Botulinum Toxin Type A (Btx-A) treatment for Raynaud’s phenomenon (RP) may not be effective for all patients diagnosed with scleroderma, according to researchers.

The study, “The Therapeutic Efficacy of Botulinum Toxin in Treating Scleroderma-Associated Raynaud’s Phenomenon: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial Assessing, was published in the journal Arthritis & Rheumatology.

The Phase 3, randomized, double-blind, placebo-controlled trial (NCT02165111) enrolled 40 patients: 25 with limited scleroderma and 15 with diffuse scleroderma. The goal was to test the effectiveness of Btx-A injections as a treatment for Raynaud’s.

Each trial participant received an injection of Btx-A (50 units in 2.5 mL) in one hand and a placebo injection (with 2.5 mL sterile saline solution) in the other hand. Hands were picked randomly without the knowledge of the participant. Superficial subcutaneous blood-flow-speed was measured after one and four months of the treatment using a noninvasive Laser Doppler Imaging (LDI) system.

Researchers found that blood flow to the hands did not improve significantly in the 40 patients with scleroderma enrolled in the study.

In fact, one month after Btx-A injection, there was even a reduction of the blood flowing to the hands of the participants.

“To our knowledge, this is the first randomized, placebo-controlled, double-blind, clinical trial evaluating Btx-A injections in patients with RP secondary to scleroderma. In contrast to other studies, our study demonstrated a significant decrease in blood flow with Btx-A,” the researchers wrote.