FDA approves new treatment for advanced bladder cancer

The FDA today approved the first new treatment for metastatic bladder cancer in nearly 30 years. The drug, called atezolizumab, is a type of immunotherapy treatment designed to boost the body's natural defenses against cancer.

Dr. Arjun Balar, an oncologist at NYU Langone Medical Center explained how the medicine works.

"Our immune systems are designed to identify, target, and destroy cancer cells. However, what cancer cells do is they preferentially co-opt off-switches to evade the immune system and basically run rampant and spread throughout the body," he told CBS News.

Atezolizumab -- being marketed by the FDA as TECENTRIQ -- works by giving the body back control of these off-switches to allow it to fight the cancer, he explained.

Bladder cancer is the fourth most common cancer in men in the U.S., though it is less common in women, according to the American Cancer Society. Each year, about 77,000 adults nationwide are diagnosed with the disease, which causes about 16,000 deaths annually.

The majority of bladder cancer patients are over the age of 55. That's why Kevin Williamson -- a father of five living in Chicago -- was shocked when he was diagnosed at age 43.

"It was something I never really thought about," he told CBS News. "My wife and I have always been very healthy. I guess I got it in my head that people got cancer when they're old."

After surgery to get his bladder removed and trying several experimental drugs, Williamson entered a clinical trial using atezolizumab. His tumors shrunk by 40 percent within the first year and have since stabilized. Now, three years after his diagnosis, at 47, Williamson is back to being an active husband and father.

"I feel great. I'm back to working out and being active," he said.

According to a press release on the FDA's website, the safety and efficacy of the atezolizumab were studied in a clinical trial involving 310 patients. The results showed nearly 15 percent of participants experienced at least a partial shrinkage of their tumors. Participants with a higher expression of PD-L1 -- a protein believed to play a major role in suppressing the immune system -- appeared to benefit most, with 26 percent experiencing a tumor response.

While these numbers may not seem very high, Balar explains that they are, in fact, pretty significant.

"The advances over the past three decades [in advanced bladder cancer treatments] have been in patient safety, which means they are more tolerable and we've been better able to manage side effects," he said. "But the efficacy, which means how well the patients do overall in terms of how long they survive from cancer, has not changed in nearly 30 years. So to have a drug like this, which while it does not work in the majority and only works in the minority, it is life-altering for the patients who receive the treatment and benefit from it."

He also notes that atezolizumab is generally well-tolerated with the most common side effects being fatigue, decreased appetite, nausea, urinary tract infection, fever, and constipation.

The FDA approved the drug under its "breakthrough therapy designation" program, which helped expedite its development and review.

"We hope this is just the beginning of a completely new era in bladder cancer therapy," Balar said. "Atezolizumab and similar drugs will serve as the backbone for new immunotherapy drugs as we try to build upon the success we've had so far."