What Is Jemperli and How Does It Work?
The FDA has approved Jemperli (dostarlimab) for adults with a certain kind of rectal cancer. This approval is for stage II or stage III rectal cancer that has grown into nearby tissues but has not spread to other parts of the body (locally advanced rectal cancer). Although this medicine was already approved for other types of cancer, this is its first approval for rectal cancer.
This approval is only for tumors with special genetic traits. These traits are called mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H). A special lab test checks the tumor for these traits. In tumors with dMMR or MSI-H, cancer cells have trouble repairing mistakes in their DNA. This results in the buildup of abnormal proteins that the body’s immune system can recognize.
Jemperli is a type of medicine known as immunotherapy. It works by blocking a protein called PD-1. Cancer cells often use PD-1 to hide from your body’s natural defenses. By blocking this protein, Jemperli helps your immune system find and fight cancer cells.
Standard treatment for this type of cancer often includes radiation, chemotherapy, and major surgery. For some patients, Jemperli may provide an option to treat their tumor without these invasive procedures.
Why Was Jemperli Approved?
The FDA approved Jemperli based on results from a clinical trial called AZUR-1. The study included 154 adults with previously untreated stage II or stage III dMMR or MSI-H rectal cancer. This study was a single-arm trial. This means every patient in the trial received Jemperli, and there was no comparison group receiving standard chemotherapy or a placebo.
Researchers looked at whether patients’ cancer disappeared completely and stayed gone for at least one year. Of all evaluable patients (119 patients), 47% had no signs of cancer for at least 12 months. Researchers also tracked whether patients needed any other forms of treatment for their cancer. Out of 154 patients, 71% did not need surgery, radiation, or chemotherapy, and their cancer had not advanced or relapsed.
About 20% of patients experienced serious side effects, and 3% stopped treatment due to side effects. The most common side effects included tiredness, skin rash, diarrhea, and itchy skin.
Jemperli was given “accelerated approval”, which means the medicine was approved early because early results were very promising. The drugmaker will continue to study this medicine to confirm its long-term benefits.
What Do I Need to Know?
A healthcare provider gives Jemperli through a needle into a vein (IV). Each infusion takes about 30 minutes and is given once every three weeks for up to nine treatments. Your healthcare provider will decide how many treatments you need.
The most common side effects of Jemperli in patients with this rectal cancer are feeling tired, rash, diarrhea, and itchy skin. Your healthcare provider will order regular blood tests before and during treatment to check your liver, kidneys, and blood counts.
Jemperli works by triggering your immune system. Sometimes, your immune system can attack healthy tissues and organs in your body. These reactions can affect your lungs, intestines, liver, hormone glands, or kidneys and can happen during treatment or months after you finish treatment. Tell your healthcare provider right away if you develop a new cough, chest pain, shortness of breath, severe diarrhea, dark stools, yellow skin or eyes, or severe headaches.
Jemperli can harm a fetus. If you can become pregnant, take a pregnancy test before starting treatment. Make sure to use effective birth control during treatment and for four months after your last dose. It is also important not to breastfeed during treatment and for four months after the last dose. Be sure to tell your healthcare provider about all prescription drugs, over-the-counter medicines, vitamins, and herbal supplements you take.