Breast Cancer Index and Prediction of Extended Aromatase Inhibitor Therapy Benefit in Hormone Receptor-positive Breast Cancer from the NRG Oncology/NSABP B-42 Trial

PURPOSE

BCI (H/I) has been shown to predict extended endocrine therapy (EET) benefit. We examined BCI (H/I) for EET benefit prediction in NSABP B-42, which evaluated extended letrozole therapy (ELT) in hormone receptor-positive breast cancer patients after 5 years of ET.

METHODS

Stratified Cox model was used to analyze RFI as primary endpoint, with DR, BCFI, and DFS, as secondary endpoints. Due to a non-proportional effect of ELT on DR, time-dependent analyses were performed.

RESULTS

The translational cohort included 2,178 patients (45% BCI (H/I)-High, 55% BCI (H/I)-Low). ELT showed an absolute 10-year RFI benefit of 1.6% (P=0.10), resulting in an underpowered primary analysis (50% power). ELT benefit and BCI (H/I) did not show a significant interaction for RFI (BCI [(H/I])-Low: 10y absolute benefit 1.1% [HR=0.70, 0.43-1.12, P=0.13]; BCI [(H/I])-High: 2.4% [HR=0.83, 0.55-1.26, p=0.38]; Pinteraction=0.56). Time-dependent DR analysis showed that after 4y, BCI (H/I)-High patients had significant ELT benefit (HR=0.29, 0.12-0.69, P<0.01), whereas BCI (H/I)-Low patients were less likely to benefit (HR=0.68, 0.33-1.39, P=0.29) (Pinteraction=0.14). Prediction of ELT benefit by BCI (H/I) was more apparent in the HER2- subset after 4y (ELT-by-BCI (H/I) Pinteraction=0.04).

CONCLUSIONS

BCI(H/I)-High vs -Low did not show a statistically significant difference in ELT benefit for the primary endpoint (RFI). However, in time-dependent DR analysis, BCI (H/I)-High patients experienced statistically significant benefit from ELT after 4y, whereas (H/I)-Low patients did not. Because BCI (H/I) has been validated as a predictive marker of EET benefit in other trials, additional follow-up may enable further characterization of BCI's predictive ability.

Ten-year update: NRG Oncology/National Surgical Adjuvant Breast and Bowel Project B-42 randomized trial: extended letrozole therapy in early-stage breast cancer

BACKGROUND

The National Surgical Adjuvant Breast and Bowel Project B-42 trial evaluated extended letrozole therapy (ELT) in postmenopausal breast cancer patients who were disease free after 5 years of aromatase inhibitor (AI)-based therapy. Seven-year results demonstrated a nonstatistically significant trend in disease-free survival (DFS) in favor of ELT. We present 10-year outcome results.

METHODS

In this double-blind, phase III trial, patients with stage I-IIIA hormone receptor-positive breast cancer, disease free after 5 years of an AI or tamoxifen followed by an AI, were randomly assigned to 5 years of letrozole or placebo. Primary endpoint was DFS, defined as time from random assignment to breast cancer recurrence, second primary malignancy, or death. All statistical tests are 2-sided.

RESULTS

Between September 2006 and January 2010, 3966 patients were randomly assigned (letrozole: 1983; placebo: 1983). Median follow-up time for 3923 patients included in efficacy analyses was 10.3 years. There was statistically significant improvement in DFS in favor of letrozole compared with placebo (hazard ratio [HR] = 0.85, 95% confidence interval [CI] = 0.74 to 0.96; P  = .01; 10-year DFS: placebo = 72.6%, letrozole = 75.9%, absolute difference = 3.3%). There was no difference in the effect of letrozole on overall survival (HR = 0.97, 95% CI = 0.82 to 1.15; P  = .74). Letrozole statistically significantly reduced breast cancer-free interval events (HR = 0.75, 95% CI = 0.62 to 0.91; P = .003; absolute difference in cumulative incidence = 2.7%) and distant recurrences (HR = 0.72, 95% CI = 0.55 to 0.92; P = .01; absolute difference = 1.8%). The rates of osteoporotic fractures and arterial thrombotic events did not differ between treatment groups.

CONCLUSIONS

The beneficial effect of ELT on DFS persisted at 10 years. Letrozole also improved breast cancer-free interval and distant recurrences without improving overall survival. Careful assessment of potential risks and benefits is necessary for selecting appropriate candidates for ELT.

Randomized Phase II Trial Comparing Bevacizumab Plus Carboplatin and Paclitaxel With Carboplatin and Paclitaxel Alone in Previously Untreated Locally Advanced or Metastatic Non-Small-Cell Lung Cancer

PURPOSE

To investigate the efficacy and safety of bevacizumab plus carboplatin and paclitaxel in patients with advanced or recurrent non-small-cell lung cancer.

PATIENTS AND METHODS

In a phase II trial, 99 patients were randomly assigned to bevacizumab 7.5 (n = 32) or 15 mg/kg (n = 35) plus carboplatin (area under the curve = 6) and paclitaxel (200 mg/m²) every 3 weeks or carboplatin and paclitaxel alone (n = 32). Primary efficacy end points were time to disease progression and best confirmed response rate. On disease progression, patients in the control arm had the option to receive single-agent bevacizumab 15 mg/kg every 3 weeks.

RESULTS

Compared with the control arm, treatment with carboplatin and paclitaxel plus bevacizumab (15 mg/kg) resulted in a higher response rate (31.5% v 18.8%), longer median time to progression (7.4 v 4.2 months) and a modest increase in survival (17.7 v 14.9 months). Of the 19 control patients that crossed over to single-agent bevacizumab, five experienced stable disease, and 1-year survival was 47%. Bleeding was the most prominent adverse event and was manifested in two distinct clinical patterns; minor mucocutaneous hemorrhage and major hemoptysis. Major hemoptysis was associated with squamous cell histology, tumor necrosis and cavitation, and disease location close to major blood vessels.

CONCLUSION

Bevacizumab in combination with carboplatin and paclitaxel improved overall response and time to progression in patients with advanced or recurrent non-small-cell lung cancer. Patients with nonsquamous cell histology appear to be a subpopulation with improved outcome and acceptable safety risks.

Efficacy and Safety of Trastuzumab as a Single Agent in First-Line Treatment of HER2-Overexpressing Metastatic Breast Cancer

PURPOSE

To evaluate the efficacy and safety of first-line, single-agent trastuzumab in women with HER2-overexpressing metastatic breast cancer.

PATIENTS AND METHODS

One hundred fourteen women with HER2-overexpressing metastatic breast cancer were randomized to receive first-line treatment with trastuzumab 4 mg/kg loading dose, followed by 2 mg/kg weekly, or a higher 8 mg/kg loading dose, followed by 4 mg/kg weekly.

RESULTS

The objective response rate was 26% (95% confidence interval [CI], 18.2% to 34.4%), with seven complete and 23 partial responses. Response rates in 111 assessable patients with 3+ and 2+ HER2 overexpression by immunohistochemistry (IHC) were 35% (95% CI, 24.4% to 44.7%) and none (95% CI, 0% to 15.5%), respectively. The clinical benefit rates in assessable patients with 3+ and 2+ HER2 overexpression were 48% and 7%, respectively. The response rates in 108 assessable patients with and without HER2 gene amplification by fluorescence in situ hybridization (FISH) analysis were 34% (95% CI, 23.9% to 45.7%) and 7% (95% CI, 0.8% to 22.8%), respectively. Seventeen (57%) of 30 patients with an objective response and 22 (51%) of 43 patients with clinical benefit had not experienced disease progression at follow-up at 12 months or later. The most common treatment-related adverse events were chills (25% of patients), asthenia (23%), fever (22%), pain (18%), and nausea (14%). Cardiac dysfunction occurred in two patients (2%); both had histories of cardiac disease and did not require additional intervention after discontinuation of trastuzumab. There was no clear evidence of a dose-response relationship for response, survival, or adverse events.

CONCLUSION

Single-agent trastuzumab is active and well tolerated as first-line treatment of women with metastatic breast cancer with HER2 3+ overexpression by IHC or gene amplification by FISH.

Multinational Study of the Efficacy and Safety of Humanized Anti-HER2 Monoclonal Antibody in Women Who Have HER2-Overexpressing Metastatic Breast Cancer That Has Progressed After Chemotherapy for Metastatic Disease

PURPOSE

Overexpression of the HER2 protein occurs in 25% to 30% of human breast cancers and leads to a particularly aggressive form of the disease. Efficacy and safety of recombinant humanized anti-HER2 monoclonal antibody as a single agent was evaluated in women with HER2-overexpressing metastatic breast cancer that had progressed after chemotherapy for metastatic disease.

PATIENTS AND METHODS

Two hundred twenty-two women, with HER2-overexpressing metastatic breast cancer that had progressed after one or two chemotherapy regimens, were enrolled. Patients received a loading dose of 4 mg/kg intravenously, followed by a 2-mg/kg maintenance dose at weekly intervals.

RESULTS

Study patients had advanced metastatic disease and had received extensive prior therapy. A blinded, independent response evaluation committee identified eight complete and 26 partial responses, for an objective response rate of 15% in the intent-to-treat population (95% confidence interval, 11% to 21%). The median duration of response was 9.1 months; the median duration of survival was 13 months. The most common adverse events, which occurred in approximately 40% of patients, were infusion-associated fever and/or chills that usually occurred only during the first infusion, and were of mild to moderate severity. These symptoms were treated successfully with acetaminophen and/or diphenhydramine. The most clinically significant adverse event was cardiac dysfunction, which occurred in 4.7% of patients. Only 1% of patients discontinued the study because of treatment-related adverse events.

CONCLUSION

Recombinant humanized anti-HER2 monoclonal antibody, administered as a single agent, produces durable objective responses and is well tolerated by women with HER2-overexpressing metastatic breast cancer that has progressed after chemotherapy for metastatic disease. Side effects that are commonly observed with chemotherapy, such as alopecia, mucositis, and neutropenia, are rarely seen.

Abstract P5-13-08: Identification of PD-L1+ status as a candidate predictive biomarker of response to talazoparib (TALA) in the phase 3 EMBRACA study

Background: Loss-of-function mutations in genes encoding components of the homologous recombination DNA damage response (DDR) machinery, notably BRCA1/2, are associated with tumor sensitivity to poly(ADP-ribose) polymerase inhibitors (PARPi). In EMBRACA, the PARPi TALA improved progression-free survival (PFS) (HR [95% CI] 0.54 [0.41-0.71], P&lt;0.001) vs chemotherapy (CT) in germline BRCA-mutated (gBRCAm) HER2− advanced breast cancer. BRCA1/2 deficiency is associated with elevated PD-L1 expression in ovarian cancers, and PARP inhibition has been associated with PD-L1 upregulation in nonclinical models (Stewart et al, Cancer Res 2018;78:6717-25). Little is known about the potential for PD-L1 expression to modulate sensitivity to PARPi monotherapy in the clinic. Recently, a neoadjuvant study of olaparib in unselected, primary triple-negative breast cancer (TNBC), demonstrated a significant correlation between PD-L1 expression (using the 22C3 antibody) and response to olaparib (Eikesdal et al, Ann Oncol 2021;32:240-9). In contrast, this EMBRACA analysis assessed the contribution of PD-L1 status to TALA sensitivity in a uniformly gBRCAm patient (pt) population. Methods: Available baseline tumor tissue blocks from 120 of 431 EMBRACA pts (28% of intent-to-treat) were sectioned and slides immunostained using SP142/Ventana anti-PD-L1 at HistoGeneX (Naperville, Illinois). PD-L1 immunohistochemistry (IHC) status was assessed as the proportion of tumor area occupied by PD-L1 stained immune cells (IC) of any intensity, with ≥1% defined as PD-L1+. The overall response rate (ORR), defined as unconfirmed complete or partial response (CR/PR), was assessed by investigators. PFS was assessed by an Independent Review Facility. Results: 92/120 (77%) tumors were evaluable for PD-L1 IHC status. Of these 92 evaluable tumors, 9/36 (25%) TNBC and 15/56 (27%) hormone receptor-positive (HR+) tumors were PD-L1+ (24/92, 26% combined TNBC and HR+). In the TALA arm, the ORR was similar for PD-L1+ and PD-L1− tumors for TNBC pts: 2/5 (40%) and 6/19 (32%), respectively. In contrast, the ORR was higher for PD-L1+ vs PD-L1− tumors for HR+ pts: 11/12 (92%) vs 12/31 (39%), exact P value=0.002 (for combined TNBC and HR+, 13/17 [76%] vs 18/50 [36%], P=0.005). For the CT arm, the limited numbers evaluable for both PD-L1 and response (n=25 total), with only one response, precluded similar analysis. Based on the imbalanced results in ORR according to PD-L1 status in pts with HR+ disease, Cox regression analysis was used to explore potential associations of PD-L1 status with PFS. In the TALA arm, median PFS was similar for TNBC independent of PD-L1 status (6.3 mo and 7.0 mo, respectively; HR [95% CI] 1.207 [0.371-3.929]). Median PFS was numerically longer for PD-L1+ vs PD-L1− for HR+ tumors; this difference was not significant (20.2 mo vs 9.2 mo; HR [95% CI] 1.154 [0.395-3.367]). In the CT arm, PD-L1 status was not associated with PFS, although the PD-L1 subgroups were small (For HR+: PD-L1+, n=3; PD-L1−, n=10). Conclusions: Based on these exploratory, retrospective subgroup analyses, PD-L1 positivity by SP142/Ventana was lower in EMBRACA than previously reported in TNBC using the same scoring algorithm: 24/92 (26%) vs 369/902 (41%) in IMpassion130 (Schmid et al, Lancet Oncol 2020;21:44-59). PD-L1+ status was associated with higher ORR in HR+ EMBRACA pts receiving TALA. Interestingly, the enhanced responsiveness for PD-L1+ was not associated with improved PFS, although this assessment is complicated by low pt numbers. Further research is warranted to explore the relationship between baseline tumor PD-L1 status and sensitivity to PARPi, particularly in light of ongoing clinical studies evaluating combinations of immunotherapy and PARPi.

Citation Format: Hope S. Rugo, Joanne L. Blum, A. Douglas Laird, Sara A. Hurvitz, Johannes Ettl, Lida A. Mina, Kyung-Hun Lee, Anthony Gonçalves, Rinat Yerushalmi, Young-Hyuck Im, Miguel Martin, Louis Fehrenbacher, Henri H. Roché, Ying Chen, Silvana Lanzalone, Jijumon Chelliserry, Wolfgang Eiermann, Jennifer K. Litton. Identification of PD-L1+ status as a candidate predictive biomarker of response to talazoparib (TALA) in the phase 3 EMBRACA 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 P5-13-08.

Abstract PD15-05: Assessment of estrogen receptor (ESR1) mRNA expression for prediction of extended aromatase inhibitor benefit in HR-positive breast cancer using NRG Oncology/NSABP B-42

Background: In NSABP B-14, the quantitative levels of ESR1 mRNA, assessed using the standardized 21-gene assay and qRT-PCR platform predicted tamoxifen benefit (interaction p-value &lt;0.001). NSABP B-42 evaluated the effect of extended letrozole in postmenopausal women with hormone receptor-positive breast cancer who have completed 5 years of hormonal therapy with either an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor. We proposed to determine if ESR1 mRNA, reported as the quantitative ER single gene score, is predictive of the magnitude of benefit from extended adjuvant endocrine therapy with letrozole in patients enrolled in NSABP B-42. Methods: This prospectively planned retrospective study used a stratified cohort sample drawn from the 2,589 B-42 patients with available tumor tissue blocks and appropriate consent. All 133 patients who experienced distant recurrence and 48 patients who experienced local/regional but not distant recurrence were included along with a stratified random sample of 547/2,408 patients without recurrence. The primary endpoint was distant recurrence. The primary analysis tested for the interaction between the continuous ER single gene score and the effect of extended letrozole treatment using a weighted Cox proportional hazards regression model. A secondary analysis considered the ER single gene score categorized using the prespecified cutoff of ≤9.1 versus &gt;9.1. Recurrence-free interval was a secondary endpoint. Results: The results of the assay were available for 587 patients. The median ER score was 10.2 (IQR 9.3-11.0). There were 131 patients (23.2% weighted) with ER ≤9.1 and 456 (76.8% weighted) with ER &gt;9.1. No significant interaction of the effect of extended letrozole treatment was found for either the ER single gene score (interaction hazard ratio letrozole vs. placebo with an IQR change in ER score 1.10, 95% CI 0.66 - 1.82, p=.72) or the categories ER ≤9.1 (treatment HR=0.40, 95% CI 0.15-1.06) or ER &gt;9.1 (treatment HR=0.70, 95% CI 0.43-1.12) (interaction p=.32). There was also no apparent prognostic effect of the ER single gene score for distant recurrence with placebo treatment after 5 years of endocrine therapy (p=.12). Results were similar in analyses of any recurrence, analyses adjusting for the proliferation axis from the 21-gene assay, and subgroup analyses by nodal and HER2-status. Conclusions: The B-42 study provided no evidence that ESR1 mRNA as measured by the ER single gene score can inform decisions regarding extended letrozole therapy after 5 years of adjuvant endocrine therapy. Confidence intervals were relatively wide but rule out a strong predictive effect of the ER single gene score in the expected direction. Support: U10CA180868, -180822, U24CA196067; Novartis; Exact Sciences

Citation Format: Eleftherios Mamounas, Hanna Bandos, Priya Rastogi, Michael R Crager, Carolyn Mies, Peter C Lucas, Charles E Geyer, Jr, Louis Fehrenbacher, Mark L Graham, Stephen KL Chia, Adam M Brufsky, Janice M Walshe, Gamini S Soori, Shaker R Dakhil, Soonmyung Paik, Sandra M Swain, Frederick L Baehner, Steven Shak, Norman Wolmark. Assessment of estrogen receptor (ESR1) mRNA expression for prediction of extended aromatase inhibitor benefit in HR-positive breast cancer using NRG Oncology/NSABP B-42 [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 PD15-05.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Behavioral and health outcomes from the NRG Oncology/NSABP B-36 trial comparing two different adjuvant therapy regimens for early-stage node-negative breast cancer

BACKGROUND

The NSABP B-36 compared four cycles of doxorubicin and cyclophosphamide (AC) with six cycles of 5-fluorouracil, epirubicin, and cyclophosphamide (FEC-100) in node-negative early-stage breast cancer. A sub-study within B-36, focusing on symptoms, quality of life (QOL), menstrual history (MH), and cardiac function (CF) was conducted.

PATIENTS AND METHODS

Patients completed the QOL questionnaire at baseline, during treatment, and every 6 months through 36 months. FACT-B Trial Outcome Index (TOI), symptom severity, and SF-36 Vitality and Physical Functioning (PF) scales scores were compared between the two groups using a mixed model for repeated measures analysis. MH was collected at baseline and subsequently assessed if menstrual bleeding occurred within 12 months prior to randomization. Post-chemotherapy amenorrhea outcome was examined at 18 months and was defined as lack of menses in the preceding year. Logistic regression was used to test for association of amenorrhea and treatment. CF assessment was done at baseline and 12 months. Correlation analysis was used to address associations between changes in baseline and 12-month PF and concurrent CF changes measured by LVEF.

RESULTS

FEC-100 patients had statistically significantly lower TOI scores during chemotherapy (P = 0.02) and at 6 months (P < 0.001); lower Vitality score at 6 months (P < 0.01), and lower PF score during the first year than AC patients. There were no statistically significant QOL score differences between the two groups beyond 12 months. No significant differences in symptom severity between the two groups were observed. Rates of amenorrhea were significantly different between FEC-100 and AC (67.4% vs. 59.1%, P < 0.001). There was no association between changes in LVEF and PF (P = 0.38).

CONCLUSIONS

Statistically significant QOL differences between the two groups favored AC; however, the magnitude was small and unlikely to be clinically meaningful. There was a clinical and statistically significant difference in risk for amenorrhea, favoring AC.

TRIAL REGISTRY

NCT00087178; Date of registration: 07/08/2004.

Preservation of quality of life in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer treated with tucatinib or placebo when added to trastuzumab and capecitabine (HER2CLIMB trial)

AIMS

In HER2CLIMB, tucatinib significantly improved progression-free and overall survival in patients with human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer. We evaluated the impact of tucatinib on health-related quality of life (HR-QoL) in HER2CLIMB.

METHODS

Patients were randomised 2:1 to tucatinib or placebo combined with trastuzumab and capecitabine. Starting with protocol version 7, the EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) questionnaire and EQ visual analogue scale (VAS) were administered at day 1 of cycle 1, every two cycles during cycles 3-9, every three cycles during cycle 12 and thereafter and at each patient's 30-day follow-up visit.

RESULTS

Among 364 patients eligible for HR-QoL assessment, 331 (91%) completed ≥1 assessment. EQ-VAS scores were similar for both arms at baseline and maintained throughout treatment. EQ-5D-5L scores were similar between the treatment arms, stable throughout therapy and worsened after discontinuing treatment. Risk of meaningful deterioration (≥7 points) on EQ-VAS was reduced 19% in the tucatinib vs. placebo arm (hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.55, 1.18); the median (95% CI) time to deterioration was not reached in the tucatinib arm and was 5.8 months (4.3, -) in the placebo arm. Among patients with brain metastases (n = 164), risk of meaningful deterioration on EQ-VAS was reduced 49% in the tucatinib arm (HR: 0.51; 95% CI: 0.28, 0.93); the median (95% CI) time to deterioration was not reached in the tucatinib arm and was 5.5 months (4.2, -) in the placebo arm.

CONCLUSIONS

HR-QoL was preserved for patients with HER2+ metastatic breast cancer who were treated with tucatinib added to trastuzumab and capecitabine and maintained longer with tucatinib therapy than without it among those with brain metastases.

CLINICAL TRIAL REGISTRATION

NCT02614794.

MAF Amplification and Adjuvant Clodronate Outcomes in Early-Stage Breast Cancer in NSABP B-34 and Potential Impact on Clinical Practice

Background

The Adjuvant Zoledronic Acid (ZA) study in early breast cancer (AZURE) showed correlation between a nonamplified MAF gene in the primary tumor and benefit from adjuvant ZA. Adverse ZA outcomes occurred in MAF-amplified patients. NSABP B-34 is a validation study.

Methods

A retrospective analysis of MAF gene status in NSABP B-34 was performed. Eligible patients were randomly assigned to standard adjuvant systemic treatment plus 3 years oral clodronate (1600 mg/daily) or placebo. Tumors were tested for MAF gene amplification and analyzed for their relationship to clodronate for disease-free survival (DFS) and overall survival (OS) in MAF nonamplified patients. All statistical tests were 2-sided .

Results

MAF status was assessed in 2533 available primary tumor samples from 3311 patients. Of these, 37 withdrew consent; in 77 samples, no tumor was found; 536 assays did not meet quality standards, leaving 1883 (77.8%) evaluable for MAF assay by fluorescence in situ hybridization (947 from placebo and 936 from clodronate arms). At 5 years, in MAF nonamplified patients receiving clodronate, DFS improved by 30% (hazard ratio = 0.70, 95% confidence interval = 0.51 to 0.94; P = .02). OS improved at 5 years (hazard ratio = 0.59, 95% confidence interval = 0.37 to 0.93; P = .02) remaining statistically significant for clodronate throughout study follow-up. Conversely, adjuvant clodronate in women with MAF-amplified tumors was not associated with benefit but rather possible harm in some subgroups. Association between MAF status and menopausal status was not seen.

Conclusions

Nonamplified MAF showed statistically significant benefits (DFS and OS) with oral clodronate, supporting validation of the AZURE study.

Breast Cancer Index (BCI) and prediction of benefit from extended aromatase inhibitor (AI) therapy (tx) in HR+ breast cancer: NRG oncology/NSABP B-42

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Background: The BCI HOXB13/IL17BR ratio (BCI-H/I) has been shown to predict endocrine tx (ET) and extended ET (EET) benefit. We examined the effect of BCI-H/I for EET benefit prediction in NSABP B-42, evaluating extended letrozole tx (ELT) in HR+ breast cancer patients (pts) who completed 5 yrs of ET. Methods: All pts with available primary tumor tissue were eligible. Primary endpoint was recurrence-free interval (RFI). Secondary endpoints were distant recurrence (DR), breast cancer-free interval (BCFI), and disease-free survival (DFS). Stratified Cox proportional hazards model was used. Due to a non-proportional effect of ELT on DR, time-dependent secondary analyses (≤4y, >4y) were performed. Likelihood ratio test evaluated treatment by BCI-H/I interaction. Results: In 2,179 pts analyzed (60% N0; 62% AI only; 80% HER2-), 45% were BCI-H/I-High and 55% BCI-H/I-Low. ELT showed an absolute 10y benefit of 1.6% for RFI (HR=0.77, 95% CI 0.57-1.05, p=0.10) (BCI-H/I-Low: 1.1% [HR=0.69, 0.43-1.11, p=0.13]; BCI-H/I-High: 2.4% [HR=0.83, 0.55-1.26, p=0.38]; interaction p=0.55). There was no statistically significant ELT by BCI-H/I interaction for BCFI (BCI-H/I-Low: HR=0.53, 0.36-0.78, p=0.001; BCI-H/I-High: HR=0.85, 0.60-1.21, p=0.36; interaction p=0.07) or for DFS (BCI-H/I-Low: HR=0.75, 0.58-0.95, p=0.017; BCI-H/I-High: HR=0.81, 0.64-1.04, p=0.09; interaction p=0.62). Before 4y, there was no statistically significant ELT benefit on DR in either BCI-H/I group. After 4y, BCI-H/I-High pts had statistically significant ELT benefit on DR (HR: 0.29, 0.12-0.69, p=0.003), while BCI-H/I-Low pts were less likely to benefit (HR: 0.68, 0.33-1.39, p=0.28) (interaction p=0.14). Conclusions: BCI-H/I prediction of ELT benefit on RFI was not confirmed. In time-dependent DR analyses, BCI-H/I-High pts had statistically significant benefit from ELT after 4y, while BCI-H/I-Low pts did not. Observed ELT benefit on BCFI in BCI-H/I-Low pts was primarily driven by second primary breast cancers. Additional follow-up is needed to further characterize BCI-H/I predictive ability in this study. Support: U10CA180868, -180822, U24CA196067; Novartis; Biotheranostics. Clinical trial information: NCT00382070. [Table: see text]

NRG Oncology/NSABP B-47 menstrual history study: impact of adjuvant chemotherapy with and without trastuzumab

The NRG Oncology/NSABP B-47 menstrual history (MH) study examined trastuzumab effects on menstrual status and associated circulating reproductive hormones. MH was evaluated by questions related to hysterectomy, oophorectomy, and reported menstrual changes. Pre/perimenopausal women were assessed at entry, 3, 6, 12, 18, 24, 30, and 36 months. Consenting women had estradiol and FSH measurement at entry, 3, 6, 12, 18, and 24 months. Logistic regression determined predictors of amenorrhea and hormone levels at 12, 24, and 36 months. Between 2/8/2011 and 2/10/2015, 3270 women with node-positive/high-risk node-negative HER2-low breast cancer were enrolled. There were 1,458 women enrolled in the MH study; 1231 consented to baseline blood samples. Trastuzumab did not contribute to a higher amenorrhea rate. Amenorrhea predictors were consistent with earlier studies; however, to our knowledge, this is the largest prospective study to include serial reproductive hormone measurements to 24 months and clinical amenorrhea reports to 36 months. These data can help to counsel patients regarding premature menopause risk.

Utility of the 70-gene MammaPrint assay for prediction of benefit from extended letrozole therapy (ELT) in the NRG Oncology/NSABP B-42 trial

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Background: The 70-gene MammaPrint (MP) assay predicts risk of distant recurrence (DR) in hormone-receptor positive early-stage breast cancer and classifies cancers as Low Risk or High Risk. NSABP B-42 evaluated ELT in patients (pts) who had completed 5 yrs of adjuvant endocrine therapy (tx). The primary objective was to determine the utility of MP to identify pts enrolled in NSABP B-42 who are likely to benefit from ELT. Methods: A total of 1,866 pts from B-42 had available MP results. Primary endpoint is DR. Secondary endpoints are disease-free survival (DFS) and breast cancer-free interval (BCFI). For the primary analysis, pts were classified as High Risk (MP-H) (MP score ≤0.000) or Low Risk (MP-L) (MP score > 0.000). Exploratory analyses were performed for MP-L subcategories: MP Ultralow Risk (MP-UL) (MP score > 0.355) and MP-L but not MP-UL (MP-LNUL) (MP score > 0.000, ≤0.355). Likelihood ratio test based on stratified Cox proportional hazards (PH) model was used for treatment by risk group interaction. Stratified log-rank test was used to compare treatment groups. Hazard ratios and 95% CI were computed based on the stratified Cox PH model. Results: Among 1,866 pts, 706 (38%) were MP-H and 1,160 (62%) were MP-L. Of the MP-L, 252 (22%) were MP-UL. There were no significant differences in the distribution of patient and tumor characteristics between the MP group and the rest of the B-42 cohort, except for HER2 status. ELT effect was more pronounced in the MP cohort than in the overall B-42 population. For DR, there was statistically significant ELT benefit in MP-L (HR = 0.43, 95% CI 0.25-0.74, p = 0.002), but not MP-H (HR = 0.65, 0.34-1.24, p = 0.19) (interaction p = 0.38). For DFS, there was statistically significant ELT benefit in MP-L, but not MP-H (interaction p = 0.015). Similar findings were observed for BCFI (interaction p = 0.006). Within subcategories of MP-L, there was statistically significant ELT benefit in MP-LNUL, but not in MP-UL for all three endpoints, however the power in MP-UL was limited due to low number of pts (Table). Clinical trial information: 00382070. Conclusions: Statistically significant ELT benefit was observed for MP-L, but not MP-H. The treatment by risk group interaction was not statistically significant for DR, but it was for DFS and BCFI. The benefit appears to be stronger in MP-LNUL than in MP-UL. NCT: 00382070. Support: U10CA180868, -180822, U24CA196067; Novartis; Agendia.[Table: see text]

Antimullerian Hormone as a Serum Biomarker for Risk of Chemotherapy-Induced Amenorrhea

Antimullerian hormone (AMH) is a promising biomarker for ovarian reserve. In this study, we assessed AMH before and 1 year after initiation of adjuvant chemotherapy on National Surgical Adjuvant Breast and Bowel Project (NSABP)/NRG Oncology B-47 in female participants aged 42 years and younger (median age = 39 years). At baseline, median AMH was 1.2 ng/mL; 13 (4.7%) values were less than 0.1 ng/mL (the threshold for detectable levels, in the perimenopause and menopause range), and 57 values (20.6%) were less than 0.5 ng/mL. At 1 year, 215 (77.6%) were less than 0.1 ng/mL, and 264 (95.3%) were less than 0.5 ng/mL. Postchemotherapy menses were reported by 46.2% of participants. Multivariable logistic regression found that the odds of having postchemotherapy menses increased with younger age, higher body mass index, and higher prechemotherapy AMH, but not by trastuzumab administration or by the choice of chemotherapy (doxorubicin-cyclophosphamide followed by paclitaxel vs docetaxel-cyclophosphamide). We conclude that higher prechemotherapy AMH predicts a lower risk of chemotherapy-induced amenorrhea and that AMH 1 year after chemotherapy initiation is not informative in this setting because it is likely to be very low.

Stromal Tumor-infiltrating Lymphocytes in NRG Oncology/NSABP B-31 Adjuvant Trial for Early-Stage HER2-Positive Breast Cancer

We retrospectively assessed association of stromal tumor-infiltrating lymphocytes (sTILs) with clinical outcomes and molecular variables reportedly predictive of trastuzumab-benefit in National Surgical Adjuvant Breast and Bowel Project B-31 (N = 2130). sTILs were assessed in 1581 eligible B-31 cases utilizing all available hematoxylin and eosin slides. Mean concordance between main reviewer and six other pathologists was 90.8% in 100 cases. Cox regressions were used to calculate hazard ratios (HRs). In chemotherapy and trastuzumab added to chemotherapy arms, increases in sTILs, as a semicontinuous variable (combined arms HR = 0.42, 95% confidence interval = 0.27 to 0.64, two-sided P < .001) or as lymphocyte-predominant breast cancer with more than 50% sTILs (combined arms HR = 0.65, 95% confidence interval = 0.49 to 0.86, two-sided P = .003) were statistically significantly associated with improved disease-free survival. There was no association of sTILs with trastuzumab benefit. However, higher sTILs were statistically significantly associated with higher trastuzumab benefit groups by 8-gene prediction model (two-sided P < .001). Neither PIK3CA mutations nor Fc-gamma-receptor polymorphisms were associated with sTILs. sTILs may have utility as a prognostic biomarker identifying HER2-positive early breast cancer at low recurrence risk.

Adjuvant endocrine therapy for breast cancer patients: impact of a health system outreach program to improve adherence

PURPOSE

Reports suggest that up to 50% of women with hormone receptor-positive (HR+) breast cancer (BC) do not complete the recommended 5 years of adjuvant endocrine therapy (AET). We examined the impact of an outreach program at Kaiser Permanente Northern California (KPNC) on adherence and discontinuation of AET among patients who initiated AET.

METHODS

We assembled a retrospective cohort of all KPNC patients diagnosed with HR+, stage I-III BC initiating AET before (n = 4287) and after (n = 3580) implementation of the outreach program. We compared adherence proportions and discontinuation rates before and after program implementation, both crude and adjusted for age, race/ethnicity, education, income, and stage. We conducted a pooled analysis of data from six Cancer Research Network (CRN) sites that had not implemented programs for improving AET adherence, using identical methods and time periods, to assess possible secular trends.

RESULTS

In the pre-outreach period, estimated adherence in years 1, 2, and 3 following AET initiation was 75.2%, 71.0%, and 67.3%; following the outreach program, the estimates were 79.4%, 75.6%, and 72.2% (p-values < .0001 for pairwise comparisons). Results were comparable after adjusting for clinical and demographic factors. The estimated cumulative incidence of discontinuation was 0.22 (0.21-0.24) and 0.18 (0.17-0.19) at 3 years for pre- and post-outreach groups (p-value < .0001). We found no evidence of an increase in adherence between the study periods at the CRN sites with no AET adherence program.

CONCLUSION

Adherence and discontinuation after AET initiation improved modestly following implementation of the outreach program.

NSABP B-47/NRG Oncology Phase III Randomized Trial Comparing Adjuvant Chemotherapy With or Without Trastuzumab in High-Risk Invasive Breast Cancer Negative for HER2 by FISH and With IHC 1+ or 2

PURPOSE

Adjuvant trastuzumab reduces invasive breast cancer (IBC) recurrence and risk for death in patients with HER2-amplified or overexpressing IBC. A subset of patients in the landmark trastuzumab adjuvant trials who originally tested HER2-positive but were HER2-negative by central HER2 testing appeared to possibly benefit from trastuzumab. The objective for the NSABP B-47 trial was to determine whether the addition of trastuzumab to adjuvant chemotherapy (CRx) would improve invasive disease-free survival (IDFS) in patients with HER2-negative breast cancer.

PATIENTS AND METHODS

A total of 3,270 women with high-risk primary IBC were randomly assigned to CRx with or without 1 year of trastuzumab. Eligibility criteria included immunohistochemistry (IHC) score 1+ or 2+ with fluorescence in situ hybridization ratio (FISH) < 2.0 or, if ratio was not performed, HER2 gene copy number < 4.0. CRx was either docetaxel plus cyclophosphamide or doxorubicin and cyclophosphamide followed by weekly paclitaxel for 12 weeks.

RESULTS

At a median follow-up of 46 months, the addition of trastuzumab to CRx did not improve IDFS (5-year IDFS: 89.8% with CRx plus trastuzumab [CRxT] v 89.2% with CRx alone; hazard ratio [HR], 0.98; 95% CI, 0.76 to 1.25; P = .85). These findings did not differ by level of HER2 IHC expression, lymph node involvement, or hormone-receptor status. For distant recurrence-free interval, 5-year estimates were 92.7% with CRxT compared with 93.6% for CRx alone (HR, 1.10; 95% CI, 0.81 to 1.50; P = .55) and for overall survival (OS) were 94.8% with CRxT and 96.3% in CRx alone (HR, 1.33; 95% CI, 0.90 to 1.95; P = .15). There were no unexpected toxicities from the addition of trastuzumab to CRx.

CONCLUSION

The addition of trastuzumab to CRx did not improve IDFS, distant recurrence-free interval, or OS in women with non-HER2-overexpressing IBC. Trastuzumab does not benefit women without IHC 3+ or FISH ratio-amplified breast cancer.

Talazoparib in Patients with a Germline BRCA-Mutated Advanced Breast Cancer: Detailed Safety Analyses from the Phase III EMBRACA Trial

Background

In the EMBRACA phase III study (NCT01945775), talazoparib was associated with a significantly prolonged progression‐free survival (PFS) compared with physician's choice of chemotherapy (PCT) in germline BRCA1/2‐mutated HER2‐negative advanced breast cancer (ABC). Herein, the safety profile of talazoparib is explored in detail.

Materials and Methods

Overall, 412 patients received ≥1 dose of talazoparib (n = 286) or PCT (n = 126). Adverse events (AEs) were evaluated, including timing, duration, and potential overlap of selected AEs. The relationship between talazoparib plasma exposure and grade ≥3 anemia was analyzed. Time‐varying Cox proportional hazard models assessed the impact of dose reductions on PFS. Patient‐reported outcomes (PROs) in patients with common AEs and health resource utilization (HRU) were assessed in both treatment arms.

Results

The most common AEs with talazoparib were hematologic (195 [68.2%] patients) and typically occurred within the first 3–4 months of receiving talazoparib. Grade 3‐4 anemia lasted approximately 7 days for both arms. Overlapping grade 3‐4 hematologic AEs were infrequent with talazoparib. Higher talazoparib exposure was associated with grade ≥3 anemia. Permanent discontinuation of talazoparib due to hematologic AEs was low (<2%). A total of 150 (52.4%) patients receiving talazoparib had AEs associated with dose reduction. Hematologic toxicities were managed by supportive care medication (including transfusion) and dose modifications. Among patients with anemia or nausea and/or vomiting AEs, PROs favored talazoparib. After accounting for the treatment‐emergent period, talazoparib was generally associated with a lower rate of hospitalization and supportive care medication use compared with chemotherapy.

Conclusion

Talazoparib was associated with superior efficacy, favorable PROs, and lower HRU rate versus chemotherapy in gBRCA‐mutated ABC. Toxicities were manageable with talazoparib dose modification and supportive care.

Implications for Practice

Talazoparib was generally well tolerated in patients with germline BRCA‐mutated HER2‐negative advanced breast cancer in the EMBRACA trial. Common toxicities with talazoparib were primarily hematologic and infrequently resulted in permanent drug discontinuation (<2% of patients discontinued talazoparib due to hematologic toxicity). Hematologic toxicities typically occurred during the first 3–4 months of treatment and were managed by dose modifications and supportive care measures. A significant efficacy benefit, improved patient‐reported outcomes, lower rate of health resource utilization and a tolerable safety profile support incorporating talazoparib into routine management of germline BRCA‐mutated locally advanced/metastatic breast cancer.

Talazoparib is a viable option for patients with germline BRCA‐mutated advanced breast cancer. This article presents detailed safety analyses for talazoparib, as a follow‐up to reported results from the EMBRACA trial, to highlight patterns of toxicity compared with chemotherapy and to outline guidelines for management of talazoparib toxicity in clinical practice via dose modifications and/or standard supportive care.

Outcomes in Clinically Relevant Patient Subgroups From the EMBRACA Study: Talazoparib vs Physician's Choice Standard-of-Care Chemotherapy

Background

Talazoparib is a poly(adenosine diphosphate-ribose) polymerase inhibitor that causes death in cells with breast cancer susceptibility gene 1 or 2 (BRCA1/2) mutations.

Methods

EMBRACA (NCT01945775) was a randomized phase III study comparing efficacy, safety, and patient-reported outcomes (PROs) of talazoparib (1 mg) with physician’s choice of chemotherapy (PCT: capecitabine, eribulin, gemcitabine, vinorelbine) in locally advanced or metastatic breast cancer with a germline BRCA1/2 (gBRCA1/2) mutation. Prespecified patient subgroups were analyzed for progression-free survival, objective response, clinical benefit, duration of response, and safety. PROs were evaluated in hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2−) or triple-negative breast cancer (TNBC) subgroups.

Results

Of 431 patients, 287 were randomly assigned to talazoparib and 144 to PCT. Prespecified subgroup analyses showed prolonged progression-free survival with talazoparib (HR+/HER2−: hazard ratio = 0.47, 95% confidence interval = 0.32 to 0.71; TNBC: hazard ratio = 0.60, 95% confidence interval = 0.41 to 0.87) and greater objective response rate (odds ratio = 1.97 to 11.89), clinical benefit rate (odds ratio = 2.05 to 7.77), and duration of response with talazoparib in all subgroups. PROs in HR+/HER2− and TNBC subgroups showed consistent overall improvement and delay in time to definitive clinically meaningful deterioration with talazoparib vs PCT. Across subgroups, common adverse events included anemia, fatigue, and nausea with talazoparib and neutropenia, fatigue, and nausea with PCT. Seven patients (2.4%) receiving talazoparib had grade II alopecia and 22.7% had grade I alopecia.

Conclusions

Across all patient subgroups with gBRCA-mutated advanced breast cancer, talazoparib demonstrated clinically significant superiority in outcomes compared with PCT.

Use of letrozole after aromatase inhibitor-based therapy in postmenopausal breast cancer (NRG Oncology/NSABP B-42): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

The optimal duration of extended therapy with aromatase inhibitors in patients with postmenopausal breast cancer is unknown. In the NSABP B-42 study, we aimed to determine whether extended letrozole treatment improves disease-free survival after 5 years of aromatase inhibitor-based therapy in women with postmenopausal breast cancer.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial was done in 158 centres in the USA, Canada, and Ireland. Postmenopausal women with stage I-IIIA hormone receptor-positive breast cancer, who were disease-free after about 5 years of treatment with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor, were randomly assigned (1:1) to receive 5 years of letrozole (2·5 mg orally per day) or placebo. Randomisation was stratified by pathological node status, previous tamoxifen use, and lowest bone mineral density T score in the lumbosacral spine, total hip, or femoral neck. The primary endpoint was disease-free survival, defined as time from randomisation to breast cancer recurrence, second primary malignancy, or death, and was analysed by intention to treat. To adjust for previous interim analyses, the two-sided statistical significance level for disease-free survival was set at 0·0418. This study is registered with ClinicalTrials.gov, number NCT00382070, is active, and is no longer enrolling patients.

FINDINGS

Between Sept 28, 2006, and Jan 6, 2010, 3966 patients were randomly assigned to receive letrozole (n=1983) or placebo (n=1983). Follow-up information was available for 3903 patients for the analyses of disease-free survival. Median follow-up was 6·9 years (IQR 6·1-7·5). Letrozole treatment did not significantly improve disease-free survival (339 disease-free survival events were reported in the placebo group and 292 disease-free survival events were reported in the letrozole group; hazard ratio 0·85, 95% CI 0·73-0·999; p=0·048). 7-year disease-free survival estimate was 81·3% (95% CI 79·3-83·1) in the placebo group and 84·7% (82·9-86·4) in the letrozole group. The most common grade 3 adverse events were arthralgia (47 [2%] of 1933 patients in the placebo group vs 50 [3%] of 1941 patients in the letrozole group) and back pain (44 [2%] vs 38 [2%]). The most common grade 4 adverse event in the placebo group was thromboembolic event (eight [<1%]) and the most common grade 4 adverse events in the letrozole group were urinary tract infection, hypokalaemia, and left ventricular systolic dysfunction (four [<1%] each).

INTERPRETATION

After 5 years of aromatase inhibitor-based therapy, 5 years of letrozole therapy did not significantly prolong disease-free survival compared with placebo. Careful assessment of potential risks and benefits is required before recommending extended letrozole therapy to patients with early-stage breast cancer.

FUNDING

National Cancer Institute, Korea Health Technology R&D Project, Novartis.

National Cancer Institute Breast Cancer Steering Committee Working Group Report on Meaningful and Appropriate End Points for Clinical Trials in Metastatic Breast Cancer

PURPOSE

To provide evidence-based consensus recommendations on choice of end points for clinical trials in metastatic breast cancer, with a focus on biologic subtype and line of therapy.

METHODS

The National Cancer Institute Breast Cancer Steering Committee convened a working group of breast medical oncologists, patient advocates, biostatisticians, and liaisons from the Food and Drug Administration to conduct a detailed curated systematic review of the literature, including original reports, reviews, and meta-analyses, to determine the current landscape of therapeutic options, recent clinical trial data, and natural history of four biologic subtypes of breast cancer. Ongoing clinical trials for metastatic breast cancer in each subtype also were reviewed from ClinicalTrials.gov for planned primary end points. External input was obtained from the pharmaceutic/biotechnology industry, real-world clinical data specialists, experts in quality of life and patient-reported outcomes, and combined metrics for assessing magnitude of clinical benefit.

RESULTS

The literature search yielded 146 publications to inform the recommendations from the working group.

CONCLUSION

Recommendations for appropriate end points for metastatic breast cancer clinical trials focus on biologic subtype and line of therapy and the magnitude of absolute and relative gains that would represent meaningful clinical benefit.

Atezolizumab Treatment Beyond Progression in Advanced NSCLC: Results From the Randomized, Phase III OAK Study

INTRODUCTION

Cancer immunotherapy may alter tumor biology such that treatment effects can extend beyond radiographic progression. In the randomized, phase III OAK study of atezolizumab (anti-programmed death-ligand 1) versus docetaxel in advanced NSCLC, overall survival (OS) benefit with atezolizumab was observed in the overall patient population, without improvement in objective response rate (ORR) or progression-free survival (PFS). We examine the benefit-risk of atezolizumab treatment beyond progression (TBP).

METHODS

Eight hundred fifty patients included in the OAK primary efficacy analysis were evaluated. Atezolizumab was continued until loss of clinical benefit. Docetaxel was administered until Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) disease progression (PD)/unacceptable toxicity; no crossover to atezolizumab was allowed. ORR, PFS, post-PD OS, target lesion change, and safety were evaluated.

RESULTS

In atezolizumab-arm patients, ORR was 16% versus 14% and median PFS was 4.2 versus 2.8 months per immune-modified RECIST versus RECIST v1.1. The median post-PD OS was 12.7 months (95% confidence interval [CI]: 9.3-14.9) in 168 atezolizumab-arm patients continuing TBP, 8.8 months (95% CI: 6.0-12.1) in 94 patients switching to nonprotocol therapy, and 2.2 months (95% CI: 1.9-3.4) in 70 patients receiving no further therapy. Of the atezolizumab TBP patients, 7% achieved a post-progression response in target lesions and 49% had stable target lesions. Atezolizumab TBP was not associated with increased safety risks.

CONCLUSIONS

Within the limitations of this retrospective analysis, the post-PD efficacy and safety data from OAK are consistent with a positive benefit-risk profile of atezolizumab TBP in patients performing well clinically at the time of PD.

Abstract A41: Analytic validation and clinical feasibility of a next-generation sequencing assay to assess tumor mutational burden from blood (bTMB) as a biomarker for anti-PD-L1 response in NSCLC

Background: The need to identify biomarkers that predict benefit to checkpoint inhibitor therapies has led to the discovery and development of tumor mutational burden (TMB), a measure of potential tumor neoantigenicity derived from tissue biopsies that has shown clinical utility across a range of tumor types. A significant fraction of patients, however, are not candidates for tissue biopsies, presenting the need for blood-based methods to determine TMB. Here we describe the development of an assay to identify TMB from cell-free DNA derived from blood (bTMB). We present the analytic validation and clinical feasibility data that support the application of bTMB in a prospective clinical trial, BFAST (NCT03178552), evaluating the anti-PD-L1 agent atezolizumab in patients with non-small cell lung cancer (NSCLC).

Methods: The bTMB assay surveys somatic base substitutions down to 0.5% allele frequency across 394 genes from as little as 1% tumor content in a cell free DNA (cfDNA) sample derived from blood. Analytic validation was focused on establishing accuracy and precision of the bTMB measurement, as well as the minimum amount of cell-free and circulating tumor DNA required to make precise and reliable bTMB calls. The accuracy of two bTMB cutoffs was established against TMB derived from FoundationOne, an analytically validated TMB platform. Precision was evaluated by comparing the reproducibility of bTMB calls across replicate samples. We also retrospectively analyzed plasma samples from the OAK (NCT02008227) and POPLAR (NCT01903993) trials with the bTMB assay to determine the association of bTMB with atezolizumab clinical activity. The biomarker evaluable population (BEP) included 211 patients in POPLAR (intention-to-treat [ITT] =287) and 583 patients in OAK (excludes patients with known EGFR/ALK mutations; ITT=850), with blood samples available for targeted genomic sequencing. Assay positivity was defined as the presence of a number of somatic base substitutions greater than or equal to the bTMB cutoffs.

Results: The average positive percent agreement (PPA), negative percent agreement (NPA) and positive predictive value (PPV) across the bTMB cutoffs were 95%, 100% and 100%, respectively. The average precision was 96%, with a coefficient of variation of 7%. The assay limit of detection was defined as 1% tumor content in at least 20 ng of cfDNA. In POPLAR, improved progression-free survival (PFS) and overall survival (OS) hazard ratios (HRs) with atezolizumab vs docetaxel were observed for patients with bTMB at or above a range of bTMB thresholds compared with the ITT and BEP populations. In OAK, PFS benefit with atezolizumab vs docetaxel was observed at bTMB thresholds ≥10 (cut point ≥10: HR 0.73; n=251) compared with BEP (HR 0.87, 95% CI 0.73-1.04; n=585). bTMB did not correlate with PD-L1 expression as measured by VENTANA SP142 immunohistochemistry.

Conclusions: We have developed and analytically validated a blood-based assay to determine TMB with high accuracy and precision, using as little as 1% tumor content in a sample with 20 ng of cfDNA. Retrospective analyses from POPLAR and OAK data provide the first demonstrations that blood-based measurement of TMB may be associated with atezolizumab clinical efficacy in second-line NSCLC. Thus, the bTMB assay may provide a non-invasive biomarker to identify patients who derive clinical benefit from single agent PD-1/PD-L1 inhibition. Prospective studies using bTMB are currently ongoing in patients with first-line NSCLC, including BFAST and B-F1RST (NCT02848651).

Citation Format: Daniel S. Lieber, Emily White, Jacob Silterra, Shan Zhong, Tina Brennan, Michael Coyne, Mark Kennedy, David R. Gandara, Marcin Kowanetz, Sarah M. Paul, Erica Schleifman, Yan Li, Achim Rittmeyer, Louis Fehrenbacher, Lukas Amler, Todd Riehl, Craig Cummings, Priti S. Hegde, Wei Zou, Alan Sandler, Marcus Ballinger, Tony Mok, David S. Shames, Doron Lipson, Christine Malboeuf, David Fabrizio. Analytic validation and clinical feasibility of a next-generation sequencing assay to assess tumor mutational burden from blood (bTMB) as a biomarker for anti-PD-L1 response in NSCLC [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A41.

Talazoparib in Patients with Advanced Breast Cancer and a Germline BRCA Mutation

BACKGROUND

The poly(adenosine diphosphate-ribose) inhibitor talazoparib has shown antitumor activity in patients with advanced breast cancer and germline mutations in BRCA1 and BRCA2 ( BRCA1/2).

METHODS

We conducted a randomized, open-label, phase 3 trial in which patients with advanced breast cancer and a germline BRCA1/2 mutation were assigned, in a 2:1 ratio, to receive talazoparib (1 mg once daily) or standard single-agent therapy of the physician's choice (capecitabine, eribulin, gemcitabine, or vinorelbine in continuous 21-day cycles). The primary end point was progression-free survival, which was assessed by blinded independent central review.

RESULTS

Of the 431 patients who underwent randomization, 287 were assigned to receive talazoparib and 144 were assigned to receive standard therapy. Median progression-free survival was significantly longer in the talazoparib group than in the standard-therapy group (8.6 months vs. 5.6 months; hazard ratio for disease progression or death, 0.54; 95% confidence interval [CI], 0.41 to 0.71; P<0.001). The interim median hazard ratio for death was 0.76 (95% CI, 0.55 to 1.06; P=0.11 [57% of projected events]). The objective response rate was higher in the talazoparib group than in the standard-therapy group (62.6% vs. 27.2%; odds ratio, 5.0; 95% CI, 2.9 to 8.8; P<0.001). Hematologic grade 3-4 adverse events (primarily anemia) occurred in 55% of the patients who received talazoparib and in 38% of the patients who received standard therapy; nonhematologic grade 3 adverse events occurred in 32% and 38% of the patients, respectively. Patient-reported outcomes favored talazoparib; significant overall improvements and significant delays in the time to clinically meaningful deterioration according to both the global health status-quality-of-life and breast symptoms scales were observed.

CONCLUSIONS

Among patients with advanced breast cancer and a germline BRCA1/2 mutation, single-agent talazoparib provided a significant benefit over standard chemotherapy with respect to progression-free survival. Patient-reported outcomes were superior with talazoparib. (Funded by Medivation [Pfizer]; EMBRACA ClinicalTrials.gov number, NCT01945775 .).

Two-Year Trends of Taxane-Induced Neuropathy in Women Enrolled in a Randomized Trial of Acetyl-L-Carnitine (SWOG S0715)

Background

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and disabling side effect of taxanes. Acetyl-L-carnitine (ALC) was unexpectedly found to increase CIPN in a randomized trial. We investigated the long-term patterns of CIPN among patients in this trial.

Methods

S0715 was a randomized, double-blind, multicenter trial comparing ALC (1000 mg three times a day) with placebo for 24 weeks in women undergoing adjuvant taxane-based chemotherapy for breast cancer. CIPN was measured by the 11-item neurotoxicity (NTX) component of the FACT-Taxane scale at weeks 12, 24, 36, 52, and 104. We examined NTX scores over two years using linear mixed models for longitudinal data. Individual time points were examined using linear regression. Regression analyses included stratification factors and the baseline score as covariates. All statistical tests were two-sided.

Results

Four-hundred nine subjects were eligible for evaluation. Patients receiving ALC had a statistically significantly (P = .01) greater reduction in NTX scores (worse CIPN) of -1.39 points (95% confidence interval [CI] = -2.48 to -0.30) than the placebo group. These differences were particularly evident at weeks 24 (-1.68, 95% CI = -3.02 to -0.33), 36 (-1.37, 95% CI = -2.69 to -0.04), and 52 (-1.83, 95% CI = -3.35 to -0.32). At 104 weeks, 39.5% on the ALC arm and 34.4% on the placebo arm reported a five-point (10%) decrease from baseline. For both treatment groups, 104-week NTX scores were statistically significantly different compared with baseline (P < .001).

Conclusions

For both groups, NTX scores were reduced from baseline and remained persistently low. Twenty-four weeks of ALC therapy resulted in statistically significantly worse CIPN over two years. Understanding the mechanism of this persistent effect may inform prevention and treatment strategies. Until then, the potential efficacy and harms of commonly used supplements should be rigorously studied.

Updated Efficacy Analysis Including Secondary Population Results for OAK: A Randomized Phase III Study of Atezolizumab versus Docetaxel in Patients with Previously Treated Advanced Non-Small Cell Lung Cancer

INTRODUCTION

The efficacy and safety of atezolizumab versus the efficacy and safety of docetaxel as second- or third-line treatment in patients with advanced NSCLC in the primary (n = 850) and secondary (n = 1225) efficacy populations of the randomized phase III OAK study (respectively referred to as the intention-to-treat [ITT] 850 [ITT850] and ITT1225) at an updated data cutoff were assessed.

METHODS

Patients received atezolizumab, 1200 mg, or docetaxel, 75 mg/m², intravenously every 3 weeks until loss of clinical benefit or disease progression, respectively. The primary end point was overall survival (OS) in the ITT population and programmed death-ligand 1-expressing subgroup. A sensitivity analysis was conducted to evaluate the impact of subsequent immunotherapy use in the docetaxel arm on the observed survival benefit with atezolizumab.

RESULTS

Atezolizumab demonstrated an OS benefit versus docetaxel in the updated ITT850 (hazard ratio [HR] = 0.75, 95% confidence interval: 0.64-0.89, p = 0.0006) and the ITT1225 (HR = 0.80, 95% confidence interval: 0.70-0.92, p = 0.0012) after minimum follow-up times of 26 and 21 months, respectively. Improved survival with atezolizumab was observed across programmed death-ligand 1 and histological subgroups. In the immunotherapy sensitivity analysis, the relative OS benefit with atezolizumab was slightly greater in the ITT850 (HR = 0.69) and ITT1225 (HR = 0.74) than the conventional OS estimate. Fewer patients receiving atezolizumab experienced grade 3 or 4 treatment-related adverse events (14.9%) than did patients receiving docetaxel (42.4%); no grade 5 adverse events related to atezolizumab were observed.

CONCLUSIONS

The results of the updated ITT850 and initial ITT1225 analyses were consistent with those of the primary efficacy analysis demonstrating survival benefit with atezolizumab versus with docetaxel. Atezolizumab continued to demonstrate a favorable safety profile after longer treatment exposure and follow-up.

Abstract P5-22-07: Upgrade to high risk lesions, in situ and invasive cancer among women with benign papillary lesions diagnosed on image-guided core needle biopsy (IGCNB)

Background: Currently there is no consensus regarding the management of benign papillary breast lesions diagnosed on IGCNB. Recommendations vary as to whether all IGCNB papillary lesions require surgical excision or if IGCNB alone is adequate to confirm a benign diagnosis and patients can be followed with imaging.

Aims: To estimate percentage of patients with benign papilloma on IGNB who on surgical excision are upgraded to high risk lesion, in situ or invasive cancer and to identify patient, imaging, and/or pathologic features that are predictive of upgrade.

Methods: We conducted a study of 407 patients within Kaiser Permanente Northern California (KPNC) diagnosed with benign papillary breast lesions on IGCNB in 2012 and 2013. KPNC is a large integrated health care delivery system, racially and ethnically diverse, and representative of the underlying population. Patients were excluded from study if they were &lt; 18 years, had atypia on IGCNB, had a prior history of breast cancer or high risk lesion, had a hereditary risk for developing breast cancer, or were noted to have papillomatosis or an incidental papilloma, or the target lesion was calcifications. Patients who did not have surgical excision of the IGCNB papilloma were followed for at least 2 years. Outcomes included in situ/invasive cancer and high risk lesions (atypical ductal or lobular hyperplasia, lobular carcinoma in-situ or papilloma with atypia). Outcomes were evaluated by review of medical records, including radiology, pathology, and surgical reports. The KPNC cancer registry and record review was used to exclude patients with a history of cancer.

Results: Among patients with benign papillary lesions, the average age was 56.4 years (range 20-93). Approximately 60% of lesions were 1 cm or less and 50% were centrally located (within 2 cm of nipple). There were 327 patients (80%) with surgical excision within 10 months of IGCNB, 61 patients (15%) with no surgical excision but follow-up imaging, and 19 patients (5%) with no surgery or follow-up imaging. Patients with and without surgical excision generally had similar age, breast density, and lesion location. However, surgical excision was more common among women with larger lesions. Among women with surgical excision, 9.5% (95% CI 6.3-12.7%) had a high risk lesion, 3.4% (95% CI 1.4-5.3-%) had an in situ lesion and 2.4% (95% CI 0.8-4.1%) had invasive cancer (all node negative). Less than 3% of women under 50 years, presenting with nipple discharge or with lesions less than 1 cm had invasive cancer on surgical excision. In contrast, over 10% of women with lesions greater than 1 cm, a palpable mass, or with lesions 5 or more cm from the nipple had invasive cancer on surgical excision. There were no cancers diagnosed among the 61 women followed by imaging; although 1 woman was upgraded to a high risk lesion.

Conclusions: In this large cohort of patients with benign papillary lesions on IGCNB, less than 3% had an invasive cancer on surgical excision. Upgrade was most common among patients with larger lesions, a palpable mass or lesions distant from the nipple and least common among women less than 50 years, with small lesions or presenting with nipple discharge.

Citation Format: Kuehner G, Darbinian JA, Butler S, Chang S, Fehrenbacher L, Chen R, Habel LA, Axelsson K. Upgrade to high risk lesions, in situ and invasive cancer among women with benign papillary lesions diagnosed on image-guided core needle biopsy (IGCNB) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-07.

Long-term Peripheral Neuropathy in Breast Cancer Patients Treated With Adjuvant Chemotherapy: NRG Oncology/NSABP B-30

Background

The long-term effects of chemotherapy are sparsely reported. Peripheral neuropathy (PN) is one of the most frequent toxicities associated with taxane use for the treatment of early-stage breast cancer. We investigated the impact of the three different docetaxel-based regimens and patient characteristics on long-term, patient-reported outcomes of PN and the impact of PN on long-term quality of life (QOL).

Methods

The National Surgical Adjuvant Breast and Bowel Project Protocol B-30 was a randomized trial comparing sequential doxorubicin (A) and cyclophosphamide (C) followed by docetaxel (T) (AC→T), concurrent ACT, or AT in women with node-positive, early-stage breast cancer. The AC→T group had a higher cumulative dose of T. PN was one of the symptoms assessed in a QOL substudy. Statistical methods included simple and mixed ordinal logistic regression and general linear models. All statistical tests were two-sided.

Results

Of 1512 patients, 41.9% reported PN two years after treatment initiation. Treatment with AT and ACT was associated with less severe long-term PN compared with AC→T (odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.35 to 0.58; OR = 0.59, 95% CI = 0.46 to 0.75). Preexisting PN, older age, obesity, mastectomy, and greater number of positive nodes were also associated with higher risk of long-term PN. Patients who reported worse PN symptoms at 24 months had statistically significantly worse QOL (Ptrend < .001).

Conclusions

The administration of docetaxel is associated with long-term PN. The lower rate of long-term PN in AT and ACT patients might be an important consideration in supporting choosing these therapies for individuals with preexisting neuropathic symptoms or other risk factors for neuropathy.

Modernizing Clinical Trial Eligibility Criteria: Recommendations of the American Society of Clinical Oncology–Friends of Cancer Research Organ Dysfunction, Prior or Concurrent Malignancy, and Comorbidities Working Group

Purpose

Patients with organ dysfunction, prior or concurrent malignancies, and comorbidities are often excluded from clinical trials. Excluding patients on the basis of these factors results in clinical trial participants who are healthier and younger than the overall population of patients with cancer.

Methods

ASCO and Friends of Cancer Research established a multidisciplinary working group that included experts in trial design and conduct to examine how eligibility criteria could be more inclusive. The group analyzed current eligibility criteria; conducted original data analysis; considered safety concerns, potential benefits, research, and potential hurdles of this approach through discussion; and reached consensus on recommendations regarding updated eligibility criteria that prioritize inclusiveness without compromising patient safety.

Results

If renal toxicity and clearance are not of direct treatment-related concern, then patients with lower creatinine clearance values of > 30 mL/min should be included in trials. Inclusion of patients with mild to moderate hepatic dysfunction may be possible when the totality of the available nonclinical and clinical data indicates that inclusion is safe. Ejection fraction values should be used with investigator assessment of a patient’s risk for heart failure to determine eligibility. Patients with laboratory parameters out of normal range as a result of hematologic disease should be included in trials. Measures of patient functional status should be included in trials to better assess fit versus frail patients.

Conclusion

Expanding inclusion of these patients will increase the number and diversity of patients in clinical trials and result in a more appropriate population of patients.

Randomized, Multicenter, Placebo-Controlled Clinical Trial of Duloxetine Versus Placebo for Aromatase Inhibitor-Associated Arthralgias in Early-Stage Breast Cancer: SWOG S1202

Purpose Adherence to aromatase inhibitor (AI) therapy for early-stage breast cancer is limited by AI-associated musculoskeletal symptoms (AIMSS). Duloxetine is US Food and Drug Administration approved for treatment of multiple chronic pain disorders. We hypothesized that treatment of AIMSS with duloxetine would improve average joint pain compared with placebo. Methods This randomized, double-blind, phase III trial included AI-treated postmenopausal women with early-stage breast cancer and who had average joint pain score of ≥ 4 out of 10 that developed or worsened since AI therapy initiation. Patients were randomly assigned 1:1 to duloxetine or placebo for 13 weeks. The primary end point was average joint pain through 12 weeks, examined using multivariable linear mixed models, adjusted for stratification factors (baseline pain score of 4 to 6 v 7 to 10 and prior taxane use). Clinically significant change in average pain was defined as a ≥ 2-point decrease from baseline. Results Of 299 enrolled patients, 127 patients treated with duloxetine and 128 who received placebo were evaluable for the primary analysis. By 12 weeks, the average joint pain score was 0.82 points lower for patients who received duloxetine compared with those who received placebo (95% CI, -1.24 to -0.40; P = .0002). Similar patterns were observed for worst joint pain, joint stiffness, pain interference, and functioning. Rates of adverse events of any grade were higher in the duloxetine-treated group (78% v 50%); rates of grade 3 adverse events were similar. Conclusion Results of treatment with duloxetine for AIMSS were superior to those of placebo among women with early-stage breast cancer, although it resulted in more frequent low-grade toxicities.

Long-Term Follow-Up of Cardiac Function and Quality of Life for Patients in NSABP Protocol B-31/NRG Oncology: A Randomized Trial Comparing the Safety and Efficacy of Doxorubicin and Cyclophosphamide (AC) Followed by Paclitaxel With AC Followed by Paclitaxel and Trastuzumab in Patients With Node-Positive Breast Cancer With Tumors Overexpressing Human Epidermal Growth Factor Receptor 2

Purpose Early cardiac toxicity is a risk associated with adjuvant chemotherapy plus trastuzumab. However, objective measures of cardiac function and health-related quality of life are lacking in long-term follow-up of patients who remain cancer free after completion of adjuvant treatment. Patients and Methods Patients in NSABP Protocol B-31 received anthracycline and taxane chemotherapy with or without trastuzumab for adjuvant treatment of node-positive, human epidermal growth factor receptor 2-positive early-stage breast cancer. A long-term follow-up assessment was undertaken for patients who were alive and disease free, which included measurement of left ventricular ejection fraction by multigated acquisition scan along with patient-reported outcomes using the Duke Activity Status Index (DASI), the Medical Outcomes Study questionnaire, and a review of current medications and comorbid conditions. Results At a median follow-up of 8.8 years among eligible participants, five (4.5%) of 110 in the control group and 10 (3.4%) of 297 in the trastuzumab group had a > 10% decline in left ventricular ejection fraction from baseline to a value < 50%. Lower DASI scores correlated with age and use of medications for hypertension, cardiac conditions, diabetes, and hyperlipidemia, but not with whether patients had received trastuzumab. Conclusion In patients without underlying cardiac disease at baseline, the addition of trastuzumab to adjuvant anthracycline and taxane-based chemotherapy does not result in long-term worsening of cardiac function, cardiac symptoms, or health-related quality of life. The DASI questionnaire may provide a simple and useful tool for monitoring patient-reported changes that reflect cardiac function.

Impact of atezolizumab (atezo) treatment beyond disease progression (TBP) in advanced NSCLC: Results from the randomized phase III OAK study

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Background: Cancer immunotherapy (CIT) can have a positive impact on OS that exceeds response rate or PFS effects, termed post progression prolongation of survival (PPPS). This effect can also result from unconventional CIT response due to tumor immune infiltration or delayed response, reducing reliability of RECIST v1.1 (RECIST) PD as an indicator of treatment failure. In the primary analysis (N = 850) of OAK, a study of atezo vs docetaxel (doc) in 2L/3L NSCLC, OS favored atezo (HR 0.73; 95% CI: 0.62, 0.87), despite similar PFS between arms (HR 0.95; 95% CI: 0.82, 1.10). Here we evaluate clinical benefit from TBP, defined by post PD tumor regression, OS and safety. Methods: Patients (pts) received atezo 1200 mg IV q3w until PD or loss of clinical benefit per investigator or doc 75 mg/m2 IV q3w until PD per RECIST. No crossover was allowed. Primary outcome measure: OS. Atezo TBP pts were evaluated for post PD tumor change and for safety pre and post PD. OS from time of PD per RECIST was evaluated in both arms (data cutoff, July 7, 2016; minimum follow-up, 19 mo). Results: Among 332 atezo pts with PD, 51% (n = 168) continued atezo TBP; 7% (12/168) achieved subsequent response in target lesions (≥ 30% reduction from new baseline at PD); 49% (83/168) had stable target lesions (best change between +20% and −30%). mOS was 12.7 mo (95% CI: 9.3, 14.9) post PD for pts on atezo TBP (Table). Atezo TBP was not associated with increased safety risk. Conclusions: This is the first report from a Phase III study of CIT in NSCLC to evaluate post PD OS in pts continuing treatment beyond RECIST PD. Atezo TBP was associated with high frequency of stable or decreased target lesions, mOS > 1 year and a tolerable safety profile, all supporting prolonged treatment benefit consistent with PPPS. NCT02008227 Clinical trial information: NCT02008227. [Table: see text]

NCI Breast Cancer Steering Committee Working Group (WG) report on meaningful and appropriate endpoints for clinical trials (CT) in metastatic breast cancer (MBC)

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Background: There is significant heterogeneity in the natural history of MBC. Several recent randomized CT have yielded statistically significant advantages for the experimental arm, but neither led to regulatory approval nor practice change. Formal guidance for industry on CT endpoints provided by the US FDA in 2007 was not disease-specific. Patient-focused drug development is mandated by Prescription Drug User Fee Act V. Our WG sought to create specific consensus on endpoints for MBC CT focusing on subtype and line of therapy, with sensitivity to various stakeholders. Methods: A WG composed of medical oncologists, statisticians, advocates, FDA and NCI liaisons performed a systematic literature review of MBC natural history, CT endpoints by subtype (HR+/HER2-, HR+/HER+, HR-/HER2-, HR-/HER2+), and line of therapy (n = 146 papers). External expertise was obtained on industry perspectives, big data and real world evidence (RWE), and patient reported outcomes (PROs). WG members voted anonymously on statements and positions generated from deliberation. Results: The WG reached consensus on definitions relevant to contemporary CT endpoints. WG recommendations on the appropriate choice of OS or PFS are sensitive to expected post progression survival (PPS), and proportional and absolute gains. Currently, for HR-/HER2- MBC, OS is preferred as the optimal primary endpoint regardless of line of therapy; PFS is preferred in settings where expected PPS is longer. Toxicity can outweigh modest gains in PFS; scant data exist to gauge how patients value PFS gain vs toxicity. Where new agents may prolong PFS without impacting OS, exploring/validating graphic approaches that capture grade and timing of toxicity and PROs is warranted. An overview of WG Consensus Statements will be presented in detail. Conclusions: CT design for MBC should be sensitive to natural history (PPS), availability of other effective agents, PROs and toxicity burden. As unique subtypes (e.g. AR+) and novel therapies (e.g. immunotherapy) emerge, reassessment of relevant benchmarks is indicated. Rigorous big data approaches providing insights from RWE may inform CT endpoints in the future.

Two-year trends of taxane-induced neuropathy in women enrolled in a randomized trial of acetyl-l-carnitine (SWOG S0715)

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Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and disabling side effect of taxanes that leads to suboptimal treatment and adversely affects quality of life. Acetyl-L-Carnitine (ALC) was unexpectedly found to increase CIPN in a randomized trial. We investigated the long-term patterns of CIPN among patients enrolled in this trial. Methods: S0715 was a randomized, double-blind, multi-center trial comparing ALC (1000 mg TID) versus placebo for 24 weeks in women with stage I-III breast cancer undergoing taxane-based chemotherapy. The primary objective was to determine if ALC prevents CIPN as measured by the 11-item neurotoxicity (NTX) component of the FACT-Taxane scale at 12 weeks. Additional assessments were conducted at weeks 24, 36, 52 and 104. We examined the reduction of NTX score over 2 years using linear mixed models for longitudinal data, adjusting for stratification factors and the baseline NTX score. Individual assessment time-points were examined using linear regression. Results: SWOG S0715 registered 437 patients, of whom 409 were eligible and evaluable, including 208 assigned to receive ALC and 201 to placebo. Patterns of evaluability were similar over time by arm. The results for the primary outcome of interest, NTX, show a statistically significant (p = 0.01) average difference of -1.39 (95% CI: -2.47 to -0.31) between treatment groups, with the ALC group having lower scores (worse CIPN) on average than the placebo group. These differences were particularly evident at Weeks 24 (p = 0.02), 36 (p = 0.04), and 52 (p = 0.02). A clinically meaningful (≥5 points) reduction in NTX score over baseline was observed more frequently for the ALC vs. control arm (week 24, 41% vs. 34%; week 36, 41% vs. 28%; 1 year, 41% vs. 32%; 2 years, 40% vs. 34%). For both treatment groups 2 year NTX scores were significantly different compared to baseline (p < 0.001). Conclusions: For both groups NTX scores were reduced with taxane-therapy and remained persistently low 2-years following treatment. Twenty-four weeks of ALC therapy resulted in significantly worse CIPN at weeks 24 36 and 52. Understanding the mechanism of this persistent effect may inform prevention and treatment strategies. Clinical trial information: NCT00775645.

Anthracyclines in Early Breast Cancer: The ABC Trials-USOR 06-090, NSABP B-46-I/USOR 07132, and NSABP B-49 (NRG Oncology)

Purpose Docetaxel and cyclophosphamide (TC) was superior to doxorubicin and cyclophosphamide (AC) in a trial in early breast cancer. However, activity of TC relative to AC regimens with a taxane (TaxAC) is unknown. Methods In a series of three adjuvant trials, women were randomly assigned to TC for six cycles (TC6) or to a standard TaxAC regimen. US Oncology Research (USOR) 06-090 compared TC6 with docetaxel, doxorubicin, and cyclophosphamide (TAC6). National Surgical Adjuvant Breast and Bowel Project (NSABP) B-46-I/USOR 07132 compared TC6, TAC6, or TC6 plus bevacizumab. NSABP B-49 compared TC6 with several standard AC and taxane combination regimens. Before any analysis of individual trials, a joint efficacy analysis of TC versus the TaxAC regimens was planned, with invasive disease-free survival (IDFS) as the primary end point. Patients who received TC6 plus bevacizumab on NSABP B-46-I/USOR 07132 were not included. A hazard ratio (HR) from a stratified Cox model that exceeded 1.18 for TC6 versus TaxAC was predefined as inferiority for TC6. The prespecified interim monitoring plan was to report for futility if the HR was > 1.18 when 334 IDFS events were observed (50% of 668 events required for definitive analysis). Results A total of 2,125 patients were randomly assigned to receive TC6 regimens and 2,117 patients were randomly assigned to receive TaxAC regimens. The median follow-up time was 3.3 years. There were 334 IDFS events, and the HR for TC6 versus TaxAC was 1.202 (95% CI, 0.97 to 1.49), which triggered early reporting for futility. The 4-year IDFS was 88.2% for TC6 and was 90.7% for TaxAC ( P = .04). Tests for treatment interaction by protocol, hormone receptor status, and nodal status were negative. Conclusion The TaxAC regimens improved IDFS in patients with high-risk human epidermal growth factor receptor 2-negative breast cancer compared with the TC6 regimen.