Reply to Seddon, Schaaf, and Hesseling.

To the Editor—We agree with Drs Seddon, Schaaf, and Hesseling that research focused on optimizing the use of second-line drugs for children with drug-resistant tuberculosis is urgently needed [1]. As the authors state, the disease burden and spectrum are different in young children and adults; pediatric pharmacokinetic and efficacy data for second-line drugs are limited; and formulation and toxicity issues exist that are unique to young children. Indeed, this topic is of such importance and complexity that we feel that it merits its own full-length article to be adequately addressed. A review of the existing evidence for use of second line drugs in pediatric populations which also identifies high-priority topics and suggests methods of inquiry and models for research of unique or special importance to children with drug-resistant tuberculosis would be of extreme value for the tuberculosis research community and to clinicians who care for children with tuberculosis. We regret having omitted mention of pediatric patients in our review and would direct readers to a recently-published review of pediatric use of second-line tuberculosis drugs authored by Drs Seddon, Schaaf, and Hesseling and their colleagues [2].