Thiarabine shows promise for rheumatoid arthritis

Jul 7 2009

Access Pharmaceuticals, Inc. announced today new preclinical data demonstrating that thiarabine shows remarkable efficacy in the prevention and treatment of rheumatoid arthritis (RA).

In a well-established animal model for RA, an exceptional restoration of joint structure was observed in the studies, which were conducted at Wayne State University School of Medicine and at Southern Research Institute.

As a therapeutic treatment of established disease, thiarabine demonstrated a highly significant, dose-dependent amelioration of arthritis. Thiarabine treatment resulted in a broad inhibition of disease pathology, with reduction of both inflammatory and erosive disease parameters, as well as protection from loss of cartilage matrix proteins. When used as a preventative treatment, thiarabine blocked the development of joint disease at the 60 mg/kg/day dose level and exhibited a significant reduction in disease incidence and severity at 20 mg/kg/day.

In a therapeutic study comparing thiarabine to methotrexate, a commonly used clinical drug for RA treatment, high resolution 3-D images from an X-ray microtomograph were used along with histological scoring to evaluate joint and bone destruction. Thiarabine demonstrated statistically significant anti-arthritic efficacy comparable to that of methotrexate. "The images from X-ray microtomography present a compelling visual representation of diseased vs. treated limbs" commented David Nowotnik, Senior Vice President Research and Development. "We are delighted with the results of the preclinical study which demonstrate a real benefit to the use of thiarabine in RA."

"Our current development focus for thiarabine is for the treatment of hematological cancers," stated Jeffrey B. Davis, President & CEO. "But, we believe these new RA data provide compelling evidence that Thiarabine should be developed for rheumatoid arthritis as well."

Thiarabine is a next generation nucleoside analogue that Access has licensed from Southern Research. It has been in two Phase 1/2 solid tumor trials and was shown to have significant anti-tumor activity. Access is now working with leukemia and lymphoma specialists to initiate additional Phase 2 clinical trials in acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL) and other indications. "The IND for thiarabine has been transferred to Access and we have a supply of clinical-grade material." continued Dr. Nowotnik. "We should be able to start the study shortly after FDA clearance of the protocol and drug recertification."