Jennifer Matthews: Each year, ovarian cancer claims the lives of more than 15,000 women. Treatment may help initially, but the cancer often comes back.

Dr. Tyler Curiel: These patients are relapsing one or two years later because a very small handful of cells eventually grow back.

Jennifer Matthews: Tulane doctor Tyler Curiel says that relapse is even harder to treat. That's why he's searching for something better.

Dr. Tyler Curiel: What we're trying to do is harness the body's own immune system to let the immune system clear the cancer out.

Jennifer Matthews: Targeting the immune system is not new, but the way Doctor Curiel and his team are doing it is. Instead of giving patients more T-cells -- the fighter immune cells -- they're focused on destroying harmful immune cells.

Dr. Tyler Curiel: It turns out that one of the T-cells in your body, in cancer, is a bad actor. It's like friendly fire. The soldiers, instead of going out and shooting the enemy, they're shooting other soldiers.

Jennifer Matthews: Doctor Curiel hopes a new drug that kills off those bad-acting immune cells will show the same success in humans as it did in the lab.

LeeAnna Guidry has the same hope. She was diagnosed with ovarian cancer two years ago.

LeeAnna Guidry: When you're faced with this illness, you're just kind of hoping for a miracle.

Jennifer Matthews: LeeAnna is one of four patients enrolled in the study so far. Doctor Curiel believes that, if it works, the treatment will extend patients' lives.

LeeAnna Guidry: My hope is for whatever time I can get, I'll take it.

Jennifer Matthews: This is Jennifer Matthews reporting.