López-Vega, José Manuel

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