The Swiss company said the capacity, operated at the larger of its two active pharmaceutical ingredient (API) manufacturing plants, will initially be used for commercial production of Celgene's Revlimid API, commencing in early 2007.
Siegfried will receive an initial payment of €9.4m from Celgene under the terms of the agreement.
The manufacturing facility in Zofingen has been approved by US and European regulatory authorities to produce and supply drug substances to both markets.
Revlimid (lenalidomide) is used in combination with dexamethasone for the treatment of multiple myeloma, and also indicated for the treatment of patients with transfusion dependent anaemia.
The two companies have entered into a broad-ranging alliance under the new deal, with Siegfried supplying chemical intermediates, analytical testing and technical support services to Celgene.
"This asset acquisition and collaboration further extends our global manufacturing set-up and supports our objective to strategically control the production of Revlimid worldwide," said Robert J. Hugin, President and COO of Celgene.
In May 2005 Siegfried acquired US based controlled API manufacturer Penick Corporation, which involved Penick moving its activities to Siegfried's Pennsville site. Siegfried's production facility is Celgene's latest addition, following the acquisition of biotherapeutics and cord blood banking business Anthrogenesis in December 2002, and biopharmaceutical firm Signal Pharmaceuticals in August 2000.