The pharmaceutical company has added $6.3m to the $17m raised from backers including Novartis, Pfizer and Partners Innovation Fund last year.

Quartet Medicine, a US-based developer of therapies to treat chronic pain and inflammation, closed a series A round backed by pharmaceutical firms Novartis and Pfizer at $23.3m yesterday.

Novartis Venture Fund and Pfizer Venture Investment, respective corporate venturing arms of Novartis and Pfizer, and Partners Innovation Fund, which is backed by Brigham and Women’s Hospital and Massachusetts General Hospital, contributed funds to a $17m first tranche in October 2014.

The first tranche was led by venture capital firm Atlas…