The same day London-based GlaxoSmithKline plc closed its $1.65 billion acquisition of specialty pharma firm Reliant Pharmaceuticals Inc., Reliant stakeholder Alkermes Inc. received a $166.3 million payment.

Cambridge, Mass.-based Alkermes, which has held a stake in Reliant since the companies signed a partnership in 2001, also will be due an additional $7.7 million, subject to terms and conditions of an escrow arrangement that will remain in effect for 15 months after closing. Alkermes has said it plans to use proceeds, along with existing cash, to repurchase shares of its common stock. The company's board authorized management in November to begin repurchasing up to $175 million of its common stock using proceeds from the Reliant stake sale and existing cash.

As of Sept. 30, Alkermes cash position totaled about $362.9 million.

The company's shares (NASDAQ:ALKS) gained 66 cents, to close Wednesday at $14.88.

Under the 2001 marketing deal, Alkermes made a $100 million investment in Reliant, acquiring 19 percent of the Liberty Corner, N.J.-based firm. The companies were expected to merge their operations in 2002, but those plans were derailed after Alkermes' long-acting schizophrenia drug Risperdal Consta was deemed non-approvable by the FDA. That product later was approved and is marketed by a unit of Johnson & Johnson.

Prior to GSK's buyout, Reliant had a pending initial public offering, in which it hoped to raise as much as $400 million in the public markets. But those plans became moot last month after the London-based big pharma firm offered $1.65 billion for the company. That deal adds several cardiovascular programs to GSK's portfolio, including Lovaza (omega-3-acid ethyl esters), an FDA-approved treatment for patients with high levels of triglycerides, as well as DynaCirc CR (isradipine) and InnoPran XL (propranolol HCl), which treat high blood pressure. GSK also picks up Rythmol SR (propafenome), an arrhythmia drug.

At the time of the acquisition, about 60 percent of Reliant was owned by three investors: Alkermes, PharmBay Investors LLC and Bay City Capital LLC.