Pfizer Inc. scientists in Groton and New London were heartened over the weekend by the release of a late-stage drug trial showing the company's experimental rheumatoid arthritis pill reduced pain and inflammation for nearly three-quarters of disease sufferers.
Results from the study of tasocitinib, released Sunday before being presented this week at the American College of Rheumatology meeting in Atlanta, were hailed as the indication of a major breakthrough. The current prevailing treatments for rheumatoid arthritis are all injectable drugs.
"We have not had any oral drug in rheumatoid arthritis with positive Phase 3 data in the past decade," said Saeed Fatanejad, Pfizer's head of late-stage trials on tasocitinib, in a phone interview. Fatanejad said regulatory approval of the drug, not expected for a year or two at the earliest, would represent "another choice for patients and physicians."
Fatanejad added that more studies of tasocitinib - pitting the pill's effectiveness against that of current treatments - won't be completed until midway through next year. He said 20 to 40 percent of rheumatoid arthritis sufferers do not respond to current therapies.
Rheumatoid arthritis, which is most likely to strike people in their 40s and 50s, is tied to an overactive immune response that attacks tissues, causing intense pain and the twisting of joints. The chronic disease is believed to affect 1 to 2 percent of the world's population, leading analysts to project that tasocitinib could add billion in sales to Pfizer's bottom line in a market for rheumatoid-arthritis drugs estimated to be billion.
Other companies are currently in the race to develop rheumatoid athritis pills, but Fatanejad said Pfizer's so-called JAK inhibitor is the only one currently in late-stage trials.
The discovery of an enzyme that led to the development of the JAK inhibitor occurred in the Groton labs in 1993, overseen by Paul Changelian, who has left Pfizer. The company then collaborated with academic researchers to survey potential compounds and, around 2000, came across the JAK inhibitor.
The drug is a immune-system suppressant that works by blocking a receptor on cells called JAK-3.
Samuel Zwillich and Bernhardt Zeiher, headquartered at Pfizer's New London campus, led development efforts for the drug. Tasocitinib also is being studied for possible use in fighting Crohn's disease, psoriasis and inflammatory bowel disease, as well as in suppressing the immune response during transplants of solid organs.