Socazolimab is a prescription immunotherapy used to treat certain types of advanced cancer. This treatment does not directly attack cancer cells but instead enhances the body’s own immune system to recognize and destroy them. This approach represents a continued focus on targeted, immune-based therapies in cancer care.
Mechanism of Action
Socazolimab functions as an immune checkpoint inhibitor, targeting a protein called Programmed Death-Ligand 1 (PD-L1). The PD-1/PD-L1 pathway is a natural system that helps regulate immune responses and prevent the immune system from attacking healthy cells. Some cancer cells exploit this pathway by overexpressing the PD-L1 protein on their surface, which acts as a “do not attack” signal to immune cells called T-cells.
When PD-L1 on a cancer cell binds to PD-1 on a T-cell, it deactivates the T-cell, allowing the cancer to hide and grow. Socazolimab works by binding directly to the PD-L1 protein on tumor cells, which blocks this interaction. By preventing this connection, the drug “unmasks” the cancer cells, removing the inhibitory signal and allowing T-cells to recognize and attack the tumor.
This medication also possesses a secondary function known as antibody-dependent cell-mediated cytotoxicity (ADCC). The structure of the socazolimab antibody allows it to attract other immune cells, such as Natural Killer (NK) cells, to the tumor’s location. These NK cells then help destroy the cancer cells, and this dual action is designed to create a more robust immune response against the cancer.
Approved Medical Uses
The primary approved use for socazolimab is in treating recurrent or metastatic cervical cancer. It is intended for patients whose disease has progressed during or after first-line platinum-based chemotherapy, providing a second-line treatment option for individuals with limited alternatives.
Beyond cervical cancer, socazolimab is under investigation for a range of other solid tumors. Clinical trials are exploring its efficacy in extensive-stage small-cell lung cancer (ES-SCLC) as a first-line treatment combined with chemotherapy. Further studies are also underway for its use in treating advanced urothelial carcinoma, osteosarcoma, and esophageal cancer, both as a monotherapy and in combination with other treatments.
The Treatment Process
Socazolimab is administered in a clinical setting, such as a hospital or infusion center. The medication is given as an intravenous (IV) infusion, delivered directly into the bloodstream through a vein. The infusion is administered periodically, with a common regimen being once every two or three weeks.
The recommended dose is 5 mg/kg, calculated based on the patient’s body weight, and the infusion is administered over 30 to 60 minutes. Patients may receive socazolimab for up to two years, as long as the treatment remains effective and is tolerated. A physician determines the specific treatment duration based on the cancer type, patient health, and response to the medication, with regular monitoring conducted throughout the course.
Common Side Effects
As an immunotherapy, socazolimab’s side effects are related to its stimulation of the immune system. These are known as immune-related adverse events (irAEs) and occur when the enhanced immune response affects healthy tissues.
Commonly reported side effects are mild to moderate and can include fatigue, skin reactions like rash and itching, and gastrointestinal issues such as diarrhea and nausea. When combined with chemotherapy, a higher incidence of hematologic side effects like anemia, neutropenia, and thrombocytopenia has been observed. These reactions are manageable.
Less frequently, more serious irAEs can occur and require prompt medical attention. These can involve inflammation of organs, leading to conditions like colitis (inflammation of the colon), pneumonitis (inflammation of the lungs), and hepatitis (inflammation of the liver). Patients should report any new or worsening symptoms to their healthcare provider for proper management.
Clinical Efficacy and Approval
For its approved indication in recurrent or metastatic cervical cancer, one study showed an objective response rate (ORR) of 15.4%. The drug showed activity regardless of PD-L1 expression status, with response rates of 16.7% in PD-L1-positive patients and 17.9% in PD-L1-negative patients. The median overall survival (OS) in this study was 14.72 months.
In a phase 3 trial for extensive-stage small-cell lung cancer (ES-SCLC), combining socazolimab with chemotherapy resulted in a median OS of 13.90 months, compared to 11.58 months for chemotherapy plus a placebo. The ORR for the socazolimab group was 75.5%, versus 68.1% for the placebo group.
Based on this evidence, socazolimab received approval from China’s National Medical Products Administration (NMPA) for treating recurrent or metastatic cervical cancer. The Chinese Society of Clinical Oncology (CSCO) also includes it in its 2024 guidelines. Developed by Sorrento Therapeutics and licensed to Lee’s Pharmaceutical for Greater China, its regulatory status with agencies like the U.S. FDA or the EMA is not established.