Dostarlimab is a monoclonal antibody that works as an immune checkpoint inhibitor by blocking the programmed death receptor-1 (PD-1) pathway. By targeting PD-1, it restores the body’s immune response against tumour cells, helping the immune system recognise and destroy cancer cells.

The U.S. FDA first approved Dostarlimab in April 2021 under accelerated approval for the treatment of recurrent or advanced mismatch repair-deficient (dMMR) endometrial cancer that progressed on or after platinum-based chemotherapy. It was later granted full approval in February 2023 for the same indication. Dostarlimab is also being studied and approved in various countries, including the European Union and India, for broader use in other solid tumours with dMMR.

Dostarlimab is used in the treatment of:

• Recurrent or advanced dMMR endometrial cancer in adults whose disease has progressed following platinum-based chemotherapy.

• dMMR solid tumours (including colorectal, gastric, and ovarian cancers) that have progressed after prior treatment, in patients with no satisfactory alternative therapies.

• Ongoing clinical studies are exploring its role in combination immunotherapies for other cancers.

The immune system uses checkpoints like PD-1 to prevent overactivation. Cancer cells exploit this by expressing PD-L1, which binds PD-1 and “switches off” immune T-cells.

Dostarlimab blocks PD-1 receptors on immune cells, preventing tumour cells from deactivating them. This restores T-cell activity, allowing the immune system to attack and kill cancer cells.

• Form: Intravenous (IV) infusion.

• Administration: Given by a healthcare professional in a hospital or clinic.

• Dosage:

1. Typically, 500 mg IV every 3 weeks for 4 doses, followed by 1000 mg IV every 6 weeks.

2. Dose adjustments may be needed for toxicity management.

• Not for self-administration, patients are closely monitored during and after infusion for infusion-related reactions.

Common:

• Fatigue

• Nausea, diarrhoea, or constipation

• Rash or itching

• Loss of appetite

• Cough

• Headache

• Abdominal pain

Serious :

• Lung inflammation (pneumonitis) – cough, chest pain, shortness of breath

• Liver problems (hepatitis) – yellowing of eyes/skin, dark urine, severe fatigue

• Colitis – persistent diarrhoea, bloody stools, severe abdominal pain

• Kidney problems (nephritis) – reduced urine, swelling in legs, high blood pressure

• Endocrine disorders – thyroid problems, adrenal insufficiency, diabetes

• Severe infusion reactions – fever, chills, dizziness, difficulty breathing.

• Immune-related side effects can affect multiple organs (lungs, liver, colon, kidneys, endocrine glands).

• May increase the risk of serious infections.

• Pregnancy/Breastfeeding: May harm an unborn baby or infant. Not recommended.

• Requires permanent discontinuation if life-threatening immune reactions occur.

• Contraception: Women should use effective birth control during treatment and for at least 4 months after the last dose.

• Avoid live vaccines, as the immune system may be suppressed.

• Monitoring required: Regular blood tests for liver, kidney, thyroid, and hormone levels.

• Inform your doctor if you have an autoimmune disease, organ transplant history, or prior severe infusion reactions.

• Treatment should only be given in specialised centres with immunotherapy monitoring facilities.

• Report fever, persistent cough, abdominal pain, yellowing of eyes/skin, or severe diarrhoea immediately.

• Blood tests (liver, thyroid, kidney, and blood counts) are required at regular intervals.

• Do not stop treatment without medical guidance.

• Always inform healthcare professionals if you are scheduled for surgery or vaccinations.

1. David O’Malley et al., “Checkpoint inhibition in mismatch repair-deficient tumours: dostarlimab outcomes,” The Lancet Oncology, [2022] https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(22)00299-4/fulltext
   

2. U.S. FDA, “FDA grants accelerated approval to dostarlimab-gxly for dMMR endometrial cancer,” [April 2021] https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-dostarlimab-gxly-dmmr-endometrial-cancer

3. EMA, “Jemperli (dostarlimab): EPAR – Product Information,” [Accessed Sept 2025] https://www.ema.europa.eu/en/medicines/human/EPAR/jemperli

4. Luis A. Diaz Jr. et al., “Mismatch Repair Deficiency and Response to PD-1 Blockade in Colorectal Cancer,” The New England Journal of Medicine, [2022] https://www.nejm.org/doi/full/10.1056/NEJMoa2201445

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.