By Julie Steenhuysen

CHICAGO (Reuters) – AstraZeneca and Merck & Co’s Lynparza helped patients with advanced pancreatic cancer who carry BRCA gene mutations go nearly twice as long without their disease worsening than those who received a placebo, according to data from a late-stage clinical trial presented on Sunday.

BRCA mutations are typically linked with breast and ovarian cancers, but occur in other cancers as well.

Lynparza was tested against a placebo as a maintenance therapy in 154 patients with metastatic pancreatic cancer whose tumors had not progressed after chemotherapy.

Those who received the Merck and AstraZeneca drug on average went 7.4 months before their disease began to worsen, a measure known as progression-free survival (PFS). That compared with a median PFS of 3.8 months for placebo, according to data presented at the American Society of Clinical Oncology meeting in Chicago.

For the 6-7% of pancreatic cancer patients who carry these inherited mutations, the finding is significant.

“This was clearly positive,” said Dr. Eileen O’Reilly, a pancreatic cancer expert at Memorial Sloan Kettering Cancer Center in New York, who helped lead the study.

O’Reilly said the findings reinforce new guidelines from the National Comprehensive Cancer Network recommending universal BRCA testing for all patients with pancreatic cancer.

Mutations in BRCA genes impair the ability to repair DNA damage, which can drive cancer growth. Lynparza and other drugs in the class known as PARP inhibitors keep cancer cells damaged by chemotherapy from repairing themselves. Lynparza became the first PARP drug to reach the market with a U.S. approval for ovarian cancer in late 2014.

“In pancreatic cancer, progress has been really slow so this is really quite exciting data for patients who have the BRCA mutation,” said Dr. Baynes, Merck’s chief medical officer.

An interim analysis, however, showed the drug made no significant difference in overall survival.

“We typically see about 10 to 12 months” for overall survival in these patients, O’Reilly said. Patients in both arms of the Lynparza study lived about 18 to 19 months.

The companies expect results in the second half of the year for Lynparza in prostate cancer patients with BRCA mutations, and have ongoing studies in endometrial and lung cancer.

“We are now talking about a medicine that actually may have the opportunity to improve outcomes for patients across a multitude of cancer types if they are harboring the BRCA mutation,” Dave Fredrickson, AstraZeneca’s global head of oncology, said in an interview.

Lynparza is an important growth driver for AstraZeneca, generating $647 million in sales last year. Analysts have forecast $2.5 billion in revenue from the drug in 2023, according to Refinitiv data. Use in pancreatic cancer in addition to breast and ovarian cancer would boost Lynparza sales and cement its lead over rival PARP inhibitors Rubraca from Clovis Oncology, GSK’s Zejula and Pfizer’s talazoparib.

(Reporting by Julie Steenhuysen; additional reporting by Ludwig Burger in Frankfurt; editing by Bill Berkrot)