Prostate-specific membrane antigen (PSMA) is a protein found in small amounts in your prostate gland. When you have prostate cancer, you have many times more PSMA than normal. This makes PSMA a good target for treating advanced prostate cancer. You might hear this new treatment called lutetium PSMA therapy, Lu-PSMA, or just PSMA therapy.
What It Is
Lutetium Lu 177 vipivotide tetraxetan (Pluvicto) treats advanced (metastatic) prostate cancer when the cancer cells have PSMA. It uses two parts joined together. A molecule, vipivotide tetraxetan, finds and attaches to PSMA on cancer cells. A radioactive medicine, lutetium 177 (Lu 177), binds to vipivotide tetraxetan, which carries it into the tumor.
It's injected into a vein and travels through the body, delivering radiation directly to PSMA-positive cancer cells.
This helps destroy cancer with less harm to healthy tissue. PSMA therapy won’t cure prostate cancer, but it may ease symptoms, slow its growth, and help you live longer.
Who Gets It
PSMA therapy is approved for two groups of men with metastatic prostate cancer whose tumors test positive for PSMA. The first is men whose cancer is still responding to hormone therapy — for them, PSMA therapy is given together with a hormone-blocking drug called an ARPI. The second is men whose cancer has stopped responding to hormone therapy after trying an ARPI — for them, PSMA therapy may be used instead of starting chemotherapy, or after chemotherapy has already been tried. In both cases, you'll continue ongoing hormone-suppressing treatment throughout.
Before Treatment
Your doctor will talk with you about possible side effects and answer any questions you have. You'll have tests to make sure PSMA therapy is right for you. These include blood tests and tests to check your kidneys and salivary glands. You’ll also have a PSMA PET scan that can spot cancer outside your prostate. This will help target your treatment.
How You Get It
PSMA therapy usually takes place in a hospital’s nuclear medicine department. A health care professional injects the medicine into a vein in your arm.
It takes about 30 minutes for the drug to infuse into your bloodstream. You may get anti-nausea meds and a diuretic to help flush the Lu 177 from your system. After that, you may need to wait in the hospital for a few hours or longer to make sure your radiation levels start to come down.
Most people have up to six PSMA treatment cycles, one every 6 weeks. Your doctor may check periodically to see if your treatment is working and adjust or stop it based on your response and side effects.
A day or two after your treatment, you may have an imaging test called a single-photon emission computerized tomography (SPECT) scan. This checks to make sure your therapy hits the right targets.
Because the drug is radioactive, you'll also need to take some precautions at home afterward:
- Keep some distance (about 3 feet) from others for a couple of days, and extra distance from children and pregnant women for about a week
- Avoid sexual activity for about a week
- Sleep in a separate room from others for a few days — longer if children or pregnant women are in your household
Your care team will walk you through the exact timeline based on your dose.
Side Effects
PSMA therapy can cause:
Most of these symptoms go away in a few days. There’s a small chance that dry eyes and mouth can be permanent. A few people have lower blood counts because Lu 177 can affect your bone marrow.
PSMA therapy may cause temporary or permanent infertility in men, but this isn't guaranteed, so pregnancy is still possible during treatment. If your partner could become pregnant, your doctor will likely recommend effective contraception during treatment and for about 14 weeks after your last dose, since radiation exposure during this time could harm a developing fetus.
Lu 177 can also target healthy organs that have very small amounts of PSMA, like your salivary glands, small intestine, and kidneys.
Talk with your doctor to see if PSMA treatment is right for you.
