Quark Pharmaceuticals, a Californian based RNAi specialised biotech company, has announced changes to a Pfizer collaborative research agreement following receipt of results from a randomized Phase II clinical study. Quark’s and Pfizer’s Global Licensing Agreement is understood to cover the RTP801 gene and modifiers thereof, with the intention for the companies to develop therapeutic strategies for a range of indications, including the use of siRNA to down regulate RTP801 expression in AMD and DME patients.