AstraZeneca and Merck score as Lynparza nabs first-ever nod to treat BRCA breast cancer

Lynparza, developed by AstraZeneca and now shared with Merck & Co., won an approval in breast cancer ahead of its PARP inhibitor rivals, Clovis Oncology's Rubraca and Tesaro's Zejula. (AstraZeneca)

AstraZeneca's first-in-class ovarian cancer drug Lynparza just won a coveted approval to treat BRCA-mutated breast cancer. It's the first therapy specifically greenlighted for that type of cancer, the FDA said, and the first new field for the hot new class of oncology meds known as PARP inhibitors.

It was a quick go-ahead from the FDA, which granted Lynparza priority review for the new indication just three months ago, and Lynparza's phase 3 details only hit in June at the American Society of Clinical Oncology meeting. And it's not just a boon for AstraZeneca, but for Merck & Co., which inked an $8.5 billion deal with the U.K.-based drugmaker in July to share Lynparza and study the med in combination with its own immunotherapy, Keytruda, as well as AstraZeneca's fellow PD-1, Imfinzi.

This new approval could make BRCA testing as routine for breast cancer patients as current screenings for HER2 and hormone receptor status are, AstraZeneca EVP Dave Fredrickson, who heads up the company's oncology unit, said in a statement.

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Indeed, AstraZeneca sees Lynparza's advent in breast cancer to be as practice-changing as it was in ovarian cancer. Michelle Werner, who headed up AstraZeneca’s U.S. oncology business at the time, told FiercePharma at ASCO that “[t]he ability to have an option that is not chemotherapy is also, I think, tremendous in terms of the potential that it has in being able to have a positive impact on a patient’s quality of life.”

The ASCO-presented study data that underpinned the FDA filing showed Lynparza—previously approved in ovarian cancer and ovarian cancer maintenance—shrank tumors in 60% of the HER2-negative breast cancer patients with BRCA1 or BRCA2 mutations.

RELATED: AstraZeneca, Merck team up on Lynparza combos in collaboration worth up to $8.5B

Importantly, the drug proved effective among patients with triple-negative breast cancer, a notoriously difficult-to-treat form of the disease. Overall, Lynparza cut the risk or death or disease progression—known as progression-free survival—by 42%.

“This class of drugs has been used to treat advanced, BRCA-mutated ovarian cancer and has now shown efficacy in treating certain types of BRCA-mutated breast cancer,” Richard Pazdur, M.D., the FDA's oncology chief, said in a statement. “This approval demonstrates the current paradigm of developing drugs that target the underlying genetic causes of a cancer, often across cancer types.”

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With the new approval, Lynparza will be able to tackle an entirely new market, once again boasting a first-in-class nod. About 155,000 women in the U.S. have metastatic breast cancer, and an estimated 5% carry a germline BRCA mutation, an AZ spokeswoman said. The BRCA-positive group are often younger than typical breast cancer patients.

Clovis Oncology’s Rubraca and Tesaro’s Zejula are both under study as breast cancer treatments; Rubraca is in a combo phase 3 with Bristol-Myers Squibb's immuno-oncology blockbuster Opdivo, according to Clovis' pipeline site. Zejula is in phase 2 with its breast cancer trial, in combination with Merck's rival PD-1 therapy Keytruda.

Now, of course, AZ will have Merck's help in launching Lynparza for the new breast cancer indication. Their deal isn't without its detractors, however; when the news rolled out in July, some analysts said it traded away a long-term, potentially impressive revenue stream in return for short-term gains. Still, Merck will bear a big chunk of the costs of extending Lynparza into other new indications, including a potential combo nod alongside the PD-1 blockbuster Keytruda.

Under their partnership, Friday's approval triggered a $70 million payment from Merck to AZ. Up to $6 billion could follow, depending on future indications and sales. Lynparza is in further testing in prostate cancer and pancreatic cancer.

Editor's note: This story was updated with additional comments from AstraZeneca and a new job role for Michelle Werner.