Jemperli (Dostarlimab): What It Is and What to Expect

This page is for people offered dostarlimab (Jemperli) and their families. It covers how it works, what it is approved for, side effects, and when to call for help.

Jemperli is the brand name. Dostarlimab is the generic name. It blocks PD-1, a receptor on T cells (a type of immune cell). Tumors press on PD-1 to switch the immune response off. With PD-1 blocked, the T cell keeps going.

A tumor test drives most of its use. Cancers that are mismatch repair deficient, written dMMR, have lost the machinery that corrects DNA copying errors. They pile up mutations, which makes them look strange to the immune system, and that is what this class of drug exploits. Ask whether your tumor was tested for dMMR, and what the result was.

The label has two parts.

For womb cancer, dostarlimab is approved with carboplatin and paclitaxel, then continued alone, for adults with primary advanced or recurrent disease. This use does not require a dMMR result. It is also approved alone for dMMR womb cancer that has grown during or after platinum chemotherapy, when surgery or radiation cannot cure it.

The second part is unusual. Dostarlimab is approved for any dMMR solid tumor that has come back or advanced despite earlier treatment, when there is no good alternative. Where the cancer started does not matter. The test result does.

That second use, called tumor-agnostic because it is based on the test result rather than where the cancer started, holds accelerated approval. The FDA granted it based on how many tumors shrank. The label says continued approval may depend on confirmatory trials.

This is not a warning that the drug does not work. It is a statement about how much is known, and it is fair to ask your oncologist what the evidence looks like for a cancer like yours.

When used alone, the most common side effects on the FDA label are tiredness or weakness, anemia, diarrhea and nausea. With chemotherapy, the list is longer and includes nerve damage, hair loss and low blood counts.

The more serious pattern is the immune system turning on healthy tissue. The label describes reactions that can be severe or fatal, in the lungs, bowel, liver, hormone glands, kidneys, skin and elsewhere. They can appear at any point, including after treatment ends. Your team may treat them with steroids.

For womb cancer with chemotherapy, it is given by infusion every 3 weeks for 6 cycles. After that the infusions move to every 6 weeks at a larger amount, continuing until the cancer grows, until side effects stop it, or for up to 3 years. Each dose runs into a vein over about 30 minutes.

• Call 911 or go to an emergency department if you cannot catch your breath, your chest hurts, or a rash starts blistering or peeling away from the skin. Do not drive yourself.
• Call your care team right away if you have a new or worse cough, diarrhea or severe belly pain, yellow eyes or skin, dark urine, a change in how much you pass urine, an unusual headache, or feel drained and dizzy with unusual thirst.
• Call your care team right away also if a rash is spreading, or you feel colder, heavier or flatter than normal, which can point to a hormone gland.

These reactions can begin months after the last infusion, so raise them even if treatment has finished.

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=095eab9f-545a-4f12-bfb7-19477fb901a5

https://www.cancer.gov/about-cancer/treatment/drugs/dostarlimab-gxly