Andersson, Michael

Abstract Background monarchE is a phase 3, open-label study evaluating abemaciclib combined with endocrine therapy (ET) compared to ET alone in patients with node positive, HR+, HER2-, high risk early breast cancer (EBC) that resulted in a statistically significant improvement in invasive disease-free survival (IDFS) at a pre-planned interim analysis. Following the positive interim analysis, patients continued to be followed for IDFS, distant recurrence, and overall survival. Methods After surgery and, as indicated, radiotherapy and/or chemotherapy, 5,637 patients with HR+, HER2-, high risk EBC were randomized (1:1) to standard of care adjuvant ET with or without abemaciclib (150 mg BD for 2 years). Patients with ≥4 positive nodes, or 1-3 nodes and either grade 3 disease, tumor size ≥5 cm, or central Ki-67 ≥20% were eligible. Here we present results of the primary outcome IDFS analysis which was planned after approximately 390 IDFS events. Results At the primary outcome analysis, median follow-up was approximately 19 months in both arms (an increase of 3.5 months from the interim analysis). A total of 1437 (25.5%) patients had completed the 2-year treatment period; 3281 (58.2%) were still in the 2-year treatment period. With 395 IDFS events observed in the intent-to-treat population, abemaciclib plus ET continued to demonstrate superior IDFS versus ET alone, with a 28.7% reduction in the risk of developing invasive disease (p=.0009; HR = 0.713; 95% CI = 0.583, 0.871). Two-year IDFS rates were 92.3% in the abemaciclib plus ET arm and 89.3% in the ET alone arm. There was a consistent benefit of abemaciclib in all prespecified subgroups. The addition of abemaciclib to ET also resulted in an improvement in distant relapse-free survival (DRFS). Overall survival was immature at the time of analysis. A key secondary endpoint was efficacy in patients with centrally assessed high Ki-67 (≥20%) (Ki-67H) (n=2498). Disease characteristics were well balanced between the arms of this population. Abemaciclib plus ET demonstrated superior IDFS vs ET alone, with a 30.9% reduction in risk of developing invasive disease (p=.0111; HR = 0.691; 95% CI = 0.519, 0.920) and 2-year IDFS rates of 91.6% and 87.1%, respectively. An improvement in DRFS treatment effect was also observed in the Ki-67H population. At the time of data cutoff, the median treatment duration of abemaciclib was 17.3 months and the median duration of ET was balanced between the arms (18.3 months in the abemaciclib arm and 18.7 months in the ET alone arm). Safety was consistent with the results at the interim IDFS analysis and with the known safety profile of abemaciclib. Conclusions At the primary outcome analysis, with a median follow-up of approximately 19 months, abemaciclib combined with ET continued to demonstrate a clinically meaningful improvement in IDFS in patients with HR+, HER2-, node-positive, high risk, EBC with a statistically significant improvement in IDFS in patients with central Ki-67 ≥20%. ClinicalTrials.gov: NCT03155997 Table 1: PrimaryOutcome EfficacyIntent-to-Treat PopulationIntent-to-Treat PopulationKi-67 ≥20% (Ki-67H) PopulationKi-67 ≥20% (Ki-67H) PopulationEndpointAbemaciclib + ET N=2808ET alone N=2829Abemaciclib + ET N=1262ET alone N=1236IDFS# events, n (%)163 (5.8)232 (8.2)82 (6.5)115 (9.3)log rank P value, HR (95% CI)p=.0009 0.713 (0.583, 0.871)p=.0111 0.691 (0.519, 0.920)Rate (%) at 2 years (95% CI)92.3 (90.9, 93.5)89.3 (87.7, 90.7)91.6 (89.4, 93.4)87.1 (84.3, 89.5)Difference (%) in 2-year rates (95% CI)3 (1.1, 5.0)4.5 (1.2, 7.7)DRFS# events, n (%)131 (4.7)193 (6.8)65 (5.2)102 (8.3)log rank P value, HR (95% CI)p=.0009 0.687 (0.551, 0.858)0.609 (0.445, 0.833)Rate (%) at 2 years (95% CI)93.8 (92.6, 94.9)90.8 (89.3, 92.1)93.6 (91.6, 95.1)88.5 (85.7, 90.7)Difference (%) in 2-year rates (95%CI)3 (1.2, 4.8)5.1 (2.1, 8.1) Citation Format: Joyce A. O'Shaughnessy, Stephen Johnston, Nadia Harbeck, Masakazu Toi, Young-Hyuck Im, Mattea Reinisch, Zhimin Shao, Pirkko Liisa Kellokumpu Lehtinen, Chiun-Sheng Huang, Alexey Tryakin, Matthew Goetz, Hope S Rugo, Elzbieta Senkus, Laura Testa, Michael Andersson, Kenji Tamura, Guenther G. Steger, Lucia Del Mastro, Joanne Cox, Tammy Forrester, Sarah Sherwood, Xuelin Li, Ran Wei, Miguel Martin, Priya Rastogi. Primary outcome analysis of invasive disease-free survival for monarchE: abemaciclib combined with adjuvant endocrine therapy for high risk early breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS1-01.

TPS653 Background: Pertuzumab (P) is a humanized monoclonal antibody directed against the dimerization domain of HER2: it prevents HER2 heterodimerization and thus activation of downstream signaling. Since P targets a different epitope than trastuzumab (H), a more comprehensive HER2 blockade is achieved by combining the two agents. Data from CLEOPATRA showed improved efficacy for P and H plus docetaxel. The combination of P and H has not yet been assessed with other chemotherapy partners in the metastatic setting. H plus vinorelbine (V) has shown comparable efficacy to H plus docetaxel but with a superior safety profile. VELVET will assess the overall response rate (ORR) of P with H+V in first-line patients (pts) with HER2-positive MBC. Co-administration of P and H within the same infusion bag will also be investigated as this could increase pt convenience by reducing administration and observation time. Methods: VELVET is a multicenter, open-label, two-cohort, Phase II trial. Pts with HER2-positive LABC or MBC not previously treated in the metastatic setting with non-hormonal anticancer therapy are eligible. Pts must have an LVEF >55% at baseline and an ECOG PS of 0 or 1. Study enrollment started in January 2012. A total of 210 pts will be included. Based on statistical assumptions, 95 pts must be evaluable per cohort, which assumes a withdrawal rate around 10%. Pts in Cohort 1 (the first 105 pts enrolled) will receive P and H sequentially and pts in Cohort 2 (the next 105 pts) will receive P and H in the same infusion bag at Cycle 2 onwards if drug administration in Cycle 1 was well tolerated. V will be given in both cohorts. Treatment duration is until disease progression or unacceptable toxicity. Study dose: P: 840 mg loading dose, 420 mg q3w (iv); H: 8 mg/kg loading dose, 6 mg/kg q3w (iv), and V: 25 mg/m2 Day 1 and 8 (first cycle) then 30−35 mg/m2 Day 1 and 8 q3w (iv) (dose escalation at investigator’s discretion). The primary endpoint is ORR by independent assessment. Secondary endpoints include investigator assessment of ORR, time to response, duration of response, PFS, time to progression, overall survival, safety and tolerability, and QoL.

Abstract Background VELVET Cohort 1 demonstrated the applicability of pertuzumab, trastuzumab, and vinorelbine as an alternative first-line treatment regimen for patients with HER2-positive locally advanced or metastatic breast cancer (MBC) who cannot receive docetaxel. Co-infusion of pertuzumab and trastuzumab may reduce clinic time and medical resource utilization. We report results from Cohort 2, in which pertuzumab and trastuzumab were co-infused, followed by vinorelbine. Patients and Methods During cycle 1, patients with HER2-positive locally advanced or MBC received loading doses of pertuzumab (840 mg) and trastuzumab (8 mg/kg) on consecutive days, followed by vinorelbine (25 mg/m2) on days two and nine. From cycle 2 onwards, patients received a co-infusion of pertuzumab (420 mg) and trastuzumab (6 mg/kg) on day one, followed by vinorelbine (30–35 mg/m2) on days one and eight (or days two and nine). The primary endpoint was objective response rate (ORR) in patients with measurable disease. Secondary endpoints included progression-free survival (PFS) and safety. Results Cohort 2 enrolled 107 patients. The ORR was 63.7% (95% confidence interval [CI] 53.0–73.6) in patients with measurable disease (91/107; 85.0%). Median PFS was 11.5 months (95% CI 10.3–15.8). The most common adverse events [AEs] were diarrhea (57.9%), neutropenia (57.0%), and nausea (41.1%). Grade ≥3 AEs occurred in 85 patients (79.4%) and serious AEs in 44 patients (41.1%). Eighteen patients (16.8%) had AEs suggestive of congestive heart failure. Conclusion These results support the feasibility of pertuzumab and trastuzumab co-infusion from a safety perspective and support Cohort 1 conclusions that vinorelbine offers an alternative chemotherapy companion for pertuzumab and trastuzumab. The Oncologist 2017;22:1160–1168