Adults with a specific form of bladder cancer that does not respond to standard treatment have a new option after the U.S. Food and Drug Administration approved the expanded use of Anktiva, the first treatment specifically approved for patients with BCG-unresponsive, high-grade papillary-only non-muscle invasive bladder cancer (NMIBC).

The treatment, nogapendekin alfa inbakicept-pmln, is given with Bacillus Calmette-Guérin (BCG) and is approved for cancer that has not spread into the bladder’s muscle layer, an agancy news release said. BCG stimulates the immune system inside the bladder, but cancer can persist or return despite treatment. Anktiva provides another way to help the immune system fight the disease.

The expanded approval also marks a new approach by the FDA to evaluating treatments for closely related forms of bladder cancer. The agency relied on evidence from Anktiva’s earlier approval for carcinoma in situ (CIS), with or without papillary tumors, alongside clinical and laboratory evidence showing similarities between CIS and high-grade papillary-only disease.

“We listen to patients, clinicians, and researchers, and we act when the science supports a new approach,” R. Angelo de Claro, M.D., director of the FDA’s Oncology Center of Excellence, said in the release. “For Anktiva, our review of the similarities between these cancers allowed us to build on the results in patients with CIS and expand treatment options for people with high-grade papillary tumors alone. This approach may also help guide the development of future treatments.”

NMIBC has not grown into the bladder’s muscle layer. CIS forms flat patches along the bladder lining, while papillary tumors grow into the bladder as small, finger-like projections. CIS is always high-grade, while papillary tumors can be low-grade or high-grade. High-grade cancers are more likely to grow and spread.

Anktiva’s original approval for CIS was supported by clinical trial NCT03022825, which evaluated 77 adults, some of whom also had papillary tumors. In the trial, 62% achieved a complete response, meaning no high-grade cancer was detected during follow-up. Of those patients, 58% maintained the response for at least 12 months and 40% for at least 24 months.

For the expanded approval, the FDA considered those results alongside evidence that CIS and high-grade papillary tumors often occur together, can be difficult to distinguish under a microscope and carry a high risk of returning or progressing when BCG stops working. The agency used those similarities to apply the effectiveness evidence from patients with CIS to patients with high-grade papillary-only disease.

The FDA is also working to finalize draft guidance titled “Bacillus Calmette-Guérin-Unresponsive Nonmuscle Invasive Bladder Cancer: Developing Drugs and Biological Products for Treatment.” The guidance is intended to explain how studies involving patients with CIS can support approval of treatments for BCG-unresponsive, high-grade papillary-only NMIBC.

Anktiva is administered with BCG directly into the bladder through a catheter once a week for six weeks. Additional treatment depends on the cancer’s response, and treatment may continue for up to 37 months. It should be stopped if cancer persists after a second six-week course, returns or progresses, or side effects become unacceptable.

Common side effects and laboratory abnormalities include painful or frequent urination, urinary urgency, blood in the urine, urinary tract infections, muscle or joint pain, chills, fever and increased blood levels of creatinine and potassium. The prescribing information warns that delaying surgery to remove all or part of the bladder can allow cancer to spread to other parts of the body, potentially resulting in death.

The FDA granted the expanded approval to Altor BioScience LLC.