Omeros Corp. started a Phase III program to evaluate its lead inflammatory product, OMS103HP, in patients undergoing arthroscopic knee surgery.

The three double-blind, placebo-controlled, multicenter trials are expected to enroll a total of 900 patients having arthroscopic anterior cruciate ligament reconstruction, a procedure that requires the use of a miniature camera lens and surgical instruments inserted into the joint via incisions in the skin. That can result in an acute inflammatory response "initiated by a cascade of inflammatory mediators, including cytokines such as interleukins and various growth factors," said Gregory Demopulos, chairman and CEO of the Seattle-based company.

While the inflammatory response is critical for the healing process, it can result in tissue damage, scarring and severe pain if uncontrolled, Demopulos said, which can delay recovery time and the return to normal function.

Existing therapies are administered post-operatively to treat those effects, but Omeros said its lyophilized drug product is the first therapy being developed for use during surgery. OMS103HP, developed with Omeros' perioperative technology, is reconstituted and injected into standard arthroscopic irrigation solutions and "perfused through the joint in low concentrations to preemptively block the inflammatory cascade induced by surgical trauma," Demopulos told BioWorld Today.

The primary endpoint will be the improvement in knee function for patients receiving OMS103HP vs. placebo, as assessed by orthopedic surgeons and physical therapists, while secondary endpoints will include joint motion and pain management.

Demopulos said Omeros is looking to complete patient enrollment by mid-2006, and plans to file a new drug application in "late 2006 or early 2007." If OMS103HP meets with FDA approval, the product could be on the market the following year.

Omeros said about 7.3 million arthroscopic procedures were performed worldwide in 2004, with that number expected to increase by 7 percent or 8 percent every year, and initial market research suggests that its drug candidate might be acceptable to both surgical centers and third-party payers, since it is easy to use and does not affect existing surgical techniques.

The company has not agreed to any partnerships, but Demopulos said it continues to "evaluate its options" regarding commercialization.

The Phase III program is based on results from the OMS103HP Phase I/II program conducted at Stanford University in Palo Alto, Calif., which Omeros said demonstrated significant improvement in knee function. Data indicted that more than three times as many patients treated with OMS103HP met the criteria for successful pain relief while requiring lower doses of pain medication, compared to placebo. Also, 31 percent more OMS-103HP-treated patients obtained at least 90 degrees of flexion without pain, and patients in the OMS103HP group were able to stop using devices prescribed to increase post-operative joint motion 37 percent faster. No adverse effects were reported.

In addition to arthroscopic knee surgery, the company also is considering other indications for the drug within the orthopedics and surgical fields, Demopulos said.

Omeros is developing other products in its pipeline using its anti-inflammatory technologies that are in various stages of preclinical work. The next perioperative drug is expected to begin clinical studies in 2006.