A two-year rat carcinogenicity study of Gattex was performed with clean results. A similar study in mice is still being conducted but NPS Pharma has an agreement with FDA to finish the study after Gattex is approved.
European regulators reviewed all these safety data and found no link between Gattex and cancer.
SBS patients rely on intravenous feeding -- known as parenteral nutrition -- for the liquid nutrients they need to survive. The average SBS patient enrolled in the NPS Pharma studies required approximately 12 liters of parenteral nutrition per week. Gattex works by increasing the nutrient absorption rate of the intestines, thereby reducing the amount of parenteral nutrition that SBS patients require.
In the phase III study, 63% of SBS patients responded to treatment with Gattex after six months compared to 30% of similar patients treated with a placebo. This outcome -- the study's primary endpoint -- was highly statistically significant. Response was defined as a 20% or greater reduction in weekly parenteral nutrition volume.
The phase III study was not conducted under a Special Protocol Agreement with FDA although NPS Pharma has said FDA officials were consulted on the trial design and agreed with the primary endpoint used.
In other analyses of the trial data, Gattex-treated patients reduced their average weekly parenteral nutrition requirements by 4.4 liters, or a 35% reduction. By comparison, placebo patients reduced their parenteral nutrition by 2.3 liters, or 17%. The difference between the two groups was also statistically significant.
Also, 54% of Gattex patients were able to reduce the number of infusion days per week by one or more days, more than double the 23% reduction for placebo-treated patients. Mean body weight of Gattex-treated patients remained unchanged.
Whether or not reductions in parenteral nutrition represent a meaningful clinical benefit for SBS patients is likely to come up as a topic of discussion and debate at next week's FDA advisory panel. European regulators debated the same question and concluded that Gattex provided a meaningful clinical benefit for SBS patients.
Weaning off parenteral nutrition entirely is the best outcome for SBS patients. To date, 8% of Gattex-treated patients have achieved this goal. [None of the placebo patients have done so.] These patients were treated with Gattex for one year or more.
The FDA drug approval decision date for Gattex is Dec. 28.
--Written by Adam Feuerstein in Boston.
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