10:05 AM EST, 12/10/2024 (MT Newswires) -- Arvinas ( ARVN ) and Pfizer ( PFE ) on Tuesday reported "encouraging" preliminary data from an ongoing phase 1b trial of their vepdegestrant drug candidate in combination with Eli Lilly's ( LLY ) abemaciclib kinase inhibitor in patients with a form of breast cancer.

Trial results from 16 patients with locally advanced or metastatic estrogen receptor positive and human epidermal growth factor receptor 2 negative breast cancer demonstrated a tolerable safety profile for the combination of 200 milligrams of vepdegestrant daily with 150 milligrams of abemaciclib twice daily.

The drug combination showed a clinical benefit rate of 62.5% and an overall response rate of 26.7% among breast cancer patients previously treated with a CDK4/6 inhibitor, the companies said.

Arvinas ( ARVN ) shares were down more than 2% in recent trading, while Pfizer ( PFE ) was off by about 1%.

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