Rituximab Biosimilar Equivalent to Reference Rituximab in Treating Advanced Follicular Lymphoma
By Jenny Powers
MADRID, Spain -- September 14, 2017 -- Treatment with a rituximab biosimilar (GP2013) plus cyclophosphamide, vincristine, prednisone (CVP) has an overall response rate (ORR) equivalent to rituximab-CVP in patients with previously untreated, advanced-stage follicular lymphoma, according to results of the phase 3 ASSIST-FL trial reported at the 42nd European Society for Medical Oncology (ESMO) Congress.
“GP2013 represents an important option that may help to decrease the cost of cancer care, making it sustainable for patients who benefit from rituximab,” stated lead author Wojciech Jurczak, MD, PhD, Jagiellonian University Kraków, Kraków, Poland, speaking here on September 10.
In the ASSIST-FL trial, Dr. Jurczak and colleagues compared GP2013-CVP to rituximab-CVP in terms of efficacy, safety, pharmacokinetics and pharmacodynamics in patients with previously untreated, advanced-stage follicular lymphoma. The primary efficacy endpoint was equivalence in ORR defined by a 95% confidence interval [CI] with a margin of ±12% standard deviation.
The investigators randomised 629 patients equally to 8 cycles of either GP2013-CVP or rituximab-CVP, followed by monotherapy maintenance for up to 2 years in responders. A total of 314 patients received the biosimilar, while 315 received rituximab-based treatment.
Patients had a median follow-up of 23.8 months until data cut-off on December 31, 2016. The primary endpoint of ORR was 87.1% with GP2013 compared with 87.5% with rituximab, demonstrating a difference of -0.40% (95% CI: -5.94% to 5.14%).
Median PFS and OS for GP2013 versus rituximab have not been reached; however, the PFS and OS rates were comparable at 69.9% versus 75.9% (hazard ratio [HR] 1.31; 90% CI: 1.02 to 1.69) and 92.6% versus 90.8% (HR 0.77; 90% CI: 0.49 to 1.22), respectively.
Similarity between the 2 drugs was also demonstrated for pharmacokinetics, pharmacodynamics, safety, and immunogenicity. The pharmacokinetics and pharmacodynamics profiles demonstrated a ratio of geometric means of 1.00 (90% CI: 0.925 to 1.09) for peak serum concentration at cycle 4 day 1 and 0.939 (90% CI: 0.845 to 1.04) for area under the effect curve to the last observation at 21 days (AUEC0–21d) of peripheral B-cells.
“In June 2017, the European Commission approved GP2013 for use in all indications of the reference medicine,” Dr. Jurczak noted.
Rituximab is a monoclonal immunoglobulin G-1 antibody targeting the CD20 antigen on B cells. The rituximab biosimilar, GP2013, was developed according to biosimilar development guidelines, and has previously demonstrated equivalence in rheumatoid arthritis in a clinical trial.
Funding for this study was provided by Hexal AG, Holzkirchen, Germany.
[Presentation title: Equivalent Efficacy of a Biosimilar Rituximab and Reference Rituximab in Previously Untreated Advanced Follicular Lymphoma: Extended Results of ASSIST-FL, a Confirmatory Phase III Study. Abstract 994O]