Clinical response and symptomatic remission in short- and long-term trials of lisdexamfetamine dimesylate in adults with attention-deficit/hyperactivity disorder.
BACKGROUND
Despite the overall high degree of response to pharmacotherapy, consensus is lacking on how to judge clinical response or define optimal treatment/remission when treating adults with attention-deficit/hyperactivity disorder (ADHD). This study examined clinical response and symptomatic remission in analyses of 2 studies of lisdexamfetamine dimesylate (LDX) in adults with ADHD.


METHODS
In a 4-week, double-blind, forced-dose trial, adults with ADHD were randomized to LDX 30, 50, and 70 mg/day (mg/d) or placebo. In a second, open-label, follow-up trial, adults entering from the 4-week study were titrated to an "optimal" LDX dose (30 mg/d [n=44], 50 mg/d [n=112], and 70 mg/d [n=171]) over 4 weeks, and maintained for 11 additional months. The ADHD Rating Scale IV (ADHD-RS-IV) with adult prompts and the Clinical Global Impressions-Improvement (CGI-I) scale assessed efficacy. Clinical response was defined, post hoc, as ≥30% reduction from baseline in ADHD-RS-IV and CGI-I rating of 1 or 2; symptomatic remission was defined as ADHD-RS-IV total score ≤18. Log rank analysis examined overall significance among the treatment groups in time to response or remission.


RESULTS
Four hundred and fourteen participants in the 4-week study and 345 in the open-label, extension study were included in the efficacy populations. All LDX groups improved by ADHD-RS-IV and CGI-I scores in both studies. In the 4-week study (n=414), 69.3% responded and 45.5% achieved remission with LDX (all doses); 37.1% responded and 16.1% achieved remission with placebo; time (95% CI) to median clinical response (all LDX doses) was 15.0 (15.0, 17.0) days and to remission was 31.0 (28.0, 37.0) days (P<.0001 overall). In the open-label study, with LDX (all doses), 313 (95.7%) and 278 (85.0%) of 327 participants with evaluable maintenance-phase data met criteria for response and remission, respectively. Of participants who completed dose optimization, 75.2% remained responders and 65.7% remained in remission in the 12-month study. Overall, 285 (82.6%) and 227 (65.8%) of 345 participants were responders and remitters, respectively, at their final visits.


CONCLUSIONS
In the long-term study, with open-label, dose-optimized LDX treatment, most adults with ADHD achieved clinical response and/or symptomatic remission; almost two-thirds maintained symptomatic remission over the remaining 11 months.


BACKGROUND
Clinical Trial Numbers: NCT00334880 and NCT01070394CLINICAL TRIAL REGISTRY: clinicaltrials.gov.
St Charles Psychiatric Associates/Midwest Research, 4801 Weldon Spring Pkwy, Suite 300, St Charles, MO, USA. greg@mattingly.com
Greg W
GW
Mattingly
Richard H
RH
Weisler
Joel
J
Young
Ben
B
Adeyi
Bryan
B
Dirks
Thomas
T
Babcock
Robert
R
Lasser
Brian
B
Scheckner
David W
DW
Goodman
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D003913:Dextroamphetamine / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D000069478:Lisdexamfetamine Dimesylate; D008297:Male; D011569:Psychiatric Status Rating Scales; D012074:Remission Induction / Q000379:methods; D016896:Treatment Outcome
D000697:Central Nervous System Stimulants; D000069478:Lisdexamfetamine Dimesylate; D003913:Dextroamphetamine