Teva Pharmaceutical Industries has shelled out for exclusive rights to Mersana Therapeutics’ novel cancer candidate XMT-1107, in a deal potentially worth $334 million.

The companies have entered into a research and exclusive license pact to develop and commercialise XMT-1107 - a novel anti-angiogenic agent that uses Mersana’s Fleximer polymer platform - in cancer and all other indications.

Mersana’s Fleximer is a biodegradable, bio-inert polymer that can be chemically attached to small molecules, biologics and nucleic acids to boost their pharmacokinetic and safety profiles and, according to the firm, has been proven to transform both existing and experimental drugs into “new, patentable drugs with superior properties”.

XMT-1107 consists of Fleximer and a novel analog of fumagillin, which prevents the formation of new blood vessels and so has potential as a treatment for various diseases. But while fumagillin analogs have demonstrated anti-tumour activity in early and mid-stage clinical trials, their subsequent development has to date been hampered by pharmacokinetic issues and reversible central nervous system toxicity in patients.

Preclinical pharmacology studies with XMT-1107, however, have shown that this version of fumagillin has “a significantly improved pharmacokinetic profile as well as no evidence of CNS toxicity”, the firm said, raising hopes that it might just overcome the obstacles observed with its predecessors.

Deal terms
Under the terms of the deal, Teva has bought itself an exclusive worldwide license to XMT-1107 excluding Japan - which Mersana has decided to hang on to - in return for picking up the tab for all clinical development of the candidate relevant to its territories. In addition, Mersana stands to receive up to $334 million if all development, regulatory and commercial milestones are met, as well as royalties on the sales if the product makes it to market.

Explaining the strategy behind the move, Mersana’s chief executive Julie Olson said the deal will provide “the necessary resources for XMT-1107 to achieve broad therapeutic potential”, while Aharon Schwartz, Vice President of Teva Innovative Ventures, said his firm is “impressed by Mersana’s success with the Fleximer technology and the potential of XMT-1107”.

Mersana said it plans to initiate a Phase I clinical trial for XMT-1107 in the second quarter of 2010.