SAN DIEGO (FRONTLINE MEDICAL NEWS)Atomoxetine was linked to “gradual, modest” improvements in 8 of 10 children with attention-deficit/hyperactivity disorder, according to a pooled analysis of seven clinical trials.

A smaller group of children who showed “early, robust” improvement on atomoxetine had severe symptoms at baseline and tended not to have been treated with stimulants, reported Linda A. Wietecha, a clinical research scientist at Eli Lilly in Indianapolis.

Atomoxetine is a selective noradrenergic reuptake inhibitor that is used as a first-line treatment for ADHD in some patients , including those with comorbid anxiety, substance abuse disorders, or tics. A past study reported a generally bimodal distribution of treatment response, in which 47% of children markedly improved on the medication, 40% did not respond, and only 13% showed a minimal improvement, Ms. Wietecha said at the annual meeting of the American Association of Child and Adolescent Psychiatry.

To further explore patterns of atomoxetine response, she and her associates used the investigator-rated ADHD Rating Scale to analyze 925 patients in seven double-blind, placebo-controlled clinical trials conducted between 2002 and 2009. Almost three-quarters (73%) of patients were male, and 74% had been diagnosed with the combined subtype of ADHD, meaning they had both inattentive and hyperactive or impulsive symptoms.

The pooled analysis showed that 27% of patients had moderate to severe total baseline scores and modest improvement on atomoxetine, 55% had severe total baseline scores and modest responses, and 18% had severe total baseline scores and robust responses. The results were similar when the investigators looked at the inattention subscale, except that 34% of patients had robust improvement with severe baseline scores. These patients were more likely than patients in the other categories to be slow metabolizers of atomoxetine, Ms. Wietecha added.

The analysis also showed that modest responders were more likely to have received stimulants (58%) than were robust responders (45%). And patients with the inattentive ADHD subtype trended toward moderate to severe baseline scores and modest treatment responses.

Eli Lilly funded the study and is the maker of atomoxetine. Ms. Wietecha and three study coauthors are employees and shareholders of Eli Lilly or its subsidiaries.