A rituximab biosimilar in diffuse large B-cell lymphoma (DLBCL) passes the real-world test with flying colors, according to Manfred Weslau, MD.
A high overall response rate (ORR) of 88% marked results for the first real-world clinical trial of biosimilar rituximab in combination with chemotherapy in patients with CD20-positive diffuse large B-cell lymphoma (DLBCL), confirming the expected efficacy and safety profile of the agent, according to lead author Manfred Welslau, MD.
The biosimilar chosen for the trial was a Sandoz product, marketed in the European Union under the names Riximyo and Rixathon. It is not currently approved or available in the United States. Welslau discussed the trial in an OncLive® interview.
The biosimilar was evaluated in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). “We don’t see any difference between the rituximab biosimilar and the reference product,” Welslau said.
In Europe, rituximab and trastuzumab biosimilars are used about 80% of the time versus 20% for the originators, Welslau said.
“We decided to do this trial even though the biosimilar was already approved in Germany,” he said. “The rituximab biosimilar was already approved because of the significant improvement in follicular lymphoma, and there was extrapolation to all the other indications of reference rituximab, even in rheumatic diseases.”
However, clinicians wanted more information about the equivalency of the Sandoz biosimilar to the reference product in DLBCL, Welslau said.
“We didn't have any clinical data on biosimilars in combination with CHOP in patients with DLBCL. We decided to conduct a trial in over 30 centers in Germany using the rituximab biosimilar instead of reference rituximab. We examined the efficacy and toxicity of the therapy.”
Interim results were presented at the 2020 ASCO Virtual Scientific Program. The ORR was comprised of a 57% complete response and a 31% partial response. Efficacy data were incomplete and the progression-free survival (PFS) data have not yet been reported. Overall, 38% of patients completed the first 12-month observation period, while 41% were continuing treatment and 21% discontinued due to progressive disease.
Adverse events leading to discontinuation of the therapy were observed in 8% of patients. Those included anemia, neutropenia, and fatigue and were the same as for the originator product.
Investigators are still awaiting 24-month PFS data. “In DLBCL, the 24-month PFS is strongly correlated with OS. We should see a good signal for the efficacy of the rituximab [biosimilar] in this patient population.
However, “the take-home message is that you can use the rituximab biosimilar safely and effectively in the treatment of patients with DLBCL,” Welslau said.
In the United States there are 2 rituximab biosimilars on the market: Truxima (Celltrion/Teva) and Ruxience (Pfizer). More competition is anticipated. Amgen and AbbVie (formerly Allergan) in December 2019 filed a Biologics License Application for ABP 798.
Welslau M, Walter N, Otremba BJ, et al. REFLECT real-world evidence prospective study update: efficacy and safety results of Sandoz biosimilar rituximab for the treatment of diffuse large B-cell lymphoma. J Clin Oncol. 2020;38(suppl 15):8060. doi: 10.1200/JCO.2020.38.15_suppl.8060