Efficacy of Oral Acetylsalicylic Acid versus Placebo Added to Topical Diclofenac for Thrombotic Episodes in Superficial Venous Malformations in Children Aged 6 to 17 Years

The primary objective is to evaluate the efficacy of oral acetylsalicylic acid compared to placebo, administered alongside a topical non-steroidal anti-inflammatory drug, in managing pain associated with superficial venous thrombosis in pediatric patients with venous malformations. 5, 3

Secondary objectives include:

• Reduction in analgesic consumption
• Assessment of quality of life
• Evaluation of tolerability
• Impact on coagulation markers
• Effect on sleep quality
• Evaluation of functional impotence related to the malformation

The sponsor did not provide information regarding the total number of participants. The study population consists of pediatric patients experiencing thrombotic episodes in superficial venous malformations. Eligible participants include both males and females aged 6 to 17 years with a body weight of at least 20 kg. Inclusion requires imaging confirmation via magnetic resonance imaging, computed tomography, or Doppler ultrasound of isolated or combined malformations, specifically demonstrating phleboliths as evidence of prior superficial venous thrombosis. The subjects must have experienced at least two acute thrombotic events within the previous 12 months. Additional requirements involve the provision of written consent by legal representatives and, for females of childbearing age, the use of highly effective contraception.

This controlled randomized, double-blind, cross-over, multicenter trial is designed to evaluate the efficacy of oral acetylsalicylic acid compared to a placebo in managing pain associated with thrombotic episodes in children aged 6 to 17 years with superficial venous malformations. The investigation incorporates the use of a local non-steroidal anti-inflammatory drug as background therapy. The methodology involves a treatment period lasting between 3 and 14 days. Following the initial screening to confirm inclusion criteria via imaging such as magnetic resonance imaging or Doppler ultrasound, participants will undergo the study protocol. Secondary outcomes include monitoring analgesic consumption, quality of life through specific indices, safety via adverse events monitoring, and assessment of coagulation markers. Functional impairment is measured using a visual analog scale. The total duration of the study recruitment and completion is estimated to extend from February 2026 to February 2030.

The experimental medication consists of acetylsalicylic acid administered as a 320 mg tablet. The total daily dose is 1920 mg, delivered via the oral route.

A placebo containing calcium hydrogen phosphate dihydrate is used for comparison. This substance is administered at a dose of 1920 mg through the oral route.

Background therapy involves diclofenac diethylamine, provided in a 1% gel form. The application is for cutaneous use at a dose of 2 g.

The primary efficacy endpoint is the evaluation of pain relief following the administration of acetylsalicylic acid in combination with a local non-steroidal anti-inflammatory drug compared to a placebo and local non-steroidal anti-inflammatory drug over a period of 3 to 14 days. Secondary endpoints include the cumulative consumption of tier 1 and 2 analgesics over 14 days as an indirect measure of treatment efficacy. The impact on the quality of life will be assessed using the Children-Quality of Life Index and the CLFMQol at baseline and after each attack. Additionally, coagulation markers, including complete blood count, prothrombin time, activated partial thromboplastin time, plasma fibrinogen, and D-dimers, will be measured during attacks of superficial venous thrombosis. The impact of the malformation on sleep quality will be monitored using the Fast Score SLEEP VASC once daily for 14 days. Functional impairment will be assessed daily using a visual analog scale at baseline and after each follow-up.