Intradermal injection of onabotulinumtoxinA (Botox, Allergan) is a safe, effective and well-tolerated treatment for primary axillary hyperhidrosis in adolescent patients, according to the findings of a prospective, multicenter Phase 4 study.
St. Louis, Mo. - Intradermal injection of onabotulinumtoxinA (Botox, Allergan) is a safe, effective and well-tolerated treatment for primary axillary hyperhidrosis in adolescent patients, according to the findings of a prospective, multicenter Phase 4 study.
The study enrolled 144 patients, ages 12 to 17 years. Eligible patients received injections of onabotulinumtoxinA 50 units per axilla at an initial treatment session, and retreatments (up to six at a minimum interval of eight weeks) were allowed over the course of one year.
Subjective and objective assessments showed the treatment was efficacious with reasonably durable benefits, and it had an important positive impact on quality of life.
"Primary hyperhidrosis usually has its onset during adolescence, but there are limited published data on treatment in this population," says Dee Anna Glaser, M.D., professor and vice chairman, department of dermatology, Saint Louis University, St. Louis, Mo., and an investigator in the study.
OnabotulinumtoxinA "is already being used by some clinicians for these younger patients, but this study provides documentation that teens tolerate the injections very well and that the treatment is safe and effective," she adds.
"The positive results indicate that (onabotulinumtoxinA) injection is a wonderful treatment option for primary hyperhidrosis in adolescents who have failed conventional first-line topical therapy.
"Clinicians should not be dissuaded by patient age in selecting this treatment when appropriate," Dr. Glaser says.
Eligibility criteria required patients to have a six-month or longer history of primary axillary hyperhidrosis, inadequate response to topical agents, a Hyperhidrosis Disease Severity Scale (HDSS) score of 3 (underarm sweating barely tolerable and frequently interferes with daily activities) or 4 (underarm sweating intolerable and always interferes with daily activities) and spontaneous resting axillary sweat production at room temperature of at least 50 mg.
Patients were seen after four and eight weeks and were followed by telephone contact thereafter to determine duration of response and elicit reports of adverse events.
Participants who reported an HDSS score of 3 or greater were asked to return to the office within two weeks for gravimetric testing. They were retreated if they had 50 mg or greater of spontaneous resting axillary sweat production in each axilla.
Of the 144 enrolled patients, the majority were female (86 percent) and Caucasian (83 percent). A total of 126 patients (87.5 percent) completed the study. The number of treatments administered ranged from one to six. Eighty percent of patients received just one or two treatments, and the average duration of effect for the first two treatments was about four-and-a-half months.
Duration of response
"The duration of response to (onabotulinumtoxinA) in this study suggests adolescent patients may only need to be treated with this agent on average two or three times per year," Dr. Glaser says.
The primary efficacy evaluation was based on percentage of treatment responders defined by criteria relating to the four-point HDSS. Responders needed to demonstrate a two-grade or greater improvement after each of their first two treatment sessions; a two-grade or greater improvement after the first session and a one-grade improvement after the second session if their pretreatment HDSS score had improved to 3; or a two-grade or greater improvement after the first injection and no need for retreatment within 44 weeks. Of the 144 patients, 55 percent were treatment responders.
"The criteria for defining responders were very stringent, and we did see improvement in other measures, particularly in quality of life measures, even in patients who did not meet the responder definition. This was especially true with the quality of life measures," Dr. Glaser says.
Analyses of changes in HDSS scores for the first three treatment sessions showed statistically significant improvements were achieved consistently at four and eight weeks postinjection.
By four weeks after the second treatment session, almost two-thirds of the treated patients had an HDSS score of 1 (underarm sweating is never noticeable and never interferes with my daily function).
Results from gravimetric measurement of spontaneous resting axillary sweat production showed statistically significant reductions.
After each of the first two treatments, sweat production was reduced by an average of about 85 percent at four weeks and about 80 percent at eight weeks.
At four weeks after each of the first three treatment sessions, more than 90 percent of patients achieved a decrease in sweat production of at least 50 percent, and more than half achieved a 90 percent or greater reduction.
Quality of life
Quality of life impact was assessed using the Children’s Hyperhidrosis Impact Questionnaire and the Children’s Dermatology Life Quality Index. The results showed significant improvements were achieved in total scores and subscale domains at week 4, and they were maintained at week 8.
"Hyperhidrosis can have a significant detrimental quality of life impact, especially in teens, and it was remarkable to see how the patients’ perceived quality of life and self-esteem improved dramatically with effective treatment.
"The results showed the study participants were able to function better and participate more fully and more comfortably in school, sports and social situations, all of the things that are so important for normal psychosocial and emotional development while growing up," Dr. Glaser says.
No patients discontinued treatment because of an adverse event, and only eight (5.6 percent) patients had a treatment-related adverse event. Fewer than 3 percent of patients reported an injection-site related adverse event.
No patients developed neutralizing antibodies to onabotulinumtoxinA.
Disclosure: Dr. Glaser is a consultant for Allergan.