Background: The anti-PD-1 treatment has been shown good response in patients with cancer. There is little information in open sources on the possibility of changing anti-PD-1 drugs during treatment for non-medical indications. Prolgolimab (formerly BCD-100) is an IgG1 anti–PD-1 mAb that contains the Fc-silencing mutation LALA, which provides an immunopotential advantage by eliminating the interaction between the Fc region of the antibody and FcyR expressed on various immune cells, thus blocking possible effector functions of the antibody. We report the replacement of anti-PD-1 drugs during treatment on safety and anti-PD-1 response in patients with melanoma and lung cancer. Methods: 5 patients with advanced melanoma and 2 non small cell lung cancer (NSCLC) with RECIST-evaluable disease, with prior anti-PD-1 treatment by nivolumab and pembrolizumab. 5 Patients were with prior anti-PD-1 treatment by nivolumab (median duration of treatment was 4 months) and 2 patients pembrolizumab (median duration of treatment was 7 months). Patients were treated (replaced) with prolgolimab (anti-PD-1) 1 mg/kg every 2 week. The primary objective was safety of replacement anti-PD-1 therapy and objective response rate (ORR) by RECIST 1.1. Replacement of anti-PD-1 drugs during treatment were associated for non-medical indications. Patients were with ECOG 0-1. Results: Median age was 57 years, 5 were male, 1 patients with NSCLC had a KRAS mutation and patients with melanoma had a BRAF mutation. Median follow-up was 10 months. Adverse events continued after prescription of prolgolimab. New adverse events have not experienced. Anti-PD-1 therapy was not discontinued. ORR was 85%, of which 3 were CR. Median PFS was not reached. 1 patient with NSCLC prior anti-PD-1 treatment by nivolumab (2 cycles 480 mg) had PD, but PR was prolgolimab. Conclusions: Anti-PD-1 treatment followed by prolgolimab (anti-PD-1) in our patients undergoing therapy is safe and does not worsen anti-tumor responses. We assume that in certain situations it is possible to make (for example, individual intolerance) substitutions of drugs in the same group anti-PD-1 Replacement anti-PD-1 may reduce financial toxicity.