Two pharma giants have teamed up to buy US biotech Amylin, responsible for the Byetta and Bydureon anti-diabetes brands

Pharma giants Bristol-Myers Squibb (BMS) and AstraZeneca have teamed up to buy US biotech Amylin for $7 billion (£4.5 billion), further strengthening their position in the burgeoning market for diabetes drugs.

Under the somewhat unconventional deal, BMS will buy Amylin outright for $31.00 per share in cash, and then AstraZeneca will buy into the venture for $3.5 billion.

Amylin specialises in type 2 diabetes. Its key drug is exenatide, a synthetic version of hormone found in the saliva of the Gila monster, a large, venomous lizard found in the southern states of the US and northern Mexico. In the human body, it acts as an agonist for a molecule produced in the human gut to control levels of glucose and insulin: glucagon-like peptide-1 (GLP-1).

The drug is marketed in two forms: Byetta injections, taken twice a day, and Bydureon injections, taken once a week. It was approved by US authorities in 2005, and since then has been a relatively successful drug: in 2011, it brought it sales of about $1 billion, split between Amylin and long time collaborator Eli Lilly.

But recently it has caused disagreement. In November 2011, Amylin and Lilly agreed to end their partnership prematurely – with Amylin taking back full rights to exanatide – following a row over alleged conflicts of interest. In January, Lilly had aggravated its partner by entering an agreement with German drug maker Boehringer Ingelheim – a deal relating to another diabetes drug, linagliptin, marketed as Tradjenta.

There is some precedent for the BMS and AstraZeneca deal – they already work together in the diabetes area as part of a collaboration agreed in 2007. Both companies will now be hoping for strong sales of Bydureon injections, approved in Europe in June 2011.