The US Food and Drug Administration (FDA) approved a groundbreaking new drug for the most common form of pancreatic cancer, offering US patients a more effective treatment against one of the deadliest types of the disease.

FDA officials gave expedited approval to the first-of-a-kind pill, called daraxonrasib, that blocks a mutated protein which fuels tumor growth in more than 90% of pancreatic cancer cases. It’s an approach that has eluded drugmakers for decades.

The daily pills will be sold by Revolution Medicines under the brand name Rasonque.

Patients taking the drug nearly doubled their survival time, with fewer severe side effects, in a study that randomly assigned them to receive the experimental treatment or more chemotherapy. The company-funded study enrolled 500 patients whose metastatic, or spreading, cancer had stopped responding to prior treatment.

Patients getting the new treatment lived for a median of 13.2 months compared with 6.7 months for chemotherapy recipients.

Pancreatic cancer is among the most deadly forms in large part because it is hard to detect before it starts spreading to other organs. The American Cancer Society estimates about 67,000 new cases will be diagnosed in the United States this year and more than 52,000 people will die from the disease. The five-year overall survival rate is 13%.

The drug garnered public attention earlier this year when former US senator Ben Sasse of Nebraska described on CBS’s 60 Minutes program how he has had less pain while taking it. A surge in public interest led the FDA to allow “expanded access”, before the drug’s official approval, for patients who met certain criteria.

FDA regulators noted on Wednesday that they approved the drug more than six months ahead of their target date.

“It is our fundamental duty to deliver more cures and meaningful treatments to patients as quickly as possible,” the FDA’s acting commissioner, Kyle Diamantas, said in a statement.

Doctors who treat pancreatic cancer have expressed optimism that approval of the drug may usher in more new options, with dozens of experimental drugs in development. Unlike with other cancers that have benefited from a variety of chemotherapy alternatives, pancreatic cancer has been harder to tackle.

The new drug targets mutations in the Ras gene family that normally regulates cell growth. What are known as Kras mutations are especially critical in fueling pancreatic cancer. But a structure that made it hard for drugs to stick to the mutated proteins meant this cancer driver was long considered “undruggable”.

Revolution Medicines’ drug uses what’s essentially a molecular glue to bind with multiple Kras subtypes. The drugmaker, based in Redwood City, California, is studying its technology with other forms of cancer, including lung cancer.