Double-blind, randomized, parallel group, phase III study to demonstrate equivalent efficacy and comparable safety of CT-P6 and trastuzumab, both in combination with paclitaxel, in patients with metastatic breast cancer (MBC) as first-line treatment.

Breast Cancer - HER2/ER
Session Type and Session Title: 
General Poster Session, Breast Cancer - HER2/ER
Abstract Number: 
J Clin Oncol 31, 2013 (suppl; abstr 629)
Young-Hyuck Im, Petro Odarchenko, Daniela Grecea, Dmitry Komov, Chernobay Valentynovych Anatoliy, Sudeep Gupta, Yaroslav V. Shparyk, Priscilla B. Caguioa, Anatoly Makhson, Dmitriy Krasnozhon, Rubi Khaw Li, Dzmitry Noryk, Yurii Oleksiiovych Vinnyk, Gia Nemsadze, Ho Ung Kim, Sang-Joon Lee; Division of Hematology and Medical Oncology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; Vinnitsa National Medical University, Regional Oncological Center, Vinnitsa, Ukraine, Vinnitsa, Ukraine; Cancer Institute I Chiricuta, Napoca, Romania; Russian Oncology Research Center; N.N. Blokhin Cancer Research Center, Moscow, Russia; Poltava Regional Clinical Oncological Center, Poltava, Ukraine; Tata Memorial Centre, Mumbai, India; Lviv Cancer Center, Lviv, Ukraine; University of Santotomas Hospital, Manila, Philippines; Moscow City Oncology Hospital #62, Moscow, Russia; State Medical Institution Leningrad Regional Oncology Center, Leningrad, Russia; St. Luke's Medical Center, Quezon City, Philippines; Grodno Regional Clinical Hospital, Grondo, Belarus; Kharkiv Regional Clinical Oncology Center, Kharkiv, Ukraine; Mammological Center Named After K.Madichi, Tbilisi, Georgia; Celltrion Inc, Incheon, South Korea; Celltrion Inc., Incheon, South Korea

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Abstract Disclosures


Background: CT-P6(C) is an anti-HER2 MoAb, a biosimilar to trastuzumab (T). This trial is a global phase III study to compare C with T, both in combination with paclitaxel (P) as first-line treatment in women with HER2+ MBC. Methods: 475 patients with centrally confirmed HER2+ MBC were randomized to receive either C+P (n=244) or T+P (n=231). Patients had to have a baseline LVEF ≥50% and no history of serious cardiac disease. Study medication was as follows: C or T 8 mg/kg i.v. (day 1), followed by 3-weekly C or T 6 mg/kg. P (175 mg/m23-weekly) was co-administered. The primary endpoint was overall response rate (ORR) as determined by independent review. Pooled analysis with data from phase I/IIb (NCT01084863) and III studies (NCT01084876) was predefined and endorsed by the EMA. Patient safety was monitored throughout the study by an independent data monitoring committee. Treatment was continued until disease progression, death or patient’s withdrawal. Results: In the pooled ITT population, ORR was 57% for C+P and 62% for T+P (difference: 5%; 95% CI: -0.14, 0.04) during the first 8 cycles of treatment. The limits of the 95% CIs for the difference in the proportions of responders were contained within the pre-defined range [-0.15, 0.15] required for equivalence. Median time to progression and median time to response were 11.07 vs. 12.52 months (P =0.10), and 1.38 vs. 1.38 months (P =0.37) for C+P and T+P, respectively. Frequency of treatment-related AEs is shown in the Table. Conclusions: Equivalence of C and T was observed for ORR in patients with HER2+ MBC in combination with P as first-line therapy. Secondary efficacy endpoints also supported the comparability between C and T. C was well tolerated with a safety profile comparable to that of T. Clinical trial information: NCT01084876.

C + P
T + P
Serious AEs 33 (13.5%) 28 (12.1%) 61 (12.8%)
All AEs# 87 (35.7%) 95 (41.1%) 182 (38.3%)
Infusion reaction/hypersensitivity# 38 (15.6%) 60 (26.0%) 98 (20.6%)
Cardiotoxicity# 8 (3.3%) 10 (4.3%) 18 (3.8%)
Infection# 3 (1.2%) 0 (0.0%) 3 (0.6%)

# Treatment related with C or T.