Firms have been in a discovery partnership since July 2011.

Amgen and Micromet entered into a definitive agreement for Amgen to acquire Micromet for roughly $1.16 billion. The $11 per share cash offer has been approved by both the Amgen and Micromet boards of directors. The deal represents a 33% premium to Micromet’s $8.27 closing price yesterday. Today, Micromet’s share price has jumped to $10.93 in early morning trading.

Amgen’s decision to buy Micromet outright comes some six months after the firms inked a collaboration deal. For €10 million up front, Micromet agreed to work to discover antibodies against three undisclosed tumor targets from Amgen, which agreed to pay a further €342 million in clinical and commercial milestone payments plus double-digit royalties.

The acquisition gives Amgen Micromet’s Bispecific T cell Engager (BiTE) antibody technology. The most advanced candidate, blinatumomab, is being evaluated as a treatment for hematological malignancies. “The acquisition of Micromet is an opportunity to acquire an innovative oncology asset with global rights and a validated technology platform with broad potential clinical applications,” remarks Kevin Sharer, chairman and CEO at Amgen.

Blinatumomab is currently under investigation in five trials: two Phase II trials for adult patients with relapsed/refractory ALL, Phase I/II trial for pediatric patients with relapsed/refractory ALL, Phase II trial for adult ALL patients with minimal residual disease, and a Phase I trial for adult patients with relapsed/refractory NHL.

Micromet has ongoing partnerships with companies including Sanofi, Bayer Schering Pharma, and Boehringer Ingelheim. Amgen also adds Micromet’s R&D center in Munich. The site will operate as an Amgen R&D center of excellence.

Around this time last year Amgen reported that it was going to pay $425 million in cash to take over cancer and infectious disease vaccines firm BioVex. It also agreed to another $575 million in regulatory and sales milestones. BioVex’ lead candidate, OncoVEXGM-CSF, is currently being evaluated in a Phase III multinational study in metastatic melanoma, and a separate Phase III study in squamous cell carcinoma of the head and neck.