Final overall survival analysis of the phase 3 HERITAGE study demonstrates equivalence of trastuzumab-dkst to trastuzumab in HER2-positive metastatic breast cancer.

PURPOSE: The phase 3 HERITAGE trial demonstrated that the biosimilar trastuzumab-dkst is well tolerated with similar efficacy (measured by overall response rate [ORR] and progression-free survival [PFS]) compared with originator trastuzumab combined with taxane followed by monotherapy in patients with HER2-positive metastatic breast cancer (MBC). Herein, we present final overall survival (OS) from HERITAGE. METHODS: HERITAGE is a multicenter, double-blind, randomized, parallel-group study. Patients were randomized 1:1 to receive trastuzumab-dkst or trastuzumab plus taxane followed by continued monotherapy until disease progression. Overall survival was to be assessed at 36 months or after 240 deaths, whichever occurred first, as observed from time of randomization of last patient. RESULTS: At the final analysis (36 months), 242 patients in the intention-to-treat population had died during the study: 116 and 124 in the trastuzumab-dkst and trastuzumab groups, respectively, and 1 untreated patient from each treatment group. Median OS by Kaplan-Meier analysis was 35.0 months with trastuzumab-dkst and 30.2 months with trastuzumab. Evaluation of PFS showed a median of 11.1 months in both treatment groups. No new safety concerns were reported from week 48 until the end of the survival follow-up. CONCLUSION: This is the first phase 3 trial of a trastuzumab biosimilar to report long-term survival data similar to originator trastuzumab in patients with MBC. The comparable long-term OS between the trastuzumab-dkst and originator trastuzumab groups further supports the similarity of trastuzumab-dkst with originator trastuzumab and establishes trastuzumab-dkst as a safe and effective treatment option for patients with HER2-positive MBC. ClinicalTrials.gov NCT02472964; 6/16/2015.

Effect of a Proposed Trastuzumab Biosimilar Compared With Trastuzumab on Overall Response Rate in Patients With ERBB2 (HER2)-Positive Metastatic Breast Cancer: A Randomized Clinical Trial.

Importance: Treatment with the anti-ERBB2 humanized monoclonal antibody trastuzumab and chemotherapy significantly improves outcome in patients with ERBB2 (HER2)-positive metastatic breast cancer; a clinically effective biosimilar may help increase access to this therapy. Objective: To compare the overall response rate and assess the safety of a proposed trastuzumab biosimilar plus a taxane or trastuzumab plus a taxane in patients without prior treatment for ERBB2-positive metastatic breast cancer. Design, Setting, and Participants: Multicenter, double-blind, randomized, parallel-group, phase 3 equivalence study in patients with metastatic breast cancer. From December 2012 to August 2015, 500 patients were randomized 1:1 to receive a proposed biosimilar or trastuzumab plus a taxane. Chemotherapy was administered for at least 24 weeks followed by antibody alone until unacceptable toxic effects or disease progression occurred. Interventions: Proposed biosimilar (n = 230) or trastuzumab (n = 228) with a taxane. Main Outcomes and Measures: The primary outcome was week 24 overall response rate (ORR) defined as complete or partial response. Equivalence boundaries were 0.81 to 1.24 with a 90% CI for ORR ratio (proposed biosimilar/trastuzumab) and -15% to 15% with a 95% CI for ORR difference. Secondary outcome measures included time to tumor progression, progression-free and overall survival at week 48, and adverse events. Results: Among 500 women randomized, the intention-to-treat population included 458 women (mean [SD] age, 53.6 [11.11] years) and the safety population included 493 women. The ORR was 69.6% (95% CI, 63.62%-75.51%) for the proposed biosimilar vs 64.0% (95% CI, 57.81%-70.26%) for trastuzumab. The ORR ratio (1.09; 90% CI, 0.974-1.211) and ORR difference (5.53; 95% CI, -3.08 to 14.04) were within the equivalence boundaries. At week 48, there was no statistically significant difference with the proposed biosimilar vs trastuzumab for time to tumor progression (41.3% vs 43.0%; -1.7%; 95% CI, -11.1% to 6.9%), progression-free survival (44.3% vs 44.7%; -0.4%; 95% CI, -9.4% to 8.7%), or overall survival (89.1% vs 85.1%; 4.0%; 95% CI, -2.1% to 10.3%). In the proposed biosimilar and trastuzumab groups, 239 (98.6%) and 233 (94.7%) had at least 1 adverse event, the most common including neutropenia (57.5% vs 53.3%), peripheral neuropathy (23.1% vs 24.8%), and diarrhea (20.6% vs 20.7%). Conclusions and Relevance: Among women with ERBB2-positive metastatic breast cancer receiving taxanes, the use of a proposed trastuzumab biosimilar compared with trastuzumab resulted in an equivalent overall response rate at 24 weeks. Further study is needed to assess safety and long-term clinical outcome. Trial Registration: clinicaltrials.gov Identifier: NCT02472964; EudraCT Identifier: 2011-001965-42.

Efficacy, Safety, Pharmacokinetics, and Immunogenicity of DRL-Trastuzumab Versus Herceptin in Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer: A Randomized Controlled Trial.

PURPOSE: Dr Reddy's Laboratories Trastuzumab (DRL_TZ) is a biosimilar to Herceptin under development. The present study was conducted to evaluate efficacy, safety, pharmacokinetics (PKs), and immunogenicity of DRL_TZ in comparison with the reference medicinal product (RMP) along with concomitant weekly paclitaxel in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). METHODS: This was a randomized, double-blind study in female patients with HER2-positive MBC, randomly assigned in a 1:1 ratio to receive either DRL_TZ or the RMP, that is, an innovator product sourced from the European region, along with additional chemotherapy, as first-line treatment for up to 24 weeks. The primary end point was the best overall response rate (ORR) as per RECIST 1.1 criteria. Progression-free survival rate at 6 months (PFS6), safety, immunogenicity, and PK parameters were assessed as secondary end points. RESULTS: A total of 164 patients were randomly assigned to receive either DRL_TZ or the RMP. Best ORR in the per-protocol population was comparable, 91.9% (93.3% CI, 83.2 to 96.3) versus 82.1% (93.3% CI, 72.0 to 89.1) in DRL_TZ and RMP arms, respectively; the difference between the arms was 9.8% with a 93.3% CI of -1.3 to 20.8. The PFS6 rate, safety, PK profile, and antidrug antibody incidence were comparable. An additional 44 patients were recruited in the postrandomization phase, in an open-label manner, and started on DRL_TZ to generate more data on efficacy, safety, and immunogenicity. The additional data with DRL_TZ, when pooled, were similar to the RMP data. CONCLUSION: DRL_TZ was found to have similar efficacy and comparable safety, PK, and immunogenicity profiles as the RMP.

Fixed dose combination of capecitabine and cyclophosphamide in metastatic breast cancer: Results from THE ENCLOSE phase 2/3 randomized multicenter study.

AIM: To evaluate pharmacokinetics, efficacy and safety of fixed-dose combination (FDC) of oral capecitabine + cyclophosphamide in metastatic breast cancer (MBC) patients progressing after anthracycline and/or taxane chemotherapy. METHODS: In this prospective, adaptive, phase-2/3, open-label study (CTRI/2014/12/005234), patients were randomized (1:1:1) to three FDC doses (doses/day: D1, capecitabine + cyclophosphamide 1400 mg + 60 mg; D2, 1800 mg + 80 mg; D3, 2200 mg + 100 mg) for 14 days, in 21-day cycles. In Part-I, multiple-dose pharmacokinetics and optimal dose(s) were evaluated with futility analysis. Group(s) with <3 responders based on best overall response rate (BOR, complete response [CR]+partial response [PR]), were discontinued. Efficacy (BOR, disease control rates [DCR; CR + PR + stable disease]) and safety of optimal dose(s) were evaluated in Part-II. RESULTS: Of 66 patients (n = 22/group) in Part-I, pharmacokinetics (D1 = 7/22, D2 = 9/22, D3 = 8/22) showed dose-proportionality for cyclophosphamide and greater than dose-proportionality for capecitabine. Modified intent-to-treat (mITT) analysis showed BOR of 7.14% (1/14) in D1 (discontinued), and 22.22% (4/18) each in D2 and D3, respectively. In Part-II, 50 additional patients were randomized in D2 and D3 (n = 144; total 72 [22 + 50] patients/group). mITT analysis in D2 (n = 54) and D3 (n = 58) showed BOR of 29.63% (16/54, 95%CI: 17.45-41.81%) and 22.41% (13/58, 95%CI: 11.68-33.15%), respectively. DCR in D2 and D3 were 87.04% (47/54, 95%CI: 78.08-96.00%) and 82.76% (48/58; 95%CI: 73.04-92.48%) after 3 and 57.41% (31/54; 95%CI: 52.41-79.50%) and 50.00% (29/58; 95%CI: 40.40-67.00%), after 6-cycles, respectively. Hand-foot syndrome (16.67%), vomiting (9.72%) in D2, and hand-foot syndrome (18.06%), asthenia (15.28%) in D3 were most-common adverse events. CONCLUSION: FDC of capecitabine + cyclophosphamide (1800 + 80 mg/day) showed high disease control rates and good safety profile in MBC patients.