Though it bills itself as an ophthalmic drug company, Acuity Pharmaceuticals continues to make a name for itself in the RNAi field.
Last week, the company announced that it had in-licensed from ZaBeCor an siRNA targeting Syk kinase and related intellectual property for ophthalmic indications. Specific terms of the deal, which gives Acuity its second RNAi-based drug candidate, were not disclosed.
According to the companies, the Syk kinase gene is a "key cell-signaling molecule that has been shown to be central in initiating critical elements of the inflammatory response in a number of disease models." ZaBeCor is developing the Syk kinase-targeting siRNA under the name Excellair for asthma and other disorders associated with respiratory inflammation.
But according to the companies, "preliminary data" suggest that Excellair may be useful in ocular inflammatory conditions such as uveitis and ocular allergies, and might be able to "prevent the inflammation that contributes to vision loss in degenerative conditions such as macular degeneration."
Supporting these findings is a US patent application, No. 20050075306, which claims the use of an siRNA to target Syk kinase for inflammatory conditions of the bronchi, lungs, eyes, bladder, or skin. The patent application, which was filed on July 1, 2004, listed ZaBeCor founder Alan Schreiber as the lead inventor.
"Preliminary data suggest that Excellair may have utility in inflammatory conditions of the eye, including uveitis and ocular allergies, and it also may have the potential to prevent the inflammation that contributes to vision loss in degenerative conditions such as macular degeneration."
Dale Pfost, president and CEO of Acuity, declined to comment on which ocular diseases are likely candidates for intervention with ZaBeCor's siRNA, saying only that "when you talk about inflammation in ophthalmology, there are several different indications implicated — some at the back of the eye and some at the front of the eye.
"Anti-inflammatory [drugs] in the form of steroidal or steroidal-like drugs have been a long-standing class of medicine, [but] have negative consequences, so an alternative to steroidal-like drugs is certainly attractive to ophthalmologists," he added. "We will be undertaking … over the next few months … a prioritization of which of the indications within the eye that we'll move forward most aggressively with in clinical development. It certainly covers a range within ophthalmology."
Pfost also declined to state the company's newly licensed siRNA is modified, but said that "we'll be optimizing the compound as appropriate for the indication." Acuity's other RNAi therapeutic candidate is an unmodified siRNA in clinical development for age-related macular degeneration and diabetic macular edema. Acuity recently completed a phase II AMD study of the drug, called Cand5, and said last week that it has finished enrolling patients in a phase II trial for DME.
"We have a very pragmatic view relating to developing drugs for ophthalmology," Pfost said. "Cand5 is an unmodified siRNA because we believe that it is the most appropriate form of molecule for delivery to the eye." However, various factors, including the route of administration — whether it be topical, intravitreal, or sustained release — will determine how an RNAi drug candidate is ultimately formulated, he noted.
According to Pfost, the genesis of the ZaBeCor deal stems from a long-term personal relationship between the founders and management of the two companies due to a common interest in RNAi and the fact that both firms are located in Philadelphia. Additionally, ZaBeCor founder Alan Schreiber and Acuity co-founder Samuel Reich are both faculty members at the University of Pennsylvania.
"That relationship led to the recognition that there was the opportunity to pursue an ophthalmic set of indications with [ZaBeCor's siRNA drug] and that [Acuity] had … the expertise necessary to pursue them," Pfost told RNAi News last week. "It was the natural outcome of an interpersonal relationship that was developed between the companies over a couple of years. It's been a long time incubating."
Officials from ZaBeCor were not available for comment by press time.
— Doug Macron ([email protected])