Genelabs Technologies Inc has submitted to the U.S. Food and Drug Administration (FDA) its protocol for a Phase III clinical trial for Prestara (prasterone), the company's investigational drug for systemic lupus erythematosus (SLE or lupus).
In late August, the FDA completed its review of the Prestara New Drug Application (NDA) and issued an approvable letter to Genelabs. Approval is contingent upon, among other things, the successful completion of an additional clinical trial providing sufficient evidence to confirm the positive effect on bone mineral density that was observed in Genelabs' previous Phase III Study GL95-02. Since receipt of the approvable letter, Genelabs has been working with the FDA and noted experts to design a clinical trial intended to provide additional evidence of efficacy to support the approval of Prestara for marketing in the United States.
The protocol submitted describes a clinical trial that will be a multicenter, randomized, placebo-controlled, double-blind study to be conducted at leading U.S. medical centers. The primary endpoint is bone mineral density at the lumbar spine. The protocol provides for approximately 110 women with SLE receiving glucocorticoids to be enrolled in the trial and treated for six months with either 200mg/day Prestara or placebo.
"The bone mineral density results observed in Study GL95-02 are exciting because Prestara demonstrated a significant positive effect and the effect was robust. Damage to the musculoskeletal system is the most frequent area of damage in lupus patients. Based on the results from Study GL95-02 and our recent meeting with the FDA, we have designed and submitted a protocol for a confirmatory Phase III clinical trial," said Irene A. Chow, Ph.D., chairman and chief executive officer of Genelabs. "This is an important milestone in Genelabs' development of Prestara, and we currently plan to initiate the trial before the end of 2002."
As part of Genelabs' previous Study GL95-02, which had a treatment duration of 12 months, baseline and post-treatment measurements of bone mineral density were taken for women with lupus on low-dose glucocorticoids. In the analyses, the mean percentage change in bone mineral density of both the lumbar spine and hip significantly increased in the group of patients treated with Prestara, compared to decreases in the placebo group. The differences between groups were statistically significant favoring Prestara at both the lumbar spine (n=55, p=0.003) and hip (n=53, p=0.013).
Lupus is a severe, chronic and frequently debilitating autoimmune disease that can affect the musculoskeletal and nervous systems as well as the lungs, heart, kidneys, skin and joints. Scientific publications have reported that the most common form of organ damage among lupus patients, musculoskeletal damage, occurs in 22 per cent of patients, followed by neuropsychiatric disorders in 20 per cent of lupus patients and renal disease in 15 per cent. In the United States, there have been no new drugs approved by the FDA for the treatment of lupus in more than 40 years. Existing treatments for lupus are often inadequate, due to limited benefits and severe adverse side effects. According to various published estimates, lupus affects approximately 200,000 patients in the United States, and Genelabs believes that there are at least one million patients worldwide.