deruxtecan (T-DXd) significantly improved survival outcomes of HER2-low advanced breast cancer (ABC) patients (pts) compared to standard chemotherapy in the DESTINY-Breast04 trial. DEBBRAH is assessing the efficacy and safety of T-DXd in HER2[+] and HER2-low ABC pts with a history of brain metastases (BM) and/or leptomeningeal carcinomatosis (LMC); here, we report results of HER-low ABC pts. Methods: DEBBRAH (NCT04420598) is a multicenter, open-label, five-cohort, non-comparative, phase 2 study across 18 hospitals in 2 countries. A total of 39 pts aged ≥18 years with pretreated HER2[+] or HER2-low ABC with stable, progressing, or untreated BM and/or LMC, were enrolled in 5 cohorts: (1) HER2[+] ABC with non-progressing BM after radiotherapy and/or surgery; (2) HER2[+] or HER2-low ABC with asymptomatic untreated BM; (3) HER2[+] ABC with progressing BM after local treatment; (4) HER2-low ABC with progressing BM after local treatment; (5) HER2[+] or HER2-low ABC with LMC. Pts received 5.4 mg/kg T-DXd intravenously once every 21 days until disease progression, unacceptable toxicity, or consent withdrawal. Primary endpoint for cohorts 2 and 4 was intracranial overall response rate (ORR-IC) according to RANO-BM. Secondary endpoints included overall response (ORR) according to RECIST v1.1, progression-free survival (PFS), duration of response (DoR), clinical benefit rate (CBR); and safety and tolerability as per NCI-CTCAE v.5.0. Primary analysis is the estimation of ORR-IC (H0: ORR-IC ≤5%; H1: ORR-IC ≥40%) based on the one-sided binomial exact test. Sample size was planned to attain an 80% power at a nominal α level of 0.05 in each cohort. Results from cohort 2 should be considered descriptive since formal testing has to be performed in the whole cohort of pts with HER2[+] or HER2-low ABC and asymptomatic untreated BM. Results: From Oct 23, 2020, through Feb 15, 2022, 6 pts and 7 pts were allocated into cohorts 2 and 4, respectively. One patient with LMC included in cohort 4 was excluded from analysis. Median age was 54 (range 40–73) years. Median number of previous lines of therapy for advanced disease was 7 (range, 4-8) and 3 (range, 2-4) for cohorts 2 and 4, respectively. Median follow-up was 9.5 months (range, 1.6-15.7). At data cutoff (Apr 29, 2022), no patient of cohort 2 and 3 (50.0%) pts of cohort 4 remained on therapy. In cohort 2, ORR-IC was 66.7% (4 of 6 pts had intracranial partial response [PR]; 95% CI, 22.3–95.7). In cohort 4, ORR-IC was 33.3% meeting the primary endpoint (2 of 6 pts had intracranial PR; 95% CI, 4.3–77.7; P = .033). Overall, ORR-IC in all pts was 50% (6 of 12 pts; 95% CI, 21.1-78.9) and CBR was 66.7% (8 of 12 pts; 95% CI, 34.9-90.1). Combining pts with measurable intracranial or extracranial disease from cohorts 2 and 4, ORR, CBR and median DoR were 41.7% (5 of 12 pts; 95% CI, 15.2–72.3), 50.0% (6 of 12 pts; 95% CI, 21.1–78.9), and 7.2 months (95% CI, 2.5-16.4), respectively. Median PFS was 5.7 months (95% CI, 4.7-NA) among these pts. The most common treatment emergent adverse events (TEAEs) of any grade (G) were fatigue (58.3%; 8.3% G≥3) and nausea (50.0%; 0% G≥3). Two (16.7%; 0% G≥3) cases of interstitial lung disease/pneumonitis were reported. Serious unrelated TEAEs occurred in 2 (16.7%) of 12 pts; 1 case of general pain (G3) and 1 case of venous embolism (G5) that led to death. There were no drug-related deaths due to TEAEs. Conclusions: T-DXd showed a preliminary antitumor activity in pretreated HER2-low ABC pts with asymptomatic untreated or progressing BM after local treatment. The substantial response of BM to T-DXd in this setting is promising and warrants further investigation.

Citation Format: José Manuel Pérez-García, Marta Vaz Batista, Patricia Cortez-Castedo, Manuel Ruiz Borrego, Juan Miguel Cejalvo, Juan de la Haba-Rodríguez, Laia Garrigós, Fabriccio Racca, Sonia Servitja, Salvador Blanch, Maria Gión, Mónica Nave, Adela Fernández, Alejandro Martínez-Bueno, Antonio Llombart-Cussac, Miguel Sampayo-Cordero, Andrea Malfettone, Javier Cortés, Sofía Braga. Trastuzumab Deruxtecan in patients with Unstable Central Nervous System Involvement from HER2-Low Advanced Breast Cancer: The DEBBRAH 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 PD7-02.

Palbociclib Rechallenge for Hormone Receptor-Positive/HER-Negative Advanced Breast Cancer: Findings from the Phase II BioPER Trial

PURPOSE

To assess the efficacy and exploratory biomarkers of continuing palbociclib plus endocrine therapy (ET) beyond progression on prior palbociclib-based regimen in patients with hormone receptor-positive/HER2-negative (HR+/HER2-) advanced breast cancer (ABC).

PATIENTS AND METHODS

The multicenter, open-label, phase II BioPER trial included women who had experienced a progressive disease (PD) after having achieved clinical benefit on the immediately prior palbociclib plus ET regimen. Palbociclib (125 mg, 100 mg, or 75 mg daily orally for 3 weeks and 1 week off as per prior palbociclib-based regimen) plus ET of physician's choice were administered in 4-week cycles until PD or unacceptable toxicity. Coprimary endpoints were clinical benefit rate (CBR) and percentage of tumors with baseline loss of retinoblastoma (Rb) protein expression. Additional endpoints included safety and biomarker analysis.

RESULTS

Among 33 patients enrolled, CBR was 34.4% [95% confidence interval (CI), 18.6-53.2; P < 0.001] and 13.0% of tumors (95% CI, 5.2-27.5) showed loss of Rb protein expression, meeting both coprimary endpoints. Median progression-free survival was 2.6 months (95% CI, 1.8-6.7). No new safety signals were reported. A signature that included baseline mediators of therapeutic resistance to palbociclib and ET (low Rb score, high cyclin E1 score, ESR1 mutation) was independently associated with shorter median progression-free survival (HR, 22.0; 95% CI, 1.71-282.9; P = 0.018).

CONCLUSIONS

Maintaining palbociclib after progression on prior palbociclib-based regimen seems to be a reasonable, investigational approach for selected patients. A composite biomarker signature predicts a subset of patients who may not derive a greater benefit from palbociclib rechallenge, warranting further validation in larger randomized controlled trials.

Palbociclib with Fulvestrant or Letrozole in Endocrine-Sensitive Patients with HR-Positive/HER2-Negative Advanced Breast Cancer: A Detailed Safety Analysis of the Randomized PARSIFAL Trial

BACKGROUND

Palbociclib has gained a central role in the treatment of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Despite its manageable toxicity profile, venous thromboembolism (VTE) or interstitial lung disease (ILD)/pneumonitis may infrequently occur. Therefore, we provide a comprehensive summary of the safety and tolerability of the combination of endocrine therapy and palbociclib among patients included in the randomized phase 2 PARSIFAL study.

MATERIALS AND METHODS

Patients with endocrine-sensitive HR+/HER2- ABC and no prior therapy in an advanced setting (n = 486) were randomly assigned 1:1 to receive fulvestrant-palbociclib (FP) or letrozole-palbociclib (LP). Laboratory tests and the incidence of adverse events (AEs) were recorded at baseline and day 1 of each cycle. Progression-free survival (PFS) was estimated for patients with and without VTE.

RESULTS

A total of 483 patients were analyzed. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both groups. Febrile neutropenia occurred in 3 (1.2%) patients of the FP group and in 1 (0.4%) patient in the LP group. Six (2.5%; 0.4% grade 3) patients in the FP group and 6 patients (2.5%; 0.4% grade 3) in the LP group experienced ILD/pneumonitis. Pulmonary embolism was reported in 12 (5.0%) patients in the FP group and 6 (2.5%) patients in the LP group. Advanced age at baseline was the only factor significantly associated with an increased risk of pulmonary embolism (P < .01).

CONCLUSION

The PARSIFAL data confirmed the favorable safety profile of both palbociclib regimens. VTE and ILD/pneumonitis were occasionally reported, and their early detection allowed patients to continue treatment effectively without detriment to efficacy.

CLINICALTRIALS.GOV IDENTIFIER

NCT02491983; https://clinicaltrials.gov/ct2/show/NCT02491983).

Pembrolizumab in combination with tocilizumab in high-risk hospitalized patients with COVID-19 (COPERNICO): A randomized proof-of-concept phase II study

OBJECTIVES

Severe COVID-19 is associated with immune dysregulation and hyperinflammation (lymphocyte exhaustion and elevated interleukin 6. Pembrolizumab (P; immune-activating anti-programmed cell death-1 antibody) plus tocilizumab (TCZ; anti- interleukin 6 receptor antibody) might interrupt the hyperinflammation and restore cellular immunocompetence. We assessed the efficacy and safety of P + TCZ + standard of care (SOC) in high-risk, hospitalized patients with COVID-19 pneumonia without mechanical ventilation.

METHODS

Randomized, controlled, open-label, phase II trial in patients with severe SARS-CoV-2 infection to assess the hospitalization period to discharge.

RESULTS

A total of 12 patients were randomized (P + TCZ + SOC, n = 7; SOC, n = 5). Nine (75%) were males, with a median age of 68 (41-79) years. The median time to discharge for P + TCZ + SOC and SOC was 10 and 47.5 days (P = 0.03), with zero (n = 1 patient had P-related grade 5 myositis) and two COVID-19-related deaths, respectively.

CONCLUSION

The addition of P and TCZ to SOC reduced the hospitalization period, with higher and faster discharges without sequelae than SOC alone.

Trastuzumab and pertuzumab without chemotherapy in early-stage HER2+ breast cancer: a plain language summary of the PHERGain study

WHAT IS THIS SUMMARY ABOUT?

This is a summary of a publication about the PHERGain study, which was published in The Lancet Oncology in May 2021. The study includes 376 women with a type of breast cancer called HER2-positive breast cancer that can be removed by surgery. In the study, researchers wanted to learn if participants could be treated with two medicines called trastuzumab and pertuzumab without the need for chemotherapy. To identify HER2-positive tumors with more sensitivity to anti-HER2 therapies, the researchers used a type of imaging called a FDG-PET scan to check how well the treatments were working.

WHAT HAPPENED IN THE PHERGAIN STUDY?

Participants took a treatment before surgery, consisting of either chemotherapy (docetaxel and carboplatin) plus trastuzumab and pertuzumab (group A) or trastuzumab and pertuzumab alone (plus hormone therapy if the tumor was hormone receptor-positive; group B). After two cycles of treatment, participants underwent a FDG-PET scan. Participants assigned to group A completed 6 cycles of treatment regardless of ¹⁸F-FDG-PET results. Participants in group B continued the same treatment until surgery if their FDG-PET scan showed the treatment was working. While participants who did not show a response started treatment with chemotherapy in addition to trastuzumab and pertuzumab. All participants then had surgery.

WHAT WERE THE RESULTS?

The results revealed that, of the participants in group B who showed a response using FDG-PET scan, 37.9% achieved a disappearance of all invasive cancer in the breast and axillary lymph nodes. This rate appears to be higher than those reported in previous studies evaluating the same treatment. These participants also had less side effects and improved overall quality of life compared with participants taking chemotherapy plus trastuzumab and pertuzumab.

WHAT DO THE RESULTS OF THE STUDY MEAN?

Early monitoring of how well participants respond to treatment by FDG-PET scan seems to identify participants with operable HER2-positive breast cancer who were more likely to benefit from trastuzumab and pertuzumab without the need to have chemotherapy. The PHERGain study is still ongoing and results on long-term survival are expected to be released in 2023. Clinical Trial Registration: NCT03161353 (ClinicalTrials.gov).

Radium-223 for patients with metastatic castration-resistant prostate cancer with asymptomatic bone metastases progressing on first-line abiraterone acetate or enzalutamide: A single-arm phase II trial

PURPOSE

The paper aims to evaluate the efficacy and safety of ²²³Ra in patients who progressed after first-line androgen deprivation therapy.

PATIENTS AND METHODS

EXCAAPE (NCT03002220) was a multicentre, single-arm, open-label, non-controlled phase IIa trial in 52 patients with metastatic castration-resistant prostate cancer and asymptomatic bone metastases who have progressed on abiraterone acetate or enzalutamide, up to six doses of ²²³Ra (55 kBq/kg of body weight per month). The primary end-point was radiographic progression-free survival (rPFS). Secondary end-points included rPFS based on androgen receptor splice variant 7 (AR-V7) expression in circulating tumour cells (CTCs), overall survival, and safety.

RESULTS

Median rPFS was 5.5 months (95% CI 5.3-5.5). Median rPFS of patients with AR-V7(-) CTCs was longer than that of patients with AR-V7(+) CTCs (5.5 versus 2.2 months, respectively; P = 0.056). Median overall survival was 14.8 months (95% CI 11.2-not reached) and was significantly greater for AR-V7(-) patients than for AR-V7(+) patients (14.8 months versus 3.5 months, respectively; P < 0.01). ²²³Ra was well tolerated; anaemia and thrombocytopenia were the most common grade 3/4 adverse events (5.8% and 11.5%, respectively).

CONCLUSIONS

²²³Ra seems to be a reasonable treatment for patients with metastatic castration-resistant prostate cancer and asymptomatic bone metastases progressing on novel hormonal therapy and had an acceptable safety profile.

Safety interim analysis (SIA) of atractib: A phase 2 trial of first-line (1L) atezolizumab (A) in combination with paclitaxel (P) and bevacizumab (B) in metastatic triple-negative breast cancer (mTNBC)

1084

Background: A substantial benefit from adding an immune checkpoint inhibitor to chemotherapy (CT) was reported in mTNBC patients (pts) with PD-L1+ tumors. However, many pts still have a poor outcome. ATRACTIB is exploring the synergism between A (anti-PD-L1 antibody) and B (a VEGF-targeted antibody) with P in mTNBC irrespective of PD-L1 status. We report results from protocol-specified SIA. Methods: ATRACTIB is an open-label, single-arm, phase 2 trial (NCT04408118). Pts aged ≥18 years, with unresectable locally advanced or mTNBC, ECOG performance status of 0–1, who had received no prior systemic therapy or ≥12 months since (neo)adjuvant taxane-based CT are eligible. Pts receive A (840 mg IV, days 1, 15) with P (90 mg/m2 IV, days 1, 8, 15), and B (10 mg/kg IV, days 1, 15) on each 28-day cycle until disease progression, unacceptable toxicity, or patient withdrawal. Primary endpoint is investigator-assessed progression-free survival (PFS) as per RECIST v.1.1. Secondary endpoints include objective response and clinical benefit rates, overall survival, and safety. The trial was designed to detect a treatment effect in terms of median PFS (H0: ≤7 months; H1: ≥9.5 months) and 100 pts are needed to attain 80% power at a nominal one-sided α level of 5%. One SIA was planned for evaluating safety as per CTCAE v.5.0 on the first 20 pts who had completed a 3-month follow-up or reached the end of study. Results: From Oct 5, 2020, through Nov 21, 2021, 34 pts were enrolled at 13 sites in Spain and Germany and received at least 1 dose of study treatment. Median age was 57.5 (range 40–84) years, 23 (67.6%) pts had received prior CT for early disease, and 19 (56.0%) had visceral disease. At data cutoff (Sep 30, 2021), 25 (71.4%) pts were still receiving the drug regimen. Adverse events (AEs) led to drug discontinuation in 3 (8.8%) pts. Mean relative dose intensity was 90.2% for A, 96.5% for P, and 95.7% for B. P dose reduction was reported in 7 (20.6%) pts. Five (14.7) pts required a dose delay due to AEs (11.8% for A, 11.8% for P, and 8.8% for B). The most common AEs of any grade (G) were fatigue (47.1%; 8.8% G≥3), diarrhea (38.2%; 0% G≥3), and neurotoxicity (35.3%; 8.8% G≥3). Anemia (20.6%; 0% G≥3) and neutropenia (17.6%; 8.8% G≥3) were the most frequent hematological AEs. AEs of clinical interest (AECI) for B were hypertension (17.6%; 5.9% G≥3) and pulmonary embolism (2.9%; 0% G≥3). AECI for A were pneumonitis (2.9%; 0% G≥3), autoimmune hepatitis (2.9%; 2.9% G≥3), and alanine aminotransferase increased (2.9%; 2.9% G≥3). No treatment-related deaths were reported. Conclusions: The addition of A to P and B as 1L therapy for mTNBC shows a tolerable safety profile which is consistent with known safety profile of each agent without a significant synergistic toxicity. Based on the independent data monitoring committee recommendation, patient recruitment is ongoing. Clinical trial information: NCT04408118.

Trastuzumab deruxtecan in patients with central nervous system involvement from HER2-positive breast cancer: The DEBBRAH trial

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has shown durable antitumor activity in pretreated patients with HER2-positive advanced breast cancer (ABC), but its efficacy has not yet been evaluated in patients with active brain metastases (BMs). DEBBRAH aims to assess T-DXd in patients with HER2-positive or HER2-low ABC and central nervous system involvement.

METHODS

This ongoing, five-cohort, phase II study (NCT04420598) enrolled patients with pretreated HER2-positive or HER2-low ABC with stable, untreated, or progressing BMs, and/or leptomeningeal carcinomatosis. Here, we report findings from HER2-positive ABC patients with non-progressing BMs after local therapy (n = 8; cohort 1), asymptomatic untreated BMs (n = 4; cohort 2), or progressing BMs after local therapy (n = 9; cohort 3). Patients received 5.4 mg/kg T-DXd intravenously once every 21 days. The primary endpoint was 16-week progression-free survival (PFS) for cohort 1 and intracranial objective response rate (ORR-IC) for cohorts 2 and 3.

RESULTS

As of October 20, 2021, 21 patients received T-DXd. In cohort 1, 16-week PFS rate was 87.5% (95%CI, 47.3-99.7; P < .001). ORR-IC was 50.0% (95%CI, 6.7-93.2) in cohort 2 and 44.4% (95%CI, 13.7-78.8; P < .001) in cohort 3. Overall, the ORR-IC in patients with active BMs was 46.2% (95%CI, 19.2-74.9). Among patients with measurable intracranial or extracranial lesions at baseline, the ORR was 66.7% (12 out of 18 patients; 95%CI, 41.0-86.7), 80.0% (95%CI, 28.4-99.5) in cohort 1, 50.0% (95%CI, 6.7-93.2) in cohort 2, and 66.7% (95%CI, 29.9-92.5) in cohort 3. All responders had partial responses. The most common adverse events included fatigue (52.4%; 4.8% grade ≥3), nausea (42.9%; 0% grade ≥3), neutropenia (28.6%; 19% grade ≥3), and constipation (28.6%; 0% grade ≥3). Two (9.5%) patients suffered grade 1 interstitial lung disease/pneumonitis.

CONCLUSIONS

T-DXd showed intracranial activity with manageable toxicity and maintained the quality of life in pretreated HER2-positive ABC patients with stable, untreated, or progressing BMs. Further studies are needed to validate these results in larger cohorts.

A randomized phase 2 trial to evaluate the antitumor activity of enzalutamide (EZ) and talazoparib (TALA) for the treatment of metastatic hormone-naïve prostate cancer (mHNPC): ZZFIRST

TPS209

Background: Multiple lines of evidence suggest a crosstalk between androgen receptor (AR) signaling and DNA damage repair (DDR) in prostate cancer. Co-targeting both pathways in mHNPC can result in a clinically relevant synergistic effect. ZZFIRST trial is evaluating the combination of TALA –a poly(ADP-ribose) polymerase inhibitor– and EZ –an AR signaling inhibitor– in mHNPC patients. Methods: This is a multicenter, open-label, randomized, investigator-initiated phase 2 clinical trial. Men aged ≥18 years with histologically confirmed mHNPC, an ECOG performance status of 0-1, and a prostate-specific antigen (PSA) ≥4 ng/mL at enrolment are eligible. Patients must have not received previous systemic treatment for locally advanced or mHNPC. A total of 54 patients will start treatment with EZ 160 mg/day for 2 28-day cycles in addition to standard androgen-deprivation therapy (ADT). Patients are then randomized and stratified based on homologous recombination gene alterations on a 1:2 ratio to either continue EZ 160 mg/day, or to receive EZ 160 mg/day plus TALA 0.5 mg/day. In both arms, patients will continue ADT throughout the trial. Treatment will continue until progressive disease (PD) or unacceptable toxicity. PSA will be determined every 4 weeks and radiological tumor extend will be assessed at screening and every 8 weeks for the 6 initial months of treatment and every 12 weeks thereafter until PD. Primary endpoint is PSA-complete response defined as the percentage of patients with PSA < 0.2 ng/mL at 12 months of therapy. Secondary endpoints include PSA-complete response at any time point and at month 7, PSA response ( < 4 ng/ml) at 7 and 12 months, PSA-progression-free survival (PSA-PFS), radiologic PFS, time to castration resistance based on PSA-PFS and rPFS, and overall survival. Safety will be assessed as per NCI-CTCAE 5.0. Exploratory endpoints include analysis of transcriptional changes in AR and DDR pathways and assessment of genomic signatures on tumor and liquid biopsies collected at baseline, 4 weeks, and PD. An imaging sub-study of whole-body diffusion weighted MRI will help to further study antitumor activity and drug resistance mechanisms. This trial was opened to accrual in July 2020. Currently 44 patients have been enrolled (with 37 randomized by cycle 3 day 1) out of 54 expected. Analysis will be assessed with the exact binomial test. At least 11 patients must maintain PSA < 0.2 ng/mL by 12 months of therapy among 32 evaluable patients in the combination arm to justify further investigation of this strategy. A drop-out rate of 10% has been considered. Clinical trial information: NCT04332744.

A phase 2 study of the efficacy and safety of INCMGA00012 in advanced penile squamous cell carcinoma (PSqCC): ORPHEUS

TPS8

Background: PSqCC is a rare tumor with poor prognosis and limited therapeutic options. The current standard of care for advanced disease has been palliative platinum-based chemotherapy, with only marginal survival benefit. Recent data has shown that the majority of PSqCC patients present high levels of programmed death-ligand 1 (PD-L1). The ORPHEUS trial is evaluating the efficacy and safety of INCMGA00012 –a programmed cell death 1 (PD-1) antagonist– in patients with unresectable, locally advanced or metastatic PSqCC. Methods: ORPHEUS is an international, multicenter, open-label, single-arm, phase 2 clinical trial. Eligible patients are male aged ≥18 years with locally advanced or metastatic PSqCC, ECOG performance status of 0-1, adequate organ function, a life expectancy of ≥12 weeks, and with no prior treatment with PD-1 or PD-L1/2 agents. A total of 18 patients will be enrolled to receive INCMGA00012 500 mg administered intravenously on day 1 of each 28-day cycle. Treatment will continue until progressive disease or unacceptable toxicity. Tumor assessments per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and immune-related RECIST will be performed approximately every 8 weeks for the first 6 months and every 12 weeks thereafter until progressive disease. The primary endpoint is objective response rate. Secondary objectives include additional efficacy outcomes (clinical benefit rate, progression-free survival (PFS), 6-month PFS, duration of response, time to progression, overall survival, and maximum tumor shrinkage) and safety evaluated as per NCI-CTCAE 5.0. Exploratory objectives will evaluate efficacy based on immune-related RECIST; predictive and prognostic biomarkers; impact of INCMGA00012 on human immunodeficiency virus (HIV) control in patients known to be HIV-positive. The sample size calculation is based on an exact binomial test. At least 4 responders (22.2%) among 18 patients will be adequate to justify further investigation of this strategy. The analyses were designed to attain an 80% power, with a 10% dropout rate assumption, at a nominal one-sided α level of 5%. The response probabilities for null (H0) and alternative hypotheses (H1) were H0: ≤ 5% and H1: ≥ 25%, respectively. All 18 planned patients have been enrolled since the trial began in March 2020. Clinical trial information: NCT04231981.

Abstract OT1-12-07: A phase 2 study of chemotherapy de-escalation using a pathological response-guided strategy in patients with HER2-positive, low-risk early breast cancer: PHERGain-2

Background: The introduction of trastuzumab (H) and pertuzumab (P) and ado-trastuzumab emtansine (T-DM1) has drastically improved clinical outcomes in patients (pts) with HER2-positive early breast cancer, allowing to explore chemotherapy-sparing approaches in this population. PHERGain trial is evaluating the efficacy of dual HER2-blockade with HP as both neoadjuvant and adjuvant treatment using an 18F-fluorodeoxyglucose-PET-based and a pathological response-adapted strategy [Pérez-García JM et al., Lancet Oncol. 2021;22:858-871]. PHERGain-2 study is an additional step forward and aims to assess the feasibility of chemotherapy de-escalation with neoadjuvant HP followed by adjuvant HP or T-DM1 using a pathological response-adapted strategy in low-risk HER2-positive early breast cancer pts. Trial Design: PHERGain-2 is a multicenter, open-label, non-comparative, phase 2 trial. Eligible participants are patients aged ≥18 years with previously untreated, centrally confirmed, HER2-positive (immunohistochemical score 3+), invasive, node-negative breast cancer (&gt;0.5 and &lt;2.5 cm in tumor size). Eastern Cooperative Oncology Group performance status of 0 or 1, left ventricular ejection fraction of at least 55%, and adequate organ function are also required. Pts will receive the fixed-dose combination of HP for subcutaneous injection (1200 mg P plus 600 mg H loading dose, followed by 600 mg P plus 600 mg H maintenance doses) administered every 3 weeks for 8 cycles as neoadjuvant treatment. Hormone receptor-positive pts will be additionally given letrozole (2.5 mg/day orally) if postmenopausal or tamoxifen (20 mg/day orally) plus gonadotropin-releasing hormone analogue if pre-/peri-menopausal or men. Centrally reviewed MRI will be performed at screening and within 2 weeks prior to surgery. Surgery will be done within 4 weeks after the last dose of study treatment. After surgery, pts who achieve a pathologic complete response in breast and axilla (ypT0/is, ypN0) will continue HP for a total of 18 cycles; pts with residual invasive breast disease and/or ypN0(i+/mol+), ypN1mi will receive T-DM1 for 10 cycles; and pts with ypN1-3 will receive T-DM1 for 10 cycles and, at investigator’s discretion, chemotherapy before starting T-DM1. Adjuvant endocrine therapy and radiotherapy will be administered as per hormone receptor status and institutional practices. The primary efficacy and safety endpoints are 3-year recurrence-free interval (RFI) as per STEEP criteria and patient-reported outcomes after 1 year from neoadjuvant treatment initiation as measured by the EORTC-QLQ-C30 scale in the overall population. Key secondary endpoints include pathologic complete response, residual cancer burden, breast-conserving surgery rate; 3-year and 5-year event-free survival, relapse-free survival, distant relapse-free survival, disease-free survival, invasive disease-free survival, breast cancer-specific survival, overall survival; and safety and tolerability as per CTCAE 5.0. A total of 393 pts will be enrolled. The sample size was calculated with the log-minus-log Kaplan-Meier method. The analysis will test the null hypothesis that the 3-year RFI rate is ≤94% and the alternative hypothesis that 3-year RFI rate is ≥98%. With the expectation a 20% dropout rate, a sample size of 393 pts is necessary to attain 80% power at nominal level of two-sided alpha of 0.05. The analysis for the primary efficacy and safety endpoints will be conducted with 95% confidence intervals based on Kaplan-Meier estimator. This trial was opened to accrual in May 2021.

Citation Format: José Manuel Pérez-García, Ángel Guerrero-Zotano, Jacques Medioni, Andreas Schneeweiss, Marco Colleoni, Miguel Sampayo-Cordero, Andrea Malfettone, Javier Cortés, Antonio Llombart-Cussac. A phase 2 study of chemotherapy de-escalation using a pathological response-guided strategy in patients with HER2-positive, low-risk early breast cancer: PHERGain-2 [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 OT1-12-07.

Abstract P5-13-30: Analysis of αβ and γδ circulating T cells in the PHERGain randomized phase 2 trial for patients with HER2-positive early breast cancer receiving neoadjuvant trastuzumab and pertuzumab without chemotherapy: LINGain

Background: The presence of stromal tumor-infiltrating lymphocytes (TILs) represents an independent prognostic factor in HER2-positive early-stage breast cancer (EBC) treated with trastuzumab/pertuzumab-containing regimens. Among distinct subsets of TILs, conventional CD8+ αβ T cells require TCR signaling as a part of adaptive immunity, while γδ T cells display also innate-like activity via the NKG2D receptor contributing to a very rapid tumor immunosurveillance. Specific γδ T cell subsets were associated with remission and improved overall survival of patients with triple-negative breast cancer. However, very little is known about circulating αβ and γδ T cells and their immunological status in HER2-positive breast cancer. In this substudy, we aimed to characterize the αβ and γδ T cell subsets and the association with clinical outcome in peripheral blood of patients with HER2-positive EBC enrolled in the PHERGain trial, which assessed the possibility of chemotherapy de-escalation with neoadjuvant dual HER2 blockade with trastuzumab and pertuzumab using an 18F-fluorodeoxyglucose-PET and pathological response-adapted strategy. Methods: Peripheral blood was obtained from 24 consecutive patients who were assigned to the trastuzumab and pertuzumab group (+/- endocrine therapy as per hormone receptor status) before randomization (baseline) and after 2 treatment cycles (6 weeks). Blood samples were also collected from 48 age-matched healthy donors who represented the control group. Absolute numbers of CD3+, CD3+/CD4+, CD3+/CD8+, and CD3+/CD56+ according to the TCR expression, and annexin V apoptotic rate on αβ and γδ T cells were evaluated by flow cytometry. Subset distribution of T cell differentiation within naïve, central memory, effector memory, and terminally differentiated effector memory cells was also determined. The changes in the frequency of peripheral T cells and rate of apoptotic subsets between timepoints, patients, and healthy donors were compared with Wilcoxon test. The analyses were set at two-sided 0.05 level of significance. Results: Among 24 patients with evaluable blood samples at both timepoints, median age was 50.5 years (IQR 45.8-61), 45.8% had node-positive disease, 79.2% had hormone receptor-positive status, 79.2% had tumors with HER2 IHC 3+ status, and 54.2% achieved a pathological complete response (ypT0/is ypN0) after treatment. At baseline, levels of αβ and γδ T cells in EBC patients were significantly lower than levels in healthy subjects (P ≤0.05). After 6 weeks of study treatment, these levels in EBC patients did not significantly differ from those at baseline. Baseline rates of apoptotic subsets were higher in EBC patients than rates in healthy subjects (P &lt;0.01), but after 6 weeks of study treatment all apoptotic subsets were significantly reduced in EBC patients compared with those at baseline (P ≤0.05). No evidence of association was found between peripheral T cells and pathological complete response in EBC patients. Conclusions: These data suggest a potential involvement of T cell apoptosis on the mechanism of action mediated by dual HER2 blockade with trastuzumab and pertuzumab in patients with HER2-positive EBC. However, further validation is required. Additional data on the subset distribution of T cell differentiation status will be presented at the meeting.

Citation Format: Juan Carlos Andreu-Ballester, José Manuel Pérez-García, Begoña Bermejo, Vicente Carañana, Vega Iranzo, Joaquín Gavilà, Ana Santaballa, María Carmen Gómez-Soler, Miguel Sampayo-Cordero, Andrea Malfettone, Javier Cortes, Antonio Llombart-Cussac. Analysis of αβ and γδ circulating T cells in the PHERGain randomized phase 2 trial for patients with HER2-positive early breast cancer receiving neoadjuvant trastuzumab and pertuzumab without chemotherapy: LINGain [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 P5-13-30.

Abstract PD4-06: Trastuzumab deruxtecan in patients with HER2[+] or HER2-low-expressing advanced breast cancer and central nervous system involvement: Preliminary results from the DEBBRAH phase 2 study

Background: Approximately 30% to 40% of patients (pts) with HER2[+] advanced breast cancer (ABC) will develop brain metastases (BM) during the course of their disease. Trastuzumab deruxtecan (T-DXd; DS-8201) is an antibody-drug conjugate containing an anti-HER2 antibody, a cleavable tetrapeptide-based linker, and a topoisomerase I inhibitor payload. In the phase 2 DESTINY-Breast01 trial, T-DXd showed efficacy in the subgroup of HER2[+] ABC pts with stable BM at baseline. DEBBRAH is assessing the efficacy and safety of T-DXd in HER2[+] and HER2-low-expressing ABC pts with a history of BM and/or leptomeningeal carcinomatosis (LMC). Here, we report primary results from cohorts A and C. Methods: This is an ongoing, multicenter, open-label, 5-cohort, non-comparative, phase 2 study across 18 hospitals in 2 countries. A total of 39 pts aged ≥18 years with pretreated HER2[+] or HER2-low-expressing ABC with stable, progressing, or untreated BM and/or LMC are being enrolled in 5 cohorts: (A) HER2[+] ABC with non-progressing BM after radiotherapy and/or surgery; (B) HER2[+] or HER2-low-expressing ABC with asymptomatic untreated BM; (C) HER2[+] ABC with progressing BM after local treatment; (D) HER2-low-expressing ABC with progressing BM after local treatment; (E) HER2[+] or HER2-low-expressing ABC with LMC. In cohorts A and C, pts must have received prior taxane and ≥1 HER2-targeted therapy for ABC. Pts received 5.4 mg/kg T-DXd intravenously on day 1 of a 21-day cycle until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint for cohort A is 16-week progression-free survival (PFS) per local assessment using RANO-BM for central nervous system (CNS) lesions and RECIST v.1.1 for extracranial lesions (H0: 5%); for cohort C, CNS overall response rate (ORR; H0: 10%). A single-arm binomial design is used for cohorts A and C. A futility interim analysis has been planned in cohort A after accrual of 4 pts. Sample size was planned to attain an 80% power at nominal level of one-sided α of 0.05 in each cohort. Results: Between Jun 29, 2020, and Feb 18, 2021, 26 pts were allocated in the study. Enrollment is complete in cohorts A (n=8 pts) and C (n=9 pts), and ongoing in the remaining cohorts. At data cutoff (May 21, 2021), median follow-up for the cohort A was 5.5 months (IQR 4.4-6.9) and 6.2 months (IQR 5.1-6.4) for the cohort C. In the cohort A, 6 (75.0%) of 8 pts were alive without disease progression at 16 weeks, reaching the primary endpoint (p&lt;0.01). In the cohort C, the CNS ORR was 55.6% (5 pts with partial response), also meeting the primary endpoint (p&lt;0.01). At the time of this analysis, 75.0% of pts of the cohort A and 55.6% of the cohort C remained on therapy. The most frequent adverse events of any grade in 26 pts who received at least 1 dose of T-DXd were fatigue (11 [42.3%]; 3.8% of grade 3), nausea (10 [38.5%]), a decreased neutrophil count (9 [34.6%]; 11.5% of grade 3), and anemia (6 [23.1%]). Treatment-related serious adverse events occurred in 1 (3.8%) of 26 pts due to grade 1 pneumonitis. No treatment-related deaths were reported. Conclusions: T-DXd demonstrated preliminary efficacy with manageable toxicity in pretreated pts with HER2[+] ABC with stable and progressing BM after local treatment. Further investigation is required in larger cohorts to validate these findings. The assessment of the T-DXd antitumor activity in cohorts B, D, and E is currently ongoing.

Citation Format: Marta Vaz Batista, Patricia Cortez, Manuel Ruiz, Juan Miguel Cejalvo, Juan de la Haba, Laia Garrigós, Fabricio Racca, Sonia Servitja, Salvador Blanch, Iris Teruel, José Manuel Pérez-García, María Gion, Monica Nave, Antonio Llombart-Cussac, Miguel Sampayo-Cordero, Andrea Malfettone, Javier Cortes, Sofia Braga. Trastuzumab deruxtecan in patients with HER2[+] or HER2-low-expressing advanced breast cancer and central nervous system involvement: Preliminary results from the DEBBRAH phase 2 study [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 PD4-06.

Abstract OT2-19-06: Phase 2 study of abemaciclib in combination with endocrine therapy with or without paclitaxel induction in patients with hormone receptor-positive, HER2-negative advanced breast cancer and aggressive disease criteria: ABIGAIL

Background: Endocrine therapy (ET) is the preferred therapy option for patients (pts) with hormone receptor-positive (HR[+]) advanced breast cancer (ABC), except for pts with visceral crisis who often receive chemotherapy to achieve rapid symptom control. Cyclin-dependent kinases 4/6 inhibitors have improved the effectiveness of ET across all subgroups of pts with ABC by targeting potential mechanisms of resistance. An exploratory analysis revealed that the addition of abemaciclib to ET conferred the largest benefit in pts with poor prognostic characteristics (liver metastases, high grade tumors, or progesterone receptor-negative status) [Di Leo, NPJ Breast Cancer 2018; 4: 41]. ABIGAIL aims to provide consistent evidence that abemaciclib plus ET is superior or non-inferior to paclitaxel in terms of early overall response as first-line regimen in HR[+], HER2-negative ABC pts with poor prognosis. Trial Design: This is a multicenter, randomized, open-label, phase 2 trial. Eligible participants are men and women of any menopausal status aged ≥18 years with HR[+], HER2-negative ABC who had no prior systemic therapy in the advanced setting and at least one of the following aggressive disease criteria: (i) Visceral disease; (ii) High histological grade and/or progesterone receptor-negative status; (iii) Lactate dehydrogenase &gt;1.5 × the upper limit of normal; (iv) Relapse while on or within 36 months of completing adjuvant ET. Eastern Cooperative Oncology Group performance status of 0 or 1, measurable disease as per RECIST 1.1, and adequate organ function are also required. A total of 160 pts will be randomly assigned (1:1) to receive abemaciclib (300 mg/day orally during each 28-day cycle) plus ET as per investigator’s criteria (either letrozole [2.5 mg/day orally] or fulvestrant [500 mg intramuscularly on days 1, 15 of cycle 1, and on day 1 thereafter], or paclitaxel (90 mg/m² intravenously on days 1, 8, 15). Men and pre-/peri-menopausal women will receive a gonadotropin-releasing hormone agonist if randomized to abemaciclib plus ET. At investigator’s discretion, pts in the paclitaxel arm could receive abemaciclib plus ET at any point after the first 12 weeks or extend chemotherapy for a total of 6 cycles. Randomization will be stratified according to the presence of visceral disease and endocrine therapy. The primary endpoint is 12-week overall response rate (ORR) as per RECIST 1.1. Key secondary endpoints include ORR, clinical benefit rate, 12-week progression-free survival, progression-free survival, time to response, duration of response, overall survival, time to first subsequent therapy, time to second subsequent therapy, and time to first chemotherapy for pts in abemaciclib plus ET arm, patient-reported outcomes, and safety as per NCI-CTCAE 5.0. The sample size assumes the comparison of two proportions in an asymptotical normal test. We expect that 12-week ORR will be higher in the abemaciclib plus ET arm than paclitaxel arm (30% vs. 15%), with the assumption of a 5% non-inferiority margin. Based on a 10% dropout rate, a sample size of 160 pts is necessary to attain 80% power at nominal level of two-sided alpha of 0.05. We will test the superiority of abemaciclib plus ET as compared with paclitaxel if the non-inferiority is achieved. Both analyses, will be conducted with the Newcombe hybrid score method for confidence intervals. This trial was opened to accrual in May 2021.

Citation Format: Antonio Llombart-Cussac, Joseph Gligorov, Serena Di Cosimo, Cinta Albacar, Patricia Cortez, Eduardo Martinez-De Dueñas, Ana López, Vicente Carañana, Jacques Medioni, Luigi Cavanna, Marina Elena Cazzaniga, Sofia Braga, Passos Coelho, Miguel Sampayo-Cordero, Andrea Malfettone, José Manuel Pérez-García, Javier Cortes. Phase 2 study of abemaciclib in combination with endocrine therapy with or without paclitaxel induction in patients with hormone receptor-positive, HER2-negative advanced breast cancer and aggressive disease criteria: ABIGAIL [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 OT2-19-06.

Surrogate endpoints for early-stage breast cancer: a review of the state of the art, controversies, and future prospects

Drug approval for early-stage breast cancer (EBC) has been historically granted in the context of registration trials based on adequate outcomes such as disease-free survival and overall survival. Improvements in long-term outcomes have made it more difficult to demonstrate the clinical benefit of a new cancer drug in large, randomized, comparative clinical trials. Therefore, the use of surrogate endpoints rather than traditional measures allows for cancer drug trials to proceed with smaller sample sizes and shorter follow-up periods, which reduces drug development time. Among surrogate endpoints for breast cancer, the increase in pathological complete response (pCR) rates was considered appropriate for accelerated drug approval. The association between pCR and long-term outcomes was strongest in patients with aggressive tumor subtypes, such as triple-negative and human epidermal growth factor receptor 2 (HER2)-positive/hormone receptor-negative breast cancers. Whereas in hormone receptor-positive/HER2-negative EBC, the most accepted surrogate markers for endocrine therapy-based trials include changes in Ki67 and the preoperative endocrine prognostic index. Beyond the classic endpoints, further prognostic tools are required to provide EBC patients with individualized and effective therapies, and the neoadjuvant setting provides an excellent platform for drug development and biomarker discovery. Nowadays, the availability of multigene signatures is offering a standardized quantitative and reproducible tool to potentiate the efficacy of standard treatment for high-risk patients and develop de-escalated treatments for patients at lower risk of relapse. In this article, we first evaluate the surrogacies used for long-term outcomes and the underlying evidence supporting the use of each surrogate endpoint for the accelerated or regular drug approval process in EBC. Next, we provide an overview of the most recent studies and innovative strategies in a (neo)adjuvant setting as a platform to accelerate new drug approval. Finally, we highlight some clinical trials aimed at tailoring systemic treatment of EBC using prognosis-related factors or early biomarkers of drug sensitivity or resistance.

Fulvestrant-Palbociclib vs Letrozole-Palbociclib as Initial Therapy for Endocrine-Sensitive, Hormone Receptor-Positive, ERBB2-Negative Advanced Breast Cancer: A Randomized Clinical Trial

Importance

The cyclin-dependent kinase 4 and 6 inhibitor palbociclib in combination with letrozole has become a standard first-line treatment for patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer. Meanwhile, the antiestrogen fulvestrant was shown to be superior to anastrozole in the absence of cyclin-dependent kinase 4 and 6 inhibition for this patient population.

Objective

To assess whether fulvestrant is superior to letrozole when combined with palbociclib in the first-line scenario.

Design, Setting, and Participants

In this international, randomized, open-label, phase 2 clinical study conducted from July 30, 2015, to January 8, 2018, patients with hormone receptor-positive, ERBB2-negative advanced breast cancer with no prior therapy in the metastatic setting and endocrine-sensitive criteria were recruited from 47 centers in 7 countries. Data were analyzed from February 11 to May 15, 2020.

Interventions

Patients were randomly assigned (1:1 ratio) to receive palbociclib with either fulvestrant or letrozole. Stratification factors were type of disease presentation (de novo vs recurrent) and the presence of visceral involvement (yes vs no).

Main Outcomes and Measures

The primary end point was investigator-assessed progression-free survival determined by Response Evaluation Criteria in Solid Tumors, version 1.1.

Results

A total of 486 women (median age, 63 years [range, 25-90 years]; 3 Asian women [0.6%]; 4 Black women [0.8%]; 461 White women [94.9%]; 18 women of unknown race [3.7%]) were randomized (243 to fulvestrant-palbociclib and 243 to letrozole-palbociclib). Median investigator-assessed progression-free survival was 27.9 months (95% CI, 24.2-33.1 months) in the fulvestrant-palbociclib group vs 32.8 months (95% CI, 25.8-35.9 months) in the letrozole-palbociclib group (hazard ratio, 1.13; 95% CI, 0.89-1.45; P = .32). This result was consistent across the stratification factors. No significant differences were observed in objective response rate (46.5% vs 50.2%) and 3-year overall survival rate (79.4% vs 77.1%) for fulvestrant-palbociclib and letrozole-palbociclib, respectively. Grade 3-4 adverse events were comparable among treatment groups, and no new safety signals were identified. No treatment-related deaths were reported.

Conclusions and Relevance

Although fulvestrant-palbociclib demonstrated significant antitumor activity, this randomized clinical trial failed to identify an improvement in progression-free survival with this regimen over letrozole-palbociclib in patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT02491983.

Predictive Role of Leptin Receptor (Ob-R) Overexpression in Patients with Early Breast Cancer Receiving Neoadjuvant Systemic Treatment

The primary aim of this retrospective study was to investigate the correlation between the immunohistochemical expression of Ob-R (leptin receptor) with pCR (pathological complete response) in early breast cancer patients receiving neoadjuvant systemic treatment (NST). A total of 100 women with breast cancer receiving NST (2017-2020) followed by surgical resection were retrospectively obtained. Demographic parameters and clinicopathological factors (e.g., treatment modalities, immunohistochemistry (IHC), and cancer subtype) were obtained from the patient's clinical records. In the analyzed breast cancer cohort, high expression of Ob-R was found in 52% of tumors and there was a significantly higher incidence in the HER2+ and TNBC subgroups. Overall, a significantly greater percentage of patients with Ob-R positive tumors achieved pCR compared with Ob-R negative patients (57.7% vs. 27.1%; p = 0.002). This result was observed in most breast cancer subtypes. In patients with HER2+ breast cancer, there was no difference in Ob-R expression in relation to the HR status. Ob-R cell positivity was significantly higher in younger breast cancer patients (p = 0.008), those who were premenopausal (p = 0.011), and in those with a BMI > 25 kg/m² (p = 0.019). A significantly greater percentage of early breast cancer patients with Ob-R positive tumors achieved pCR compared with Ob-R negative patients. Furthermore, breast cancer patients with positive Ob-R expression were significantly younger than those with negative Ob-R expression. This association was not explained by differences in BMI between young and old patients.

The Impact of Excluding Nonrandomized Studies From Systematic Reviews in Rare Diseases: "The Example of Meta-Analyses Evaluating the Efficacy and Safety of Enzyme Replacement Therapy in Patients With Mucopolysaccharidosis"

Nonrandomized studies are usually excluded from systematic reviews. This could lead to loss of a considerable amount of information on rare diseases. In this article, we explore the impact of excluding nonrandomized studies on the generalizability of meta-analyses results on mucopolysaccharidosis (MPS) disease. A comprehensive search of systematic reviews on MPS patients up to May 2020 was carried out (CRD42020191217). The primary endpoint was the rate of patients excluded from systematic reviews if only randomized studies were considered. Secondary outcomes included the differences in patient and study characteristics between randomized and nonrandomized studies, the methods used to combine data from studies with different designs, and the number of patients excluded from systematic reviews if case reports were not considered. More than 50% of the patients analyzed have been recruited in nonrandomized studies. Patient characteristics, duration of follow-up, and the clinical outcomes evaluated differ between the randomized and nonrandomized studies. There are feasible strategies to combine the data from different randomized and nonrandomized designs. The analyses suggest the relevance of including case reports in the systematic reviews, since the smaller the number of patients in the reference population, the larger the selection bias associated to excluding case reports. Our results recommend including nonrandomized studies in the systematic reviews of MPS to increase the representativeness of the results and to avoid a selection bias. The recommendations obtained from this study should be considered when conducting systematic reviews on rare diseases.

Nobody dares stopping clinical research, not even COVID-19

In the global health emergency caused by the COVID-19, clinical trial management has proven to be critical for the pharmaceutical industry, sponsors, and healthcare professionals. Our experience as a sponsor managing interventional oncology clinical studies has provided us with some data and insights. Though limited by sample size, our data emphasize the importance of quickly adopting measures that first prioritize patient safety and data validity, then consider contingency measures such as telemedicine, virtual medical review, and remote monitoring. Successful adaptations of healthcare and patient management in response to COVID-19 have been fundamental to ensuring continuing clinical cancer research.

Pembrolizumab plus eribulin in hormone-receptor-positive, HER2-negative, locally recurrent or metastatic breast cancer (KELLY): An open-label, multicentre, single-arm, phase Ⅱ trial

BACKGROUND

Pembrolizumab has modest activity if used in patients with hormone-receptor-positive (HR+), HER2-negative, previously treated metastatic breast cancer (BC). Our study investigated whether there would be any clinical benefit in combining chemotherapy with pembrolizumab in a similar patient population.

METHODS

This single-arm, phase Ⅱ trial enrolled women aged ≥18 years with HR+, HER2-negative, inoperable, locally recurrent or metastatic BC. Patients were previously treated with hormonal therapy and 1-2 chemotherapy regimens for locally recurrent and/or metastatic BC. On each 21-day cycle, patients received intravenous pembrolizumab 200 mg on day 1 and eribulin 1∙23 mg/m² on days 1 and 8. The primary endpoint was the clinical benefit rate. Analysis of safety and activity was carried out in all patients who met the screening criteria and received at least 1 dose of study treatment. The trial is registered at ClinicalTrials.gov, NCT03222856.

RESULTS

Of the 44 patients enrolled between January 29 and October 17, 2018, clinical benefit was achieved in 25 (56∙8%, 95% confidence interval [CI]: 41∙0-71∙7), objective response in 18 (40∙9%, 95% CI: 26∙3-56∙8), median progression-free survival was 6∙0 months (95% CI: 3∙7-8∙4), and 1-year overall survival was 59∙1% (95% CI: 45∙8-76∙2). The most common treatment-emergent adverse events (AEs) of any grade were neutropenia (20 [45∙5%]), anaemia (17 [38∙6%]), alopecia (19 [43∙2%]), asthenia (19 [43∙2%]), diarrhoea (14 [31∙8%]), fatigue (14 [31∙8%]), and peripheral neuropathy (12 [27∙3%]). Serious AEs occurred in 14 (31∙8%) patients including febrile neutropenia (3 [6∙8%]), neutropenia (2 [4∙5%]), fever (2 [4∙5%]) and peripheral neuropathy (2 [4∙5%]). Immune-related AEs occurred in 11 (25∙0%) patients. One (2∙3%) patient died of cardiac arrest unrelated to study treatment.

CONCLUSION

Pembrolizumab plus eribulin demonstrates encouraging antitumour activity in patients with heavily pre-treated, HR+, HER2-negative, locally recurrent or metastatic BC. The safety and tolerability of the combination is similar to eribulin or pembrolizumab monotherapy.

Abstract PS10-17: Palbociclib (P) in combination with fulvestrant (F) or letrozole (L) in endocrine-sensitive patients (pts) with hormone receptor (HR)[+]/HER2[-] metastatic breast cancer (MBC): detailed safety analysis from a multicenter, randomized, open-label, phase II trial (PARSIFAL)

Background: P led to a meaningful improvement in clinical outcomes when used in combination with endocrine therapy for first- or later-line regimen in HR[+]/HER2[-] MBC. Grade 3-4 neutropenia was the most common adverse event (AE) in the P-containing regimens. Although venous thromboembolic events (VTE) have been rarely reported in registrational trials, a systematic review and meta-analysis of randomized controlled trials demonstrated a higher rate of these AEs. Moreover, rare but severe cases of interstitial lung disease (ILD)/pneumonitis have been observed during post-approval use of P. Here, we present a comprehensive toxicity profile of pts included in the PARSIFAL study, with particular emphasis given to AEs of special interest of the overall safety population. Methods: A total of 486 pts with HR[+]/HER2[-] MBC with no prior therapy in the advanced setting and endocrine sensitive criteria (relapse &gt;12 months [mo] after the end of adjuvant endocrine therapy or diagnosed with de novo metastatic disease) were randomly assigned 1:1 to receive P (oral 125 mg/day [d]; 3 weeks on/1 week off) plus either F (intramuscular injection 500 mg/d; d 0, 14, 28, and then every 28 ds) or L (oral 2.5 mg/d). Pts were stratified by visceral involvement and type of disease presentation (de novo/recurrent). Safety assessments included blood analysis and collection of vital signs at screening, d1 of each cycle, and end of treatment/withdrawal. Severity was graded as per the NCI Common Terminology Criteria for Adverse Events v.4.03. Results: The incidence rate of any grade, grade 3-4, and serious AEs was 99.6%, 80.9%, and 29.9%, respectively, in the FP arm, and 99.2%, 78.5%, and 21.1% in the LP arm. Discontinuations due to AEs were 5.4% in the FP arm and 2.1% in the LP arm. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both arms. Febrile neutropenia was reported in 1.2% (3 pts) and 0.4% (1 patient) in the FP and LP arms, respectively. The rate of VTE of any grade was 5.8% (14 pts) in the FP arm and 4.5% (11 pts) in the LP arm (p = 0.531). Among 18 pts who had grade ≥ 3 pulmonary embolism (PE), the incidence reported in the FP and LP arms was 5% (12 pts) vs 2.5% (6 pts), respectively, and many of them (n=16, 88.9%) were unrelated PE. Asymptomatic grade 3 PE was reported in 10 pts of the entire study population on every 3-mo CT scan. Further, in 5 pts PE was detected in the context of progressive disease. Median time from the first dose of study drugs to occurrence of PE was 4.1 mo (range 1.4-32.0 mo) in the FP arm and 7 mo (range 1.8-19.3 mo) in the LP arm. Analysis of baseline characteristics in the whole population revealed that older pts had a significantly increased risk for developing PE (69.5 years [range 47-84 years]; p &lt; 0.01). ECOG performance status, menopausal status, metastatic disease, visceral involvement, number of disease sites, and prior therapies including antithrombotic agents did not significantly increase the risk for developing PE. Grade 3 ILD/pneumonitis was rarely observed in the FP and LP arms (0.8% vs 1.2%, respectively) with no grade 4 AE. Conclusions: First-line treatment with FP and LP for HR[+]/HER2[-] MBC in the PARSIFAL study confirmed the favorable safety profile, with neutropenia representing the most common AE. Although rare, ILD/pneumonitis can be a side effect of P-based regimens. VTE and PE incidence rates were low and consistent with age-specific analyses from PALOMA trials and breast cancer population. Early detection of these AEs may assist in optimizing their management.

Citation Format: José Manuel Pérez-García, Antonio Llombart-Cussac, Meritxell Bellet, Florence Dalenc, Miguel J. Gil Gil, Manuel Ruiz Borrego, Joaquín Gavilá, Miguel Sampayo-Cordero, Elena Aguirre, Peter Schmid, Frederik Marmé, Serena Di Cosimo, Joseph Gligorov, Andreas Schneeweiss, Joan Albanell, Pilar Zamora, Duncan Wheatley, Eduardo Martínez-De Dueñas, Vicente Carañana, Kepa Amillano, Andrea Malfettone, Javier Cortés. Palbociclib (P) in combination with fulvestrant (F) or letrozole (L) in endocrine-sensitive patients (pts) with hormone receptor (HR)[+]/HER2[-] metastatic breast cancer (MBC): detailed safety analysis from a multicenter, randomized, open-label, phase II trial (PARSIFAL) [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 PS10-17.

Inclusion of non-inferiority analysis in superiority-based clinical trials with single-arm, two-stage Simon's design

INTRODUCTION

Non-inferiority (NI) analysis is not usually considered in the early phases of clinical development. In some negative phase II trials, a post-hoc NI analysis justified additional phase III trials that were successful. However, the risk of false positive achievements was not controlled in these early phase analyses. We propose to preplan NI analyses in superiority-based Simon's two-stage designs to control type I and II error rates.

METHODS

Simulations have been proposed to assess the control of type I and II errors rates with this method. A total of 12,768 two-stage Simon's design trials were constructed based on different assumptions of rejection response probability, desired response probability, type I and II errors, and NI margins. P-value and type II error were calculated with stochastic ordering using Uniformly Minimum Variance Unbiased Estimator. Type I and II errors were simulated using the Monte Carlo method. The agreement between calculated and simulated values was analyzed with Bland-Altman plots.

RESULTS

We observed the same level of agreement between calculated and simulated type I and II errors from both two-stage Simon's superiority designs and designs in which NI analysis was allowed. Different examples has been proposed to explain the utility of this method.

CONCLUSION

Inclusion of NI analysis in superiority-based single-arm clinical trials may be useful for weighing additional factors such as safety, pharmacokinetics, pharmacodynamic, and biomarker data while assessing early efficacy. Implementation of this strategy can be achieved through simple adaptations to existing designs for one-arm phase II clinical trials.

Trastuzumab Emtansine Plus Non-Pegylated Liposomal Doxorubicin in HER2-Positive Metastatic Breast Cancer (Thelma): A Single-Arm, Multicenter, Phase Ib Trial

Simple Summary

Considering the favorable overall safety profile of trastuzumab emtansine (T-DM1), the low expected rate of cardiotoxicity, and the synergistic effect of anthracyclines with Human Epidermal Growth Factor Receptor 2 (HER2)-targeting agents, it is hypothesized that T-DM1 may be safely combined with non-pegylated liposomal doxorubicin (NPLD). In the THELMA trial, the effect of adding NPLD to T-DM1 was evaluated with the aim of enhancing T-DM1 efficacy using an extensive cardiological assessment in trastuzumab- and taxane-pretreated patients with HER2-positive metastatic breast cancer. Despite an unlikely drug synergism, this combination was generally well tolerated without clinically relevant worsening of cardiac function. No relationship was identified between early predictors of heart failure and left ventricular ejection fraction changes. Thus, the combination of T-DM1 plus NPLD is safe, but this regimen does not seem to improve T-DM1 antitumor activity in this setting.

Abstract

The paper assesses the dose-limiting toxicities and the maximum tolerated dose (MTD) of trastuzumab emtansine (T-DM1) combined with non-pegylated liposomal doxorubicin (NPLD) in HER2-positive (HER2+) metastatic breast cancer (MBC). This single-arm, open-label, phase Ib trial (NCT02562378) enrolled anthracycline-naïve HER2+ MBC patients who had progressed on trastuzumab and taxanes. Patients received a maximum of 6 cycles of NPLD intravenously (IV) at various dose levels (45, 50, and 60 mg/m²) in the “3 plus 3” dose-escalation part. During expansion, they received 60 mg/m² of NPLD every 3 weeks (Q3W) plus standard doses of T-DM1. The MTD was T-DM1 3.6 mg/kg plus NPLD 60 mg/m² administered IV Q3W. No clinically relevant worsening of cardiac function was observed. Among all evaluable patients, the overall response rate was 40.0% (95%CI, 16.3–67.7) with a median duration of response of 6.9 months (95%CI, 4.8–9.1). Clinical benefit rate was 66.7% (95%CI, 38.4–88.2) and median progression-free survival was 7.2 months (95%CI, 4.5–9.6). No significant influence of NPLD on T-DM1 pharmacokinetics was observed. The addition of NPLD to T-DM1 is feasible but does not seem to improve the antitumor efficacy of T-DM1 in HER2+ MBC patients.

The Value of Case Reports in Systematic Reviews from Rare Diseases. The Example of Enzyme Replacement Therapy (ERT) in Patients with Mucopolysaccharidosis Type II (MPS-II)

BACKGROUND

Case reports are usually excluded from systematic reviews. Patients with rare diseases are more dependent on novel individualized strategies than patients with common diseases. We reviewed and summarized the novelties reported by case reports in mucopolysaccharidosis type II (MPS-II) patients treated with enzyme replacement therapy (ERT).

METHODS

We selected the case reports included in a previous meta-analysis of patients with MPS-II treated with ERT. Later clinical studies evaluating the same topic of those case reports were reported. Our primary aim was to summarize novelties reported in previous case reports. Secondary objectives analyzed the number of novelties evaluated in subsequent clinical studies and the time elapsed between the publication of the case report to the publication of the clinical study.

RESULTS

We identified 11 innovative proposals in case reports that had not been previously considered in clinical studies. Only two (18.2%) were analyzed in subsequent nonrandomized cohort studies. The other nine novelties (81.8%) were analyzed in later case reports (five) or were not included in ulterior studies (four) after more than five years from their first publication.

CONCLUSIONS

Case reports should be included in systematic reviews of rare disease to obtain a comprehensive summary of the state of research and offer valuable information for healthcare practitioners.

PARSIFAL: A randomized, multicenter, open-label, phase II trial to evaluate palbociclib in combination with fulvestrant or letrozole in endocrine-sensitive patients with estrogen receptor (ER)[+]/HER2[-] metastatic breast cancer

1007

Background: The CDK4/6 inhibitor palbociclib (P) in combination with letrozole (L) has become a standard first-line treatment for patients (pts) with luminal metastatic breast cancer (MBC) (PALOMA-1 & 2 trials). Meanwhile, the anti-estrogen fulvestrant (F) showed to be superior to anastrozole in the same population (FALCON trial). We aimed to identify the best endocrine agent to combine with P in this first-line scenario. Methods: A total of 486 pts with ER[+]/HER2[-] MBC with no prior therapy in the advanced setting and endocrine sensitive criteria (relapse > 12 months [mo] after the end of adjuvant endocrine therapy or diagnosed with “de novo” metastatic disease) were randomly assigned (1:1 ratio) to receive P (oral 125 mg/day [d]; 3 wks on/1 wk off) plus F 500 mg/d (I.M Days 0, 14, 28, and then every 28 d) or PL (oral 2.5 mg/d). Pts were stratified by visceral involvement and type of disease presentation (“de novo”/recurrent). Primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS), overall response rate (ORR), clinical benefit rate (CBR), and safety. 254 events were needed with 80% power to detect a hazard ratio (HR) ≤0.7 in favor of PF (2-sided α = 0.05). Results: By March 9th, 2020, 256 PFS events occurred. Pts characteristics were well balanced. Median age was 62 years (range: 25–90), 56.6% were ECOG 0, 40.7% had “de novo” metastatic disease, 48% had visceral disease, and 43.6% with ≥3 organ sites involved. At median follow-up of 32 mo, median PFS was 27.9 mo (95% confidence interval [CI], 24.2-33.1) with PF and 32.8 mo (95% CI, 25.8-35.9) with PL (HR: 1.1; 95% CI, 0.9-1.5; P = 0.321). No differences were observed for pts with or without visceral involvement (HR: 1.3 and HR: 0.97 respectively, interaction P = 0.275), and for “de novo” or recurrent metastatic disease (HR: 1.1 and HR: 1.1 respectively, P = 0.979). The 4-year OS rate was 67.6% in PF and 67.5% in PL arm (HR: 1; 95% CI, 0.7-1.5; P = 0.986). No differences were observed in ORR or CBR between arms. Grade ≥3 adverse events were similar in both arms, being neutropenia and leukopenia the most frequent. No treatment-related deaths were reported. Conclusion: This study was not able to identify an improvement in PFS for PF over PL in patients with endocrine-sensitive ER[+]/HER2[-] MBC. As both arms demonstrated comparable 4 years-OS, PF is a reasonable alternative to PL in this setting. Clinical trial information: NCT02491983 .

Chemotherapy (CT) de-escalation using an FDG-PET/CT (F-PET) and pathological response-adapted strategy in HER2[+] early breast cancer (EBC): PHERGain Trial

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Background: Dual trastuzumab plus pertuzumab (HP) has shown promising pathologic complete response (pCR) rates in HER2[+] EBC although lower to CT regimens. Identification of new markers of sensitivity to HP could help to de-escalate CT. PHERGain assessed early metabolic response by F-PET to neoadjuvant HP and the opportunity of CT de-escalation with a response-adapted strategy in patients (pts) with HER2[+] EBC. Methods: PHERGain randomized (1:4 ratio) centrally-confirmed HER2[+] stage I-III EBC pts to receive either docetaxel (T), carboplatin (C), and HP (cohort A) or HP ± endocrine therapy (ET) (cohort B). Randomization was stratified by hormone receptor (HR) status. Pts with subclinical metastases by F-PET were included in a different cohort (cohort C). Centrally-reviewed F-PET was performed prior to randomization and after 2 cycles of TX (cohorts A/B). Cohort A pts completed a total of 6 cycles regardless of F-PET results. Cohort B/PET-responder (RX) pts continued with HP ± ET for 6 cycles, while PET-non-RX pts were switched to receive 6 cycles of TCHP. After surgery, cohort B/PET-RX pts who did not achieve a pCR received 6 cycles of TCHP and all pts from cohorts A/B completed 18 cycles of HP. Cohort C pts received 6 cycles of TCHP. Co-primary endpoints were breast/axilla pCR rate (ypT0/isN0) among cohort B/PET-RX pts and 3-year invasive disease-free survival (iDFS) in pts allocated to cohort B. Results: A total of 376 pts were included (71 pts in cohort A, 285 pts in cohort B, and 20 pts in cohort C). In cohort B, median age was 50 years, 49.2% had node-positive disease, and 67.4% had HR+ tumors. pCR in cohort A was achieved in 41 pts (57.7%, 95% CI 47.4-69.4%) and it was observed in 101 pts included in cohort B (35.4%, 95% CI 29.9-41.3%). Among cohort B pts, 227 (79.6%) were PET-RX; 86 of them (37.9%, 95% CI 31.6-44.5%) obtained a pCR. Among PET-non-RX pts, 15 (25.9%, 95% CI 15.3-39%) achieved a pCR after adding CT (TCHP). PET-RX pCR by HR status was 44.3% for HR[-] and 35% for HR[+] (p = 0.184). The incidence of commonly reported adverse events (AEs) was higher in pts allocated to cohort A (grade≥3 AEs 58.8 vs 12%; serious AEs 29.4 vs 4.6%). The rate of pts with a ≥10% global health status decline in cohorts A and B were 40.8 and 23.5%, respectively. Conclusions: F-PET identify pts with HER2[+] EBC who are more likely to benefit from CT-free dual HER2-blockade with HP. Follow-up is ongoing for iDFS endpoint. Depending on the results of this second co-primary endpoint, this strategy could select a group of HER2[+] EBC pts who would not need CT. Clinical trial information: NCT03161353 .

Agreement between results of meta-analyses from case reports and clinical studies, regarding efficacy and safety of idursulfase therapy in patients with mucopolysaccharidosis type II (MPS-II). A new tool for evidence-based medicine in rare diseases

Background

A preliminary exploratory study shows solid agreement between the results of case reports and clinical study meta-analyses in mucopolysaccharidosis Type I (MPS-I) adult patients. The aim of the present study is to confirm previous results in another patient population, suffering from mucopolysaccharidosis Type II (MPS-II).

Methods

A systematic review and meta-analysis of case reports published by April 2018 was conducted for MPS-II patients treated with enzyme replacement therapy (ERT). The study is reported in accordance with PRISMA and MOOSE guidelines (PROSPERO database code CRD42018093408). The assessed population and outcomes were the same as previously analyzed in a meta-analysis of MPS-II clinical studies. The primary endpoint was the percent of clinical cases showing improvement in efficacy outcome, or no harm in safety outcome after ERT initiation. A restrictive procedure to aggregate case reports, by selecting standardized and well-defined outcomes, was proposed. Different sensitivity analyses were able to evaluate the robustness of results.

Results

Every outcome classified as “acceptable evidence group” in our case report meta-analysis had been graded as “moderate strength of evidence” in the aforementioned meta-analysis of clinical studies. Sensitivity, specificity, and positive-negative predictive values for results of both meta-analyses reached 100%, and were deemed equivalent.

Conclusions

Aggregating case reports quantitatively, rather than analyzing them qualitatively, may improve conclusions in rare diseases and personalized medicine. Additionally, we propose some methods to evaluate publication bias and heterogeneity of the included studies in a meta-analysis of case reports.

Agreement between the results of meta-analyses from case reports and from clinical studies regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I who initiated enzyme replacement therapy in adult age: An example of case reports meta-analyses as an useful tool for evidence-based medicine in rare diseases

BACKGROUND

Case reports might have a prominent role in the rare diseases field, due to the small number of patients affected by one such disease. A previous systematic review regarding the efficacy of laronidase therapy in patients with mucopolysaccharidosis type I (MPS-I) who initiated enzyme replacement therapy (ERT) in adult age has been published. The review included a meta-analysis of 19 clinical studies and the description of eleven case reports. It was of interest to perform a meta-analysis of those case reports to explore the role of such meta-analyses as a tool for evidence-based medicine in rare diseases.

METHODS

The study included all case reports with standard treatment regimen. Primary analysis was the percentage of case reports showing an improvement in a specific outcome. Only when that percentage was statistically higher than 5%, the improvement was confirmed as such. The outcomes that accomplished this criterion were ranked and compared to the GRADE criteria obtained by those same outcomes in the previous meta-analysis of clinical studies.

RESULTS

There were three outcomes that had a significant improvement: Urine glycosaminoglycans, liver volume and 6-minute walking test. Positive and negative predictive values, sensitivity and specificity for the results of the meta-analysis of case reports as compared to that of clinical studies were 100%, 88.9%, 75% and 100%, respectively. Accordingly, absolute (Rho=0.82, 95%CI: 0.47 to 0.95) and relative agreement (Kappa=0.79, 95%CI: 0.593 to 0.99) between the number of case reports with improvement in a specific outcome and the GRADE evidence score for that outcome were good. Sensitivity analysis showed that agreement between the meta-analysis of case reports and that of the clinical studies were good only when using a strong confirmatory strategy for outcome improvement in case reports.

CONCLUSIONS

We found an agreement between the results of meta-analyses from case reports and from clinical studies in the efficacy of laronidase therapy in patients with MPS-I who initiated ERT in adult age. This agreement suggests that combining case reports quantitatively, rather than analyzing them separately or qualitatively, may improve conclusions in the field of rare diseases.