Jelmyto® (a mitomycin gel) is a medication used to treat low-grade upper tract urothelial carcinoma (UTUC), a rare form of cancer that occurs in the upper urinary tract and affects around 6,000 to 8,000 people in the United States every year.

People with low-grade UTUC may have blood in their urine and/or side pain. While low-grade UTUC typically is not fast-moving, it can progress to a more aggressive cancer, invading nearby tissues and spreading to distant parts of the body.

Treatments are available for low-grade UTUC, including surgery that involves the removal of one side of the upper urinary tract, including the kidney. Another treatment, known as laser ablation, is less invasive and destroys cancerous tumors in the upper urinary tract, but after treatment, the cancer may return, requiring repeated treatments and surveillance.

Jelmyto is a kidney-sparing treatment for low-grade UTUC that received U.S. Food and Drug Administration (FDA) approval in 2020.

Jelmyto is an FDA-approved medication used to treat low-grade upper tract urothelial carcinoma (UTUC). It contains mitomycin, a chemotherapy drug used to treat some types of cancer, and a special gel product that is a liquid at cold temperatures and a gel at body temperature.

Jelmyto is injected as a chilled liquid directly into the upper urinary tract where the cancer is located. When it warms to body temperature, the liquid becomes a gel. The gel remains in the upper tract for four to six hours, meaning that the mitomycin in the medication remains in contact with the tissues—including any cancerous tumors—of the upper urinary tract for a prolonged period. About four to six hours after treatment, the gel is cleared from the body in the urine.

Cancer occurs when cells grow and multiply uncontrollably. Over time, the new cells can form a solid mass of tissue known as a tumor and can invade nearby tissues and spread to distant parts of the body. Mitomycin, the chemotherapeutic agent in Jelmyto, damages the DNA of cancer cells, preventing them from multiplying. This kind of treatment is sometimes called chemoablation because it uses chemicals to ablate—or destroy—cancer cells.

UTUC is a cancer of the urinary tract, the system that eliminates urine from the body. The urinary tract comprises two kidneys, two ureters (tubes that connect the kidneys to the bladder), a bladder, and a urethra. Urine formation begins in the kidneys, then passes through the ureters to the bladder, then through the urethra and out of the body.

UTUC begins in the upper urinary tract, which is made up of the ureters, the renal pelvis (the central region of the kidney where urine collects), and the calyces (cup-like structures that transport urine into the renal pelvis). More specifically, it begins in urothelial cells that line the urinary tract.

UTUC most commonly occurs in people in their 70s and 80s, with an average age at diagnosis of 73 years. It is about three times more common in men than women. UTUCs can be either low grade, meaning they are less aggressive and slower growing, or high grade, meaning they are more aggressive and grow faster.

Several treatments are available for low-grade UTUC, including:

• Radical nephroureterectomy (RNU), a surgical procedure in which the entire kidney, ureter, and bladder cuff (where the ureter connects to the bladder) are removed. While RNU is an effective treatment (though cancer sometimes recurs in the bladder after RNU), it can cause short-term complications and lead to problems in the functioning of the remaining kidney.
• Laser or electrocautery ablation, minimally invasive procedures in which a doctor inserts a ureteroscope—a long, thin tube equipped with a camera, light, and tools for procedures—into the upper urinary tract and then destroys tumors using a laser or electrical current. These treatments allow patients to keep their kidney and ureter intact; however, sometimes not all of the cancer is removed or the cancer recurs, requiring additional surveillance and treatment.
• Segmental ureterectomy is the surgical removal of part of the ureter. It may be an option if the cancer occurs in only one part of the ureter.

Jelmyto provides patients and their doctors with an additional kidney-sparing, minimally invasive treatment option for low-grade UTUC. Unlike systemic chemotherapy, in which the anticancer medication travels through the blood to reach all parts of the body, with Jelmyto, the chemotherapy is applied directly to the upper urinary tract where the cancer is located.

Before the procedure, patients typically take three doses of sodium bicarbonate. Sodium bicarbonate raises the pH (reduces the acidity) of urine, which helps mitomycin work better and may also reduce the recurrence of tumors. These are usually taken orally the evening before, the morning of, and 30 minutes prior to the procedure. Before the procedure, you may be given general anesthesia, local anesthesia, and/or sedation during the procedure so that you do not feel any pain.

Your health care provider will prepare the Jelmyto prior to administration. The medication will be chilled so that it is a liquid. The provider will then inject the Jelmyto directly into the upper urinary tract (the affected kidney and ureter) via a catheter—a thin plastic tube—inserted through the urethra and bladder and into the ureter, or through a nephrostomy tube (a catheter inserted through the skin of the back and into the kidney).

Administration of Jelmyto is an outpatient procedure, so you can go home the same day. Treatment usually involves weekly doses for six weeks. If you have a good response to Jelmyto, your health care provider may continue to administer an additional dose of Jelmyto once a month for up to 11 months.

People should talk with their provider about the following health conditions/medications before or during a Jelmyto treatment:

• Bladder/upper tract perforation. Tell your health care provider if you have a history of bladder or upper tract perforation. Jelmyto shouldn’t be used to treat patients with this issue.
• Pregnancy. Jelmyto can cause harm to an unborn baby. A pregnancy test may be required before beginning treatment with Jelmyto. Women should not become pregnant during treatment. Those who become pregnant while being treated with Jelmyto should inform their health care provider immediately. Individuals who can become pregnant should use contraception during treatment and for six months after receiving their last dose. Men undergoing Jelmyto treatment should use contraception during treatment and for three months after their last dose if they have a partner who can become pregnant. While it is unknown whether Jelmyto is present in breast milk, breastfeeding should be avoided during treatment and for one week after the last dose.
• Diuretics. People who take diuretics—water pills—should inform their doctor before treatment. The use of diuretics may need to be discontinued the day before getting a Jelmyto dose and for four hours after treatment.

After treatment with Jelmyto, the urine contains active mitomycin, a chemotherapy medication. Because of this, for about six hours after treatment, people need to follow certain precautions when they urinate, including:

• Avoiding contact with urine for at least six hours after receiving a dose of Jelmyto
• Sitting on a toilet to urinate and flushing the toilet several times afterward
• Washing hands, inner thighs, and genital area after going to the bathroom
• Separating any clothing that comes into contact with urine from other clothing and washing it immediately

People who use Jelmyto may experience side effects, including:

• Narrowing or swelling of the ureter (symptoms may include side pain and fever; people with these symptoms should contact their doctor immediately)
• Urinary tract infection (UTI)
• Blood in urine
• Nausea
• Pain or discomfort during urination
• Kidney dysfunction
• Vomiting
• Abdominal pain
• Hydronephrosis (swelling of a kidney that usually occurs due to a blockage of urine flow out of the kidney)
• Fatigue
• Anemia
• Back pain
• Frequent urination
• Itching
• Chills
• Decreased appetite

In rare cases, Jelmyto may cause bone marrow suppression, resulting in reduced white blood cell, red blood cell, and platelet counts. People may also develop neutropenia (abnormally low white blood cell levels) and/or thrombocytopenia (low levels of platelets). Your provider will order regular blood tests to monitor your blood count during treatment. If neutropenia or thrombocytopenia are severe enough, treatment with Jelmyto may be discontinued.

Jelmyto is the first therapy to receive approval from the FDA for the treatment of low-grade UTUC. In a clinical trial, participants with low-grade UTUC were given six once-weekly doses of Jelmyto and then assessed for the presence of tumors in the upper urinary tract three months after their first dose. In the trial, 58% of participants had no tumors three months after starting their treatment, and of these participants, 56% were tumor-free after 12 months.

This article was reviewed by Yale Medicine urologist Joseph Brito III, MD.