In the latest show of faith in the potential of gene-silencing technology, GlaxoSmithKline has teamed up with Sirna Therapeutics to develop RNA interference-based drugs to treat respiratory diseases. GSK will make an initial payment of $12 million comprising cash and investment in Sirna stock. Sirna says it could rake in another $700 million in milestone payments and royalties on potential product sales. Sirna will supply optimized and formulated short interfering RNAs against targets generated by both companies. GSK will then conduct all preclinical and clinical development of the compounds and will commercialize any products that come out of the alliance. The deal between GSK and Sirna underscores major drug companies' growing interest in adding RNAi-based drugs to their pipelines. In February, Novartis expanded its relationship with Alnylam Pharmaceuticals to develop RNAi therapeutics for pandemic flu. Alnylam also has a relationship with Merck, while Sirna is developing eye disease drugs with Allergan.