Pfizer's new RA treatment shows promise

Pfizer has announced data from two clinical studies of its developmental rheumatoid arthritis candidate.

CP-690550 is the first in a new class of drugs which inhibit the JAK family of enzymes. These enzymes play a part in the signaling of multiple cytokines (proteins released by cells to communicate with other cells) that are involved in a broad spectrum of inflammatory and autoimmune diseases.

The drug is also being evaluated as a treatment for psoriasis, Crohn's disease, ulcerative colitis and solid organ transplant.

If it can prove to be successful in one or more of these areas, the drug will help Pfizer break into one of the industry's most lucrative and fastest-growing therapy areas, currently dominated by drugs such as Wyeth's Enbrel and Johnson & Johnson/Merck's Remicade.

Pfizer's drug showed statistically significant response and remission rates when given alone or in combiantion with methotrexate for patients with active rheumatoid arthritis.

The findings were presented at the 2009 ACR/ARHP meeting in Philadelphia, representing the final analyses from two phase II trials evaluating CP-690550 over 24 weeks.

"These data suggest that CP-690550 could represent a promising advance for patients with rheumatoid arthritis," said Michael Berelowitz, senior vice president of clinical development and medical affairs for Pfizer Specialty Care. "Our phase III programme is currently underway with enrollment progressing as planned, and we are hopeful that data from these trials will validate the phase II results."