FLINT, Mich. — UnitedHealth Group pharmacy benefit manager OptumRx on Monday announced plans to purchase specialty drug provider Diplomat Pharmacy Inc. for about $300 million. The news comes amid continued financial struggles for Diplomat. In the third quarter, the company reported a $177 million net loss.

In a statement, Diplomat chairman and chief executive officer Brian Griffin said the decision to merge is “in the best interests of our shareholders, employees, and the clients and patients we serve.”

Founded in 1975, Diplomat provides specialty drugs – such as medications for cancers and immune disorders – in all 50 states and Washington, D.C. Once valued at more than $3 billion, the company now owes more than $560 million in debts. Last month, the company told investors it may have trouble making its debt payments.

“As we take into account lower than expected third quarter results, our reduced 2019 outlook and continued industry headwinds, it is possible we may be in violation of covenants for the period ending Dec. 31, absent the successful execution of mitigating strategies,” Griffin said in a Nov. 12 earnings call.

Diplomat announced in August a review of its options, including putting itself up for sale, in the wake of customer losses in its pharmacy benefits management (PBM) business. The deal is the latest from UnitedHealth to expand its specialty pharmacy business and would help build out its footprint of lower-cost home infusion therapy services.

Last year, the largest U.S. health insurer acquired Phoenix-based specialty pharmacy Avella and acquired Genoa Health, which runs pharmacies in behavioral health clinics.