Archemix Corp. and Nuvelo, Inc. announced that they have expanded their collaboration agreement. Under the new agreement, which replaces the existing 50/50 collaboration, Archemix will be responsible for the discovery of short-acting aptamers targeting the coagulation cascade for use in acute cardiovascular procedures, and Nuvelo will be responsible for the development and worldwide commercialization of these aptamers. In addition, Nuvelo has designated NU172 (ARC2172), a short-acting, direct thrombin inhibiting aptamer, as a development candidate.

Under the new collaboration agreement, Nuvelo will make an initial upfront payment to Archemix of $4.0 million and, under certain circumstances may invest up to $10.0 million, in Archemix's common stock upon an initial public offering. Nuvelo will also fund Archemix research in the area of short-acting aptamers for the next three years at a minimum of $5.25 million. In addition, Archemix may receive payments totalling up to $35.0 million per development compound on the achievement of specified development and regulatory milestones, along with potential royalty payments based on sales of licensed compounds. At the initiation of the first phase 3 study for any licensed compound, Archemix has the option to elect to participate in profits from sales of the compound by funding its pro rata share of prior and future product development and commercialization expenses, in lieu of receiving milestone payments and royalties with respect to that compound.

"The development of anticoagulants with rapid onset and offset of action continues to represent a great opportunity as there is an unmet medical need for an anticoagulant with fewer side effects and more predictable dosing than heparin combined with its antidote, protamine," stated Dr Ted W. Love, chairman and CEO of Nuvelo. "This strategic alliance with Archemix maximizes our respective core competencies, Archemix's unparalleled expertise in the identification and optimization of aptamers and Nuvelo's cardiovascular development capability. It will also allow both companies, to benefit from the acute cardiovascular commercial infrastructure, that we are putting in place to support the launch of our lead compound, alfimeprase."

"The expansion of our existing collaboration highlights the potential of aptamers as a novel source of therapeutics," stated Dr Errol De Souza, president and CEO of Archemix. "Although the original molecule developed under the prior agreement, ARC183, demonstrated proof of concept in the clinic, it was not optimal for further clinical development due to its lower potency. The rapid discovery cycle times associated with aptamers allowed us to generate a more potent development candidate, NU172, within one year of initiation of the project. Recognizing the potential of NU172 and the need for short-acting anticoagulants in general, Nuvelo elected to expand our collaboration and build upon the foundation of clinical learning we achieved during the term of our original agreement. We are very enthusiastic about expanding our collaboration with Nuvelo and leveraging each others' strengths to the mutual benefit of the collaboration."

NU172 is an aptamer, which directly inhibits thrombin's ability to generate fibrin, the protein that provides the scaffolding for blood clots. Data from early animal models suggest that NU172 is a potent anticoagulant that offers the potential for predictable anticoagulant effects, rapid onset and offset of action, reduced bleeding complications and no risk of heparin induced thrombocytopenia. Nuvelo has already commenced IND-enabling studies with NU172.

Aptamers are single-stranded nucleic acids that form well-defined three-dimensional shapes, allowing them to bind target molecules in a manner that is conceptually similar to antibodies. Aptamers combine the optimal characteristics of small molecules and antibodies, including high specificity and affinity, chemical stability, low toxicity and immunogenic and the ability to target protein-protein interactions. In contrast to monoclonal antibodies, aptamers are chemically synthesized rather than biologically expressed, offering a significant cost advantage.