Breast Cancer Drug Granted Priority Review

Abemaciclib is a CDK4/6 inhibitor being explored in advanced breast cancer.

Eli Lilly and Company recently announced that the FDA has accepted the new drug application (NDA) for abemaciclib and has granted the drug priority review designation for the treatment of advanced breast cancer, according to a press release.

The NDA includes a submission for 2 indications: abemaciclib as a monotherapy for patients with hormone-receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer who received prior endocrine therapy and chemotherapy for metastatic cancer; and abemaciclib plus fulvestrant in patients with HR+, HER2- advanced breast cancer whose disease progressed following endocrine therapy, according to the release.

The NDA is based on positive findings from the MONARCH 1 and MONARCH 2 clinical trials.

Abemaciclib is a cyclin-dependent kinase (CDK) 4 and 6 inhibitor. A majority of cancers are the result of decreased cell regulation due to increased signaling from CDK4 and CDK6. Abemaciclib has shown promise blocking cancer cell growth by inhibiting the pathways.

In breast cancer, cyclin D1/CDK4 has been observed to increase phosphorylation of the retinoblastoma protein (Rb), cell proliferation, and tumor growth, according to Lilly. In hormone receptor-positive breast cancer cells, investigators found that abemaciclib lessened the phosphorylation of Rb.

Survival for advanced breast cancer remains low, with 5-year relative survival rates at 26% for patients with metastatic disease, according to the release. These low survival rates underscore the urgent, unmet need of these patients.

In 2015, abemaciclib was granted breakthrough therapy designation based on findings from an expansion of the phase 1 JPBA clinical trial, which explored the safety and efficacy of the drug in patients with advanced or metastatic breast cancer.

Lilly plans to submit abemaciclib to the European regulatory authorities in the third quarter of 2017 and to the Japanese regulatory authorities before the end of the year, according to the release.

Additionally, abemaciclib is being evaluated in a phase 3 clinical trial in patients with lung cancer.

"We are pleased that the FDA has granted abemaciclib Priority Review, both as a potential monotherapy and combination therapy [with fulvestrant] for patients with advanced breast cancer," said Levi Garraway, MD, PhD, senior vice president, global development and medical affairs, Lilly Oncology. "Breast cancer is a complex disease, and the need still exists for new treatment options as patients face a significant disease burden. We look forward to working with the FDA and bringing this important potential treatment option to patients as soon as possible."