Phase 3 results suggest the biosimilar product CT-P10 is equivalent to rituximab in patients with low-tumor-burden follicular lymphoma (FL).
Overall response rates were similar—both exceeding 80%—in patients who received CT-P10 and those who received rituximab.
In addition, adverse event (AE) profiles were comparable between the treatment arms.
Larry W. Kwak, MD, PhD, of City of Hope in Duarte, California, and his colleagues reported these results in The Lancet Haematology.
The phase 3 trial of CT-P10 included 258 patients with stage II-IV low-tumor-burden FL. They were randomized to receive CT-P10 (n=130) or rituximab (n=128).
Patients received intravenous CT-P10 or rituximab weekly for 4 weeks as induction therapy. Patients experiencing disease control went on to a maintenance phase with their assigned treatment, given every 8 weeks for six cycles, followed by another year of maintenance therapy with CT-P10 for those still on study.
The overall response rate at 7 months was 83% in patients randomized to CT-P10 and 81% in those randomized to rituximab.
The complete response rates were 28% and 34%, respectively. The unconfirmed complete response rates were 5% and 2%, respectively. And the partial response rates were 51% and 46%, respectively.
The two treatments were deemed therapeutically equivalent, as the two-sided 90% confidence intervals for the difference in proportion of responders between CT-P10 and rituximab were within the prespecified equivalence margin of 17%.
Treatment-emergent AEs occurred in 71% of patients in the CT-P10 arm and 67% of those in the rituximab arm.
The most common treatment-emergent AEs (in the CT-P10 and rituximab arms, respectively) were:
- Infusion-related reactions (31% and 29%)
- Infections (27% and 21%)
- Worsening neutropenia (22% for both)
- Upper respiratory tract infection (12% and 11%)
- Worsening anemia (10% and 14%)
- Worsening thrombocytopenia (8% and 7%)
- Fatigue (7% and 9%)
- Diarrhea (5% for both)
- Nausea (5% for both)
- Urinary tract infection (4% and 5%)
- Headache (3% and 5%).
Serious AEs were reported in six patients in the CT-P10 arm and three patients in the rituximab arm.
Two serious AEs—myocardial infarction and constipation—in the CT-P10 arm were considered related to treatment. None of the serious AEs in the rituximab arm were considered treatment-related.
Two patients in the CT-P10 arm discontinued treatment due to AEs—one due to myocardial infarction and one due to dermatitis. There were no AE-related discontinuations in the rituximab arm.
There were two deaths in the CT-P10 arm as of the cutoff date (January 4, 2018). One was due to myocardial infarction, and one was due to respiratory failure. The myocardial infarction was considered possibly related to treatment.
This trial was sponsored by Celltrion, the company developing CT-P10. Three study authors are employees of the company.
Dr. Kwak and several other authors not employed by Celltrion reported disclosures related to the company. Authors also reported relationships with Novartis, Roche, AbbVie, Celgene, and Takeda, among other entities.