ROCKVILLE, Md. (
) --The beneficial effect of
Human Genome Sciences'
experimental lupus drug Benlysta wanes over time, according to updated results from a phase III study released Tuesday.
The results caused Human Genome shares to fall 9.5% to $28.50 in early Tuesday's trading.
Human Genome said 38.5% of patients responded to treatment with a high dose of Benlysta after 76 weeks compared to 32.4% of patients treated with a placebo, a difference that was not statistically significant.
were first announced in November, the high-dose Benlysta patients reported a 43.2% response rate after 52 weeks of treatment compared to a 33% response rate for placebo -- a result that was statistically significant.
The primary endpoint of this phase III study was designed to measure the effect of Benlysta after one year of treatment, so the study was a success. The waning benefit of Benlysta for lupus patients measured 18 months after treatment, however, could influence doctors to treat lupus patients for a shorter period of time with Benlysta. That might affect the drug's commercial sales potential.
Human Genome and partner
are expected to seek regulatory approval for Benlysta later this year. The approval applications are based on two positive phase III studies of Benlysta.
"A positive overall picture has emerged from our pivotal Phase 3 studies of Benlysta, including its achievement of statistical significance on the primary efficacy endpoint at Week 52 with a favorable safety profile in both BLISS-52 and BLISS-76," said Thomas Watkins, Human Genome's CEO, in a statment. "We view the results of these studies as strongly supportive of our view that Benlysta has the potential to become the first new approved drug in more than 50 years for people living with systemic lupus."
-- Reported by Adam Feuerstein in Boston.
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