By Alice Park
March 6, 2015

On March 5, a novel way to treat lung cancer won approval from the Food and Drug Administration (FDA). The latest drug, Opdivo, has showed promise with other cancers, and is the first to use the immune system to tackle hard-to-treat lung tumors. Here’s what you need to know.

How does the drug work?

Opdivo (nivolumab), made by Bristol-Myers Squibb, works the same way that releasing a parking brake frees a car to move. Normally, the immune system is held back from recognizing tumors as foreign and potentially harmful, since tumors are the body’s own cells that grow abnormally. Without such checks, “the immune system will destroy you,” says Dr. James Allison, chair of immunology at MD Anderson Cancer Center who discovered the first such brake that protected cancer cells from the immune system. But nivolumab releases this check on the immune system’s normally voracious appetite for anything it doesn’t recognize, so the body’s own defenses can preferentially recognize tumor cells as targets.

In the study submitted by the company to the FDA, 15% of patients showed some shrinkage or complete disappearance of their tumors.

MORE On the Horizon at Last, Cancer Drugs that Harness the Body’s Own Immune System

What makes this drug different from other cancer treatments?

Unlike surgery, chemotherapy, radiation or the anti-cancer drugs that interrupt specific signals that tumor cells use to survive, nivolumab doesn’t target the tumor itself. Rather it focuses on the environment in which the tumor lives, unleashing the immune system so it can recognize cancer cells more easily. “This drug doesn’t treat cancer; it doesn’t kill cancer cells so you can’t inject it and expect cancer to melt away immediately because it won’t,” says Allison. But when it’s combined with tumor-targeted treatments, what it could do is lower the risk of recurrent cancers by training the body’s T cells to recognize specific features of tumors, just as they do for viruses and bacteria, so the immune system can be alerted more quickly and efficiently to dispatch any returning or remaining cancer.

MORE A Shot at Cancer

Other drugs that work in different ways to unleash the immune system have also been approved by the FDA and more are in development.

How will this drug change lung cancer treatment?

While this drug was approved in 2011 to treat melanoma, the expanded approval to include non-small-cell lung cancer, the most common type of lung cancer, now means more patients can take advantage of the new, immune-based strategy to fight their disease. It also opens the door for other, next-generation immune therapies for treating the disease, which many experts thought would not be possible, given how aggressively lung cancer progresses. Now lung cancer patients who have failed other therapies and have no other treatment options have another shot at containing their tumors.

MORE Self-Sabotage: Why Cancer Vaccines Don’t Work

Read next: This Is What It’s Like To Be Awake During Brain Surgery

Listen to the most important stories of the day.

Contact us at editors@time.com.

SPONSORED FINANCIAL CONTENT

Read More From TIME

EDIT POST