Array BioPharma Inc. said lead drug candidate ARRY-797 met its primary and secondary endpoints of relieving postsurgical dental pain in its first Phase II trial.

Boulder, Colo.-based Array is preparing to initiate two additional Phase II trials with the drug.

A 250-patient Phase II dental pain trial comparing three doses of ARRY-797 to placebo and to Celebrex (celecoxib, Pfizer Inc.) is scheduled to begin in the coming weeks. Following in the third quarter is a Phase II trial in ankylosing spondylitis.

While ARRY-797 is looking good in pain, the ankylosing spondylitis trial could open the door to a second large market: inflammation.

Many inflammatory diseases are treated with blockbuster tumor necrosis factor (TNF)-alpha inhibitors like Enbrel (etanercept, Amgen Inc.), Remicade (infliximab, Centocor Inc.) and Humira (adalimumab, Abbott).

Yet ARRY-797 is a small molecule rather than a biologic, offering the potential for oral dosing and less expensive manufacturing, said Array spokeswoman Tricia Haugeto.

Array Chief Medical Officer John Yates added that ARRY-797 is a p38-alpha inhibitor, modulating not just TNF but other cytokines including IL-1, IL-6 and PGE2.

The acute pain relief provided by the PGE2 modulation helps patients feel better immediately, while the inhibition of TNF and other cytokines improves inflammation over time and is expected to provide "some benefit in terms of disease modification," Yates said.

Although anti-inflammatory action remains to be tested, the recently completed Phase II trial demonstrated that 400 mg of ARRY-797 caused a statistically significant improvement in total pain relief (p<0.0001) six hours after administration. Statistically significant improvement also was seen three, eight, 12 and 24 hours post-dose as well as according to secondary endpoints such as pain intensity and time to pain relief.

The randomized, double-blind, placebo-controlled, 103-patient Phase II trial also evaluated ARRY-797 dosed at 200 mg both before and after molar extraction, a strategy that resulted in a substantial reduction in total pain intensity.

The drug was well tolerated, and no serious adverse events were reported.

Detailed data will be submitted to a scientific conference for presentation "around midyear," Haugeto said.

The initial Phase II data boosted Array's stock (NASDAQ:ARRY) 96 cents, or 17 percent, on Monday to close at $6.56.

That boost helped ease the pain of a stock slump sparked late last year by partner AstraZeneca plc's announcement that MEK inhibitor AZD6244 (ARRY-886) failed a Phase II melanoma trial.

The failure spooked some investors, but analysts maintained that it was not an indictment of Array's whole pipeline and attributed much of the blame to trial design. (See BioWorld Today, Dec. 21, 2007.)

London-based AstraZeneca still is testing AZD6244 in several signal searching studies. The big pharma is also in Phase I with another drug licensed from Array. (See BioWorld Today, Dec. 19, 2003.)

Array has several discovery deals with Celgene Corp., Eli Lilly and Co., Amgen Inc., Genentech Inc. and others, but investors are most excited about the company's internal pipeline.

That pipeline includes the Phase II MEK inhibitor ARRY-162 for rheumatoid arthritis and the ErbB-2/EGFR inhibitor ARRY-543, which is on the brink of beginning a Phase II trial for breast cancer.

KSP inhibitor ARRY-520 is finishing Phase I and is expected to begin Phase II trials this year in acute myeloid leukemia. Meanwhile, ErbB-2 inhibitor ARRY-380 is in Phase I, and p38/Tie-2 inhibitor ARRY-614 is slated to begin Phase I in the first half of the year.

So far, all of Array's internal programs are unpartnered. Yates said the company plans to partner ARRY-797 but wants to finish the Phase II pain and ankylosing spondylitis trials first.