Sirnaomics this week said it has signed a deal to collaborate with General Research Laboratory to develop siRNA-based treatments for prostate cancer and wound healing without scars.
A Sirnaomics official also said that the company continues to expect that it will launch a phase I study of its lead RNAi drug candidate, the ocular disease therapy STP-601, this year, but has not yet decided in what country — the US or China — to conduct the study.
Under the collaboration with GRL, the company will provide Sirnaomics with “several million” dollars in research funding and milestones, Sirnaomics President, CEO, and founder Patrick Lu told RNAi News this week. Sirnaomics also stands to receive royalties on product sales, and will continue to have access to office and laboratory space provided by GRL under a July 2007 arrangement between the firms.
Lu said that the arrangement is structured as a 50/50 partnership, so Sirnaomics will retain certain commercial rights to both drugs if they are commercialized. A marketing strategy, however, has not been finalized.
Still, Asghar Ghias, executive vice president at GRL, told RNAi News that his company would likely market products, such as the wound-healing drug, to military customers since the company is primarily interested in bio-defense and battlefield medicine.
The partnership has an initial three-year term and includes renewal options. Lu said that Sirnaomics and GRL anticipate filing INDs for both drug candidates around the end of 2009.
According to Lu, the wound-healing drug candidate is expected to include three siRNAs targeting undisclosed genes involved in scar formation and will be delivered as a topical cream using a polymeric nanoparticle technology.
Topical delivery of siRNAs has proven to be particularly challenging. As reported by RNAi News, Sirna Therapeutics’ now-defunct dermatology division hit major technological hurdles in trying to develop a topical, siRNA drug for permanent hair removal (see RNAi News, 1/24/2008).
Meanwhile, TransDerm, which many in the industry view as having made the biggest strides in topical siRNA delivery, recently opted against testing a topically administered version of its investigational pachyonychia congenita therapy in a phase Ib trial (see RNAi News, 1/17/2008). Instead, the company is evaluating the drug when delivered through intradermal injections.
However, Lu pointed out that Sirnaomics’ wound-healing drug isn’t expected to face the same challenges as these other drug candidates since it would be applied to an open wound, not unbroken skin.
“We learned that in China, after you file an [investigational new drug application], you usually have to wait 9 to 12 months.”
As for the prostate cancer program, Lu said that Sirnaomics and GRL intend to develop an siRNA cocktail targeting three undisclosed genes linked to tumor formation, which will be delivered locally using GRL’s so-called epoxy encapsulated magnetic nanoparticle technology.
Ghias said that this nanoparticle technology was developed at Howard University while he was working with a team of biophysicists studying the “magnetic susceptibility of particles, in general.
“We worked on this [along with collaborators at Catholic University] for several years then looked into potential medical applications, especially as a cancer therapy,” by using a strong, externally generated magnetic field to guide the nanoparticles throughout the body to target tissues, he said.
Ghias noted that the Howard researchers had built a prototype device that could generate the required magnetic field, but characterized this work as “in the earlier stages” of development. GRL holds the commercial rights to the technology, Ghias added.
Eyeing China and the US
Lu confirmed that Sirnaomics still plans to begin phase I testing of STP-601 this year, but may run the trial in the US after originally planning to conduct it in China, where regulatory hurdles are typically lower (see RNAi News, 9/20/2007).
“We learned that in China, after you file an [investigational new drug application], you usually have to wait 9 to 12 months” — longer than Sirnaomics had expected, he said. As a result, Sirnaomics plans to file the necessary paperwork to begin human testing of STP-601 in both the US and China. The company would then launch the trial wherever clearance is obtained first.
Lu added that a pre-IND meeting has been scheduled with US Food and Drug Administration officials and that Sirnaomics is working with an undisclosed contract research organization to put together a pharmacology and toxicology package.
SPT-601 is being developed as a locally administered drug capable of treating diabetic retinopathy, herpetic stromal keratitis, and wet age-related macular degeneration. It comprises a cocktail of multiple siRNAs targeting three genes associated with neovascularization: vascular endothelial growth factor, or VEGF; and MMP-9 and MMP-2, two genes in the matrix metalloproteinase pathway.
By incorporating multiple siRNAs into a single drug, Sirnaomics expects that it can achieve better efficacy than other siRNA treatments for ocular diseases, such as Opko Health’s phase III wet age-related macular degeneration candidate bevasiranib, while maintaining a similar safety profile.