Retrospective analysis of the safety and efficacy of Pembroria® during non-medical switching from the original drug Keytruda® in patients with advanced malignancies of various localizations in real clinical practice

Introduction. The emergence of genetically engineered biological drugs is rightly considered a revolutionary event in medicine. In 2022, the first biosimilar of pembrolizumab, the Russian drug Pembroria®, was approved. One of the study types that can convincingly demonstrate the safety and efficacy of biosimilar is its use for switching from the original drug for non-medical indications (NMS, or non-medical switching) according to standard approaches of real clinical practice and the drug label.

Aim. To assess the safety of NMS switching in patients with advanced malignancies of various localizations from the original drug Keytruda® to the biosimilar Pembroria® and to evaluate its effectiveness in real clinical practice.

Materials and methods. We analyzed the data of 114 patients with advanced malignancies of various localizations and the last line of treatment with Keytruda® as monotherapy or in combination with other agents within the approved indications and switched to Pembroria® for NMS. After switching to Pemboria®, patients did not change treatment for another checkpoint inhibitor within this line of therapy.

Results. The incidence of immune-mediated adverse reactions (imARs) of any severity during treatment with comparators differed slightly: 57% with Keytruda® and 54% with Pembroria®. The majority of imARs with both Keytruda® and Pembroria® were Grade 1 in severity (69% and 86%, respectively). All serious ARs were resolved and did not result in drug discontinuation. When analyzing the best objective response to treatment with Keytruda®, complete response, partial response, and stabilization were observed in 9 (7.9%), 28 (24.6%), and 61 (53.5%) cases, respectively, during treatment with Pemboria® – in 8 (7%), 24 (21%), 52 (45.6%) cases, respectively.

Conclusion. The safety profile of Keytruda® and Pembroria® is acceptable and comparable: the imAR rate with Pembroria® when switching from Keytrada® did not exceed that with the original drug Keytruda®; in most patients, switching from Keytruda® to Pembroria® was not associated with an increase in the imAR rate or severity. The majority of patients maintained disease control when switched to Pembroria®.