Results of a Phase III clinical study using botulinum toxin type A to treat primary axillary hyperhidrosis, or excessive underarm sweating, suggests that botulinum toxin type A is a safe and effective treatment for hyperhidrosis. The results were announced at the 2004 American Academy of Dermatology (AAD) annual meeting by Dr. Dee Anna Glaser, Vice Chairman of the Department of Dermatology at Saint Louis University School of Medicine, a lead investigator for the trials. "Most people don't realize that hyperhidrosis is an extremely debilitating chronic condition that affects as many as eight million people in the U.S.," said Dr. Glaser. "As such, the results of this 52-week study using botulinum toxin type A treatment are very exciting because they mean that we are that much closer to having the first truly effective, non-surgical treatment available to meet the needs of patients who suffer from primary axillary hyperhidrosis."
The study - funded by Allergan Inc. - found that four weeks after treatment with botulinum toxin type A (administered intradermally), 75 percent of patients receiving botulinum toxin type A vs. 25 percent on placebo achieved at least a 2-point improvement from baseline on the Hyperhidrosis Severity Scale (HDSS), a 4-point scale. Quantity of sweat production in was also significantly decreased.
"The Hyperhidrosis Severity Scale is an important new tool that physicians can use to identify hyperhidrosis patients who are in need of medical treatment, as well as to assess treatment results over time," explains Dr. Glaser. "It is our hope that physicians will begin to use this valid and reliable scale to quickly and accurately diagnose patients with hyperhidrosis who otherwise might not seek treatment."
The study also assessed the specific effects of primary axillary hyperhidrosis on patients' daily lives at study entry (prior to receiving treatment) and again four weeks after receiving his/her study treatment. It found that hyperhidrosis results in substantial occupational, psychological and physical impairment for the patient, and that botulinum toxin type A treatment markedly improved patients' quality of life as soon as four weeks after initial treatment.
"People who suffer from hyperhidrosis have a very hard time leading a normal life," said Dr. Glaser. "While there is a general misperception that hyperhidrosis is merely a disturbing hygienic issue, the condition should be taken seriously as it could lead to isolation and depression. It is important that physicians are made aware of hyperhidrosis and available treatment options to ensure patients receive proper diagnosis and are not just sent away with instructions to buy a stronger anti-perspirant."
Following screening, 322 patients were randomized to one of three treatment groups (50 units of botulinum toxin type A per underarm, 75 units of botulinum toxin type A per underam or placebo) and were evaluated at one week after treatment and every four weeks thereafter. The primary efficacy evaluation was patient assessment of hyperhidrosis severity using the Hyperhidrosis Disease Severity Scale (HDSS).
Four weeks after treatment session one, the following results were observed:
- 75 percent of patients in each botulinum toxin type A group and 25 percent of placebo patients achieved at least a two-grade improvement from baseline on the HDSS;
- 43 percent of patients treated with botulinum toxin type A required only one treatment for the entire one-year study period, versus 12 percent on placebo;
- Mean sweat production was significantly decreased in both botulinum toxin type A groups four weeks after their initial treatment (82 percent, 87 percent and 22 percent decreases in the 50U, 75U and placebo groups respectively);
- Upon completion of the study, 85 percent and 84 percent of patients treated with 50U and 75U of botulinum toxin type A respectively reported that they were much more satisfied with the current study treatment than with previous treatments, versus 20 percent of patients on placebo;
- There was no difference between the 50U and 75U groups in terms of measured efficacy endpoints.
No serious treatment-related adverse events were reported. The most frequently reported treatment-related adverse events (>5 percent in any treatment group) were injection site pain, injection site hemorrhage and non-axillary sweating. The incidence of these events was not significantly different between groups.
