Celltrion Inc.

PurposeNeoadjuvant CT-P6, a trastuzumab biosimilar, demonstrated equivalent efficacy to reference trastuzumab in a phase 3 trial of HER2-positive early-stage breast cancer (EBC) (NCT02162667). We report post hoc analyses evaluating pathological complete response (pCR) and breast pCR alongside additional efficacy and safety measures.MethodsFollowing neoadjuvant treatment and surgery, patients received adjuvant CT-P6 or trastuzumab (6 mg/kg) every 3 weeks for ≤ 1 year.ResultsIn total, 271 and 278 patients received CT-P6 and trastuzumab, respectively. pCR and breast pCR rates were comparable between treatment groups regardless of age, region, or clinical stage. Overall, 47.6% (CT-P6) and 52.2% (trastuzumab) of patients experienced study drug-related treatment-emergent adverse events (TEAEs), including 17 patients reporting heart failure (CT-P6: 10; trastuzumab: 7). Two CT-P6 and three trastuzumab patients discontinued adjuvant treatment due to TEAEs.ConclusionAdjuvant CT-P6 demonstrated comparable efficacy and safety to trastuzumab at 1 year in patients with HER2-positive EBC, supporting CT-P6 and trastuzumab comparability.Electronic supplementary materialThe online version of this article (10.1007/s00280-019-03920-4) contains supplementary material, which is available to authorized users.

IMPORTANCEThe drug HD201 is a biosimilar candidate for breast cancer treatment as the reference trastuzumab.OBJECTIVE To compare the efficacy of HD201 with referent trastuzumab.DESIGN, SETTING, AND PARTICIPANTS This randomized clinical trial (TROIKA) included 502 women with ERBB2-positive early breast cancer treated with either HD201 or referent trastuzumab. It was conducted across 70 centers in 12 countries, including Western and Eastern Europe and Asian countries. Randomization was stratified by tumor hormone receptor status, clinical stage, and geographic region of recruitment. This analysis was conducted on February 12, 2021, after the completion of the adjuvant phase at a median of 31 months (IQR, 28-33 months) of follow-up.INTERVENTIONS Patients with ERBB2-positive early breast cancer were randomly assigned to receive HD201 or referent trastuzumab in the neoadjuvant setting for 8 cycles, concurrently with 4 cycles of docetaxel, which was followed by 4 cycles of epirubicin and cyclophosphamide. Patients then underwent surgery, which was followed by treatment with 10 cycles of adjuvant HD201 or referent trastuzumab. MAIN OUTCOME AND MEASURESThe primary end point was the total pathological complete response (tpCR) assessed after neoadjuvant treatment. Equivalence was concluded if the 95% CI of the absolute difference in tpCR between arms in the per-protocol set was within the margin of more or less than 15%. Other objectives included the breast pathological complete response, overall response, event-free and overall survival, safety, pharmacokinetics, and immunogenicity.RESULTS A total of 502 female patients (mean [range] age, 53 [26-82] years) were randomized to receive either HD201 or referent trastuzumab, and 474 (94.2%) were eligible for inclusion in the per-protocol set. The baseline characteristics were well balanced between the 2 arms; 195 tumors (38.8%) were hormone receptor-negative , and 213 patients (42.4%) had clinical stage III disease. The tpCR rates were 45% and 48.7% for HD201 and referent trastuzumab, respectively. The difference between the 2 groups was not significant at −3.8% (95% CI, −12.8% to 5.4%) and fell within the predefined equivalence margins. The ratio of the tpCR rates between the 2 arms was 0.92 (95% CI, 0.76 to 1.12). A total of 433 patients (86.1%) presented with 2232 treatment-emergent adverse events of special interest for trastuzumab during the entire treatment period, with 220 (88.0%) and 213 (84.5%) patients in the HD201 and referent trastuzumab groups, respectively. CONCLUSIONS AND RELEVANCEThe results of this randomized clinical trial found that HD201 demonstrated equivalence to referent trastuzumab in terms of efficacy for the end point of tpCR, with a similar safety profile.

510 Background: CT-P6 (C) is a proposed biosimilar to trastuzumab. This trial (NCT02162667) evaluated the similarity of C and trastuzumab in efficacy and safety for HER2+ EBC. Methods: 549 patients with HER2+ EBC were randomized to receive C (n=271) or trastuzumab (n=278) in combination with docetaxel (Cycles 1-4) and 5-fluorouracil, epirubicin, and cyclophosphamide (Cycles 5-8). C or trastuzumab was administered at 8 mg/kg (Cycle 1 only) followed by 6 mg/kg every 3 weeks. The primary endpoint was pathological complete response (pCR) rate at surgery. Secondary endpoints were overall response rate (ORR), PK, PD and safety. After surgery, patients received adjuvant C or trastuzumab to complete a total of 1-year treatment. Results: The pCR rate was 46.8% for C and 50.4% for trastuzumab. The 95% CIs for the risk ratio estimate were within the equivalence margin (0.74, 1.35) in PPS and ITT analyses. Other efficacy endpoints were similar between C and trastuzumab. The proportion of patients with at least 1 treatment-emergent SAE was 6.6% for C and 7.6% for trastuzumab. Only 1 patient in each group withdrew treatment due to significant LVEF decrease. Infusion-related reaction was reported for 8.5% of patients in C and 9.0% of patients in trastuzumab. Conclusions: This study demonstrated the similarity of efficacy in terms of pCR between CT-P6 and trastuzumab in EBC patients. Secondary efficacy endpoints also supported the similarity between CT-P6 and trastuzumab. CT-P6 was well tolerated with a similar safety profile to that of trastuzumab during the neoadjuvant period. Clinical trial information: NCT02162667. [Table: see text]

Purpose Equivalent efficacy was demonstrated for the biosimilar CT-P6 and trastuzumab following neoadjuvant therapy for patients with human epidermal growth factor receptor-2 (HER2)-positive early breast cancer. Following adjuvant treatment, efficacy and safety were comparable between treatments. We report updated safety and efficacy data after up to 3 years’ follow-up. Methods Following neoadjuvant chemotherapy with CT-P6/trastuzumab, patients underwent surgery and continued receiving adjuvant CT-P6/trastuzumab. The primary endpoint (previously reported) was pathological complete response. Time-to-event analyses (disease-free survival [DFS], progression-free survival [PFS], and overall survival [OS]), study drug-related and cardiac adverse events, and immunogenicity were assessed during post-treatment follow-up. Results Most patients entered the follow-up period (CT-P6: 259 [95.6%]; trastuzumab: 269 [96.8%]). After a median follow-up of 38.7 (CT-P6) and 39.6 (trastuzumab) months, medians were not reached for time-to-event parameters; estimated hazard ratios (HRs) and 3-year survival rates were similar between groups. Estimated HRs (95% confidence intervals) for CT-P6 versus trastuzumab were 1.23 (0.78–1.93) for DFS, 1.31 (0.86–2.01) for PFS, and 1.10 (0.57–2.13) for OS (intention-to-treat population). Safety findings were comparable between groups for the overall study and follow-up period, including study drug-related cardiac disorders (CT-P6: 22 [8.1%] patients; trastuzumab: 24 [8.6%] patients [overall]) and decreases in left ventricular ejection fraction. Immunogenicity was similar between groups. Conclusion The similarity of the time-to-event analyses between CT-P6 and trastuzumab supports the equivalence in terms of efficacy established for the primary endpoint. CT-P6 was well tolerated, with comparable safety and immunogenicity to trastuzumab. ClinicalTrials.gov: NCT02162667 (registered June 13, 2014)