Bristol-Myers Squibb (BMS) has officially started its tender offer for Amylin Pharmaceuticals, the first stage in a process that will see the diabetes specialist become a BMS subsidiary and the focal point of an alliance with AstraZeneca (AZ).
Last month, BMS said it would buy Amylin for $5.3bn and pay off a $1.7bn debt owed to the company's former partner Eli Lilly.
Under the terms of the deal, AZ will then make a $3.4bn payment to BMS in return for 50 per cent of the profits from Amylin's products, which include diabetes drug Byetta (exenatide) and once-weekly follow-up Bydureon.
The combined offer is rumoured to have been made after a solo bid for Amylin from BMS of around $3.5bn was rejected.
AZ already has a wide-ranging diabetes partnership with BMS covering drugs such as Onglyza (saxagliptin), Kombiglyze (saxagliptin and metformin) and Forxiga (dapagliflozin), and has negotiated a $135m option to take equal governance of the expanded alliance.
In addition to Byetta and Bydureon, the acquisition will give BMS and AZ rights to Symlin (pramlintide acetate) injection, an amylin analogue which is already approved for the treatment of type 1 and type 2 diabetes patients with inadequate glycaemic control on meal-time insulin.
Amylin's pipeline also comes under the control of the alliance, and is headed by metreleptin, an analogue of the human hormone leptin which is being studied as a potential therapy for certain metabolic disorders in patients with inherited or acquired lipodystrophy. Metreleptin is currently under regulatory review in the US.
BMS said its $31-per-share tender offer for Amylin expires on August 7, 2012, but is open for extension.
Amylin's shareholders are expected to get behind the offer, which is described by investment research firm Zacks as "financially rewarding" for investors, although some analysts have suggested the price being paid for Amylin's assets is high.