Muscle Invasive Bladder Cancer

This phase II trial compares the use of pembrolizumab and radiation therapy to chemotherapy with cisplatin, gemcitabine, 5-fluorouracil or mitomycin-C and radiation therapy for the treatment of non-muscle invasive bladder cancer. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Chemotherapy drugs, such as cisplatin, gemcitabine, 5-fluorouracil or mitomycin-C, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Radiation therapy uses high energy x-rays, particles, or radioactive seeds to kill cancer cells and shrink tumors. Giving pembrolizumab with radiation may kill more tumor cells than chemotherapy with radiation therapy in patients with non-muscle invasive bladder cancer.

This phase II trial tests the effect of giving pembrolizumab in combination with radiation therapy after chemotherapy in preventing surgery to remove the bladder in patients with muscle invasive bladder cancer. Standard of care therapy includes chemotherapy before surgery (neoadjuvant) to shrink or get rid of the tumor. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the tumor, and may interfere with the ability of tumor cells to grow and spread. Radiation therapy uses high energy x-rays, particles, or radioactive seeds to kill cancer cells and shrink tumors. Photon beam radiation therapy is a type of radiation therapy that uses x-rays or gamma rays that come from a special machine called a linear accelerator. The radiation dose is delivered at the surface of the body and goes into the tumor and through the body. Giving pembrolizumab in combination with radiation therapy after neoadjuvant chemotherapy may help prevent surgical removal of the bladder in patients with muscle invasive bladder cancer.

The goal of this clinical trial is to learn whether a combination of two chemotherapy drugs, Gemcitabine and Docetaxel, can treat high-grade non-muscle-invasive bladder cancer (HG-NMIBC) in adults whose cancer failed conventional BCG therapy. The drugs are given directly into the bladder (intravesically), one immediately after the other.

The study will also assess the safety of this treatment.

The main questions it aims to answer are:

Can this drug combination effectively treat HG-NMIBC that did not respond to BCG and help prevent the cancer from coming back, offering long-term protection? What side effects or medical issues do participants experience during treatment?

Researchers will evaluate this non-surgical approach as a potential alternative to bladder removal surgery (radical cystectomy), with the goal of validating it as a bladder-sparing option in this setting.

Participants will:

* Go through a screening process, including tumor removal and imaging tests
* Receive weekly bladder treatments with Gemcitabine followed by Docetaxel for 6 weeks
* If the cancer responds, continue with similar once monthly treatments (maintenance therapy) for up to 2 years
* Attend regular check-ups, including bladder exams, urine tests, biopsies, and optional quality-of-life surveys
* Possibly receive a second 6-week treatment cycle if the cancer returns early
* Be followed for up to 5 years to monitor long-term outcomes

This phase III trial compares the effect of decreased number of radiation (ultra-hypofractionated) treatments to the usual radiation number of treatments (hypofractionation) with standard of care chemotherapy, with cisplatin, gemcitabine or mitomycin and 5-fluorouracil for the treatment of patients with muscle invasive bladder cancer. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a short period of time. Ultra-hypofractionated radiation therapy delivers radiation over an even shorter period of time than hypofractionated radiation therapy. Cisplatin is in a class of medications known as platinum-containing compounds. It works by killing, stopping or slowing the growth of tumor cells. Gemcitabine is a chemotherapy drug that blocks the cells from making DNA and may kill tumor cells. Chemotherapy drugs, such as mitomycin-C and 5-fluorouracil (5-FU), work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving ultra-hypofractionated radiation may be equally effective as hypofractionated therapy for patients with muscle invasive bladder cancer.