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ARTICLE | Clinical News

STX209: Phase IIb data

May 6, 2013 7:00 AM UTC

The double-blind, U.S. Phase IIb Study 209AS208 in 150 patients ages 5 to 21 years with ASD showed that oral STX209 for 12 weeks missed the primary endpoint of reducing patient-rated ABC-LSW subscale scores from baseline to week 8 vs. placebo (5.3 vs. 6.1 points, p=0.477). STX209 did meet the secondary endpoint of reducing CGI-S scores vs. placebo (0.7 vs. 0.3 points, p=0.009), but missed the secondary endpoints of improving CGI-I (3.1 vs. 3.3 points, p=0.305) and Vineland-II Socialization scale scores, a psycho-educational measure of day-to-day social function, vs. placebo (4.4 vs. 2 points, p=0.152). A post hoc analysis of 97 patients whose Vineland analysis was completed by the same clinician and caregiver showed that STX209 significantly improved Vineland-II Socialization scale scores vs. placebo (7.1 vs. 1.8 points, p=0.006). Additionally, Seaside said that subgroup analyses indicated that improvement in Vineland scores was "notably larger" in patients with an IQ>=70. STX209 was generally well tolerated. STX209 was titrated over 4 weeks to a maximum of thrice-daily 10 (age 5-11 years) or 15 mg (age 12-21 years), with fixed dosing for the subsequent 8 weeks. Data were presented at the International Meeting for Autism Research in San Sebastian. Seaside said it plans to confirm the results by initiating another controlled trial of STX209 in patients with ASD. The primary endpoint will be Vineland-II Socialization scale scores. ...