Study: Biosimilar Rituximab Increased Access, Survival in DLBCL in India

In patients with diffuse large B-cell lymphoma (DLBCL), rituximab is typically administered with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy for 4 to 6 cycles in early stages and 6 to 8 cycles in advanced stages. While the branded rituximab has been available as MabThera in India since 2002, it was too expensive for widespread use. In 2007, a biosimilar (marketed as Reditux) came to market in India, but there have been few data published on the efficacy of this biosimilar in treating Indian patients with DLBCL.

A recent study, published in the Indian Journal of Cancer, reports outcomes of young patients (n = 444), aged 15 to 60 years, treated between 2000 and 2013 in a tertiary cancer center that serves primarily lower-socioeconomic status patients who received rituximab therapy in conjunction with CHOP.

All patients received CHOP, with rituximab (n = 119) or without rituximab (n = 325). Prior to the availability of the biosimilar, only patients who could afford reference rituximab via private insurance or out-of-pocket had access to the drug. After biosimilar market entry, most patients receiving rituximab were given the biosimilar. From the first year of the study to the last year, the proportion of patients receiving rituximab with CHOP increased from no patients to nearly three-quarters of all patients.

In those who received rituximab with their chemotherapy versus those who received CHOP alone, complete response rate was improved (83.8% versus 73.7%; P = .024). Among patients who received rituximab, 5-year overall survival was 81%, versus 64% for those who received CHOP alone (P = .040).

According to the authors, these findings are key to helping to understand the efficacy of the biosimilar; in India, biosimilars are sometimes approved for use without a large phase 3 efficacy trial to compare a biosimilar to its reference. In the case of this rituximab biosimilar, approval was based on a single-arm study in patients with DLBCL.

“Although these results are not a substitute for randomized phase 3 trials, these can increase confidence among physicians using the biosimilar molecule when it is not possible (due to economic considerations) to use the innovator product,” say the authors, noting that more than 90% of patients with DLBCL treated from 2014 to 2015 had access to rituximab due to the biosimilar’s availability.

Reference

Ganesan P, Sagar TG, Kannan K, et al. Long-term outcome of diffuse large B-cell lymphoma: Impact of biosimilar rituximab and radiation. Indian J Cancer. 2017;54:430-5. doi: 10.4103/ijc.IJC_241_17.