AstraZeneca Plc showed that its drug Lynparza slowed progression of a devastating, inherited form of breast cancer that typically strikes younger women, potentially opening up a new market for a pill originally approved to treat ovarian tumors.
A study of 302 women, dubbed OlympiAD, found that those getting the drug were 42 percent less likely to see their cancer spread than those given conventional chemotherapy, according to results presented at the American Society of Clinical Oncology meeting in Chicago. Women taking Lynparza had their disease progress after about seven months, compared with 4.2 months of median progression-free survival for those on chemotherapy.
“This represents a real improvement in the care of women” who have the specific subtype of the disease, said Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. “Not only are the responses better, the quality of life is better as well, which should always be an important part of the conversation.”
Researchers will need more time to show whether those benefits transfer into living longer. The study was funded by AstraZeneca.
Lynparza is one of three new drugs known as PARP inhibitors approved for women with inherited ovarian cancer. Though they represent a big change for patients, they’re a mid-size market to drugmakers: the therapies from AstraZeneca, Tesaro Inc. and Clovis Oncology Inc. may generate a collective $1.2 billion by 2020, according to Bloomberg Intelligence.
AbbVie Inc.’s experimental treatment in the same class failed in April, making the AstraZeneca-funded study the first to show that PARP drugs might also help those with breast cancer driven by the inherited mutations.
“It worked across the board,” said lead author Mark Robson, who is clinic director of the clinical genetics services at Memorial Sloan Kettering Cancer Center in New York. “Everybody we treated seemed to derive a benefit.”
About 60 percent of those given Lynparza responded to the therapy, compared with 29 percent of those treated with conventional chemotherapy. The study, from the final phase of research needed to get a drug approved, was in women whose cancer had spread or come back after initial treatment.
Trial participants all had inherited mutations in the BRCA genes, which predispose women to cancer, and were an average of about 44 years old — younger than typical breast cancer patients. The researchers also found a benefit in so-called triple negative breast cancer, often considered the form that’s hardest to treat because it isn’t fueled by three types of receptors linked to hormones or growth factors that have existing therapies.
AstraZeneca is running a large final-stage trial of Lynparza as the first-line of treatment to keep breast cancer from recurring after surgery and chemotherapy. Also under way are late-stage trials in pancreatic, prostate and first-line ovarian tumors.
The OlympiAD study showed that the drug could help some patients avoid chemotherapy, AstraZeneca Chief Medical Officer Sean Bohen said in a telephone interview.
“It expands us into a different disease,” Bohen said. “It expands us into a different treatment paradigm.”
PARP inhibitors work by hindering a type of protein, called PARP, that’s involved in DNA repair. By disrupting cancer cells’ ability to repair themselves, the drugs are meant to slow uncontrolled growth and replication of cells — the hallmark of cancer. Breast tumors are the most common type of cancer in women, with some 250,000 cases likely to be diagnosed in the U.S. this year, according to the American Cancer Society. About 3 percent of breast cancers are in people who inherited BRCA mutations, according to the OlympiAD researchers.
More research is needed to identify women most likely to respond and determine if those with less common genetic mutations could benefit, Robson said.
“This is the first drug we have targeting an inherited genetic change in breast cancer,” he said, adding that side effects were limited and the drug could be taken at home, resulting in a better quality of life for patients. “It’s going to be a great option.”