If not Sirna-027 then, perhaps, Dorzolamide...
In the CC announcing the SRDX-MRK collaboration agreement, Paul Lopez stated that the relationship had begun over two years ago... This was well before the acquisition of Sirna Therapeutics by MRK in Oct 2006. Thus, I don't think that Sirna-027 is the drug that MRK will put on the I-vation implant first.
In my mind, a more promising drug in Merck’s pipeline is Dorzolamide (a carbonic anhydrase inhibitor currently used to treat glaucoma). At the May 2007 ARVO meeting, Merck (in collaboration with investigators in Denmark and Iceland) reported that Dorzolamide increases retinal oxygen tension in experimental pigs with branch retinal vein occlusion. This research provides a justification for further evaluation of Dorzolamide as a treatment for diabetic retinopathy.
Dorzolamide, like other carbonic anhydrase inhibitors, can have side-effects when delivered systemically. Up until now, Merck apparently has been focusing upon eye-drops as a topical application to avoid these side effects... If used to treat diabetic retinopathy, an implant such as I-vation would be better (in my opinion).
An implant releasing both Dorzolamide and Triamcinolone acetate, might also be worth exploring... Dorzolamide’s ability to reduce intraocular pressure would mitagate against one of Triamcinolone’s most troublesome side-effects (i.e. increased intraocular pressure).
Some background can be obtained in a recent review in Current Topics in Medicinal Chemistry by Drs. Mincione, Scozzafava, and Supuran. I have appended the abstract below....
++++
Mincione F, Scozzafava A, Supuran CT. (2007). The development of topically acting carbonic anhydrase inhibitors as anti-glaucoma agents. Curr Top Med Chem. 2007;7(9):849-54.
Carbonic anhydrase inhibitors (CAIs) such as acetazolamide, methazolamide, ethoxzolamide and dichlorophenamide were and still are widely used systemic antiglaucoma drugs. Their mechanism of action consists in inhibition of CA isozymes present in ciliary processes of the eye (such as CA II, IV and XII), with the consequent reduction of bicarbonate and aqueous humour secretion, and of elevated intraocular pressure (IOP) characteristic of this disease. Since CA II/IV/XII are present in many other tissues/organs, generally, systemic CAIs possess undesired side effects such as numbness and tingling of extremities; metallic taste; depression; fatigue; malaise; weight loss; decreased libido; gastrointestinal irritation; metabolic acidosis; renal calculi and transient myopia. In order to avoid these undesired side effects, recently, topically effective CAIs have been developed. Two drugs are available clinically: dorzolamide and brinzolamide. Both these drugs are applied topically as water solutions/suspensions, alone or in combination with other agents (such as beta-blockers, prostaglandin derivatives, etc) and produce a consistent and prolonged reduction of IOP. Furthermore, recent reports show both the systemically as well as topically acting sulfonamide CAIs to be effective in the treatment of macular oedema and other macular degeneration diseases, for which pharmacological treatment was unavailable up to now. Much research is in act in the search of even more effective topically acting CAIs, free of the inconveniences and side effects of the presently available drugs. For achieving this goal, a recently reported strategy, the tail approach, was extensively applied for the synthesis of large numbers of derivatives possessing various physico-chemical properties. Many such new sulfonamides showed promising antiglaucoma activity in animal models of the disease.
Market Data 
Markets 
AI
