European patients with non-Hodgkin lymphoma (NHL) are more likely to be prescribed a rituximab (MabThera, EU; Rituxan, US) biosimilar if they are in better overall health, have indolent histology, and have follicular lymphoma, according to a study presented at the 2018 ASCO Annual Meeting.
Further, in the United Kingdom and Germany, the 2 countries with the highest use of rituximab biosimilars, prescription rates for the biosimilars were higher in treatment lines beyond the frontline.
“Physicians who start prescribing rituximab biosimilars seem to adopt a precautionary strategy, initiating the biosimilar in situations where potential side effects would be less debilitating, such as for patients in better overall health, or those associated with a better prognosis,” said lead study author Alessandra Franceschetti, director, Global Oncology Monitors at Ipsos Healthcare, United Kingdom.
The first rituximab biosimilar, Truxima, was approved by the European Medicines Agency (EMA) in February 2017. This was followed by Rixathon and Riximyo in June 2017, and Blitzima, Ritemvia, and Rituzena in July 2017.
The multicenter medical chart study presented at ASCO included prescribing data from 97 physicians who treated patients with NHL. Overall, the study included the medical charts of 640 patients from the EU5 countries of France (n = 117), Germany (n = 73), Italy (n = 117), Spain (n = 136), and the United Kingdom (n = 197). Data were collected from July 2017 to September 2017.
Of the 640 patients, 70% had received a regimen that included rituximab and 7% had been treated with a rituximab biosimilar. The biosimilar prescribing rates were highest in Germany, where 14% of patients received a biosimilar versus standard rituximab in 66%, and the United Kingdom, where 13% of patients were treated with a rituximab biosimilar versus 66% with standard rituximab. The corresponding rates were 0% versus 68%, 3% versus 75%, and 5% versus 76% in France, Italy, and Spain, respectively.
Franceschetti noted that the higher biosimilar prescribing rates in Germany and the United Kingdom may just be a product of the fact that commercialization of the products after EMA approval started first in those 2 countries.
The researchers assessed prescribing patterns by line of treatment among 174 NHL patients in the United Kingdom and Germany who had started their most recent anticancer treatment within 3 months of the physician report. Overall, 73% had received standard rituximab and 14% had received a rituximab biosimilar. Biosimilar use increased with later lines of treatment. Among 110 patients receiving frontline treatment, 81% received standard rituximab and 11% received a biosimilar. The rates were 65% versus 18% among 48 patients in the second-line setting, and 44% versus 30% among 16 patients receiving third-line or higher treatment.
Franceschetti also added that in the United Kingdom and Germany, “Compared to patients treated with a regimen including rituximab branded, those reported as being treated with a rituximab biosimilar are more likely to have an ECOG performance status of 0-1 (93% vs 82%) and not have comorbidities affecting cancer drug treatment (52% vs 31%).”
Regarding histology, patients in the United Kingdom and Germany treated with standard rituximab were almost equally likely to have indolent (52%) or aggressive (48%) disease. However, patients receiving biosimilar rituximab were far more likely to have indolent (70%) over aggressive (30%) disease.
When assessing NHL subtype in these patients, the clear majority of patients treated with a biosimilar had follicular lymphoma (56%), with the next highest groups being marginal zone lymphoma and diffuse large cell lymphoma at 15% each. Among patients receiving standard rituximab, the 2 highest subgroups were diffuse large cell lymphoma with 36% and follicular lymphoma with 35%.
In her concluding remarks, Franceschetti said, “As level of experience increases over time, physicians might start prescribing biosimilars rather than the branded option more frequently, hence, this analysis will be repeated in July–September 2018 and extended to additional indications where other [rituximab] biosimilars have now been employed, but prescribing in the day-to-day clinical practice has not yet taken place.”
Franceschetti A, Caldeira R. Treatment approach for non-Hodgkin lymphoma patients since first biosimilars of rituximab approved in EU5. J Clin Oncol. 2018;36 (suppl; abstr 112).