A Clinical Study of the Pharmacokinetics and Safety of BCD-263 and Opdivo® as Monotherapy in Subjects With Advanced Melanoma of the Skin

Inclusion Criteria:

1. Age ≥18 years at the time of signing the informed consent form;
2. Body weight 60 to 90 kg.
3. Histologically confirmed melanoma with the following prognostic characteristics:

   * LDH \<ULN of local laboratory (enrollment of subjects with LDH \<2x ULN of local laboratory is allowed until the number of subjects with LDH \>ULN is 30% of the total population of randomized subjects. The Sponsor will inform when enrollment of subjects is limited by LDH level \<ULN of the local laboratory).
   * Absence, according to the Investigator, of clinically significant symptoms associated with the tumor.
   * Absence, according to the Investigator, of rapidly progressing metastatic melanoma.
4. Newly diagnosed advanced unresectable (stage III) or metastatic disease (stage IV), or progressive disease during / relapsing after radical treatment.

Exclusion Criteria:

1. Indications for radical treatment (surgery, radiation therapy).
2. Uveal or mucosal melanoma.
3. Previous systemic anticancer therapy for advanced unresectable or metastatic skin melanoma (a history of neoadjuvant or adjuvant therapy is allowed, provided that the therapy was completed at least 12 weeks before randomization).
4. Active CNS metastases and/or carcinomatous meningitis.
5. Previous invasive cancer, excluding diseases treated with potentially curative therapy with no evidence of recurrence for 2 years from the start of this therapy (subjects with radically resected basal cell carcinoma of the skin, superficial bladder cancer, squamous cell carcinoma of the skin, cervical carcinoma in situ of the uterus and other carcinomas in situ may be included).
6. Subjects with severe concomitant disorders, life-threatening acute complications of the primary disease (including massive pleural, pericardial, or peritoneal effusions requiring intervention, pulmonary lymphangitis, bleeding or organ perforation) at the time of signing the informed consent and during the screening period.
7. Concomitant diseases and/or conditions that significantly increase the risk of adverse events (AEs) during the study.