6207: Topical Anti-angiogenic Therapy for Telangiectasia in HHT: Proof of Concept



Hereditary Hemorrhagic Telangiectasia (HHT) is a condition that causes abnormal blood vessels. The small abnormal blood vessels in HHT are called telangiectasia and the larger ones are called arteriovenous malformations (AVM).

There is a type of therapy called anti-angiogenic therapy that limits the growth of new blood vessels. Apo-Timop (Timolol Maleate Ophthalmic Solution USP 0.5%) is a medication used for this type of therapy.

The study researchers think that anti-angiogenic therapy, such as Timolol Maleate Ophthalmic Solution USP 0.5%, may lead to the shrinking of telangiectasia in people with HHT. The researchers hope that this study will show that putting Timolol Maleate Ophthalmic Solution USP 0.5% on telangiectasia will lead telangiectasia to shrink. Also, the researchers hope that this finding might lead to the development and further study of anti-angiogenic therapies to help improve the lives of individuals with abnormal blood vessels.

About this Study

This is a pilot study that will include 10 participants from St. Michael’s Hospital in Toronto, Canada who have HHT and at least 5 telangiectasia on their hands. Individuals participating in this study will be seen 7 times within a 12 week period at St. Michael’s Hospital.

For each participant, 5 telangiectasia on his/her hands will be numbered (1-5) and then randomly assigned to the following procedures:

  • Biopsy
  • Biopsy and Topical timolol maleate 0.5% drops (anti-angiogenic therapy)
  • Topical timolol maleate 0.5% drops only (anti-angiogenic therapy) – 2 telangiectasia will be assigned to this procedure
  • Placebo saline drops (drops without any anti-angiogenic therapy)

The drops will be applied to the assigned telangiectasia on each participant’s hands, twice daily for 12 weeks (84 days) or until the telangiectasia disappear.

Targeted Enrollment

To be eligible to participate, you must:

  • Have a definite clinical or genetic diagnosis of HHT.
  • Have a known ENG or ALK1 mutation (personal or familial).
  • Be 18 years of age or older.
  • Have at least 5 typical (round/ovoid, not spider or linear) cutaneous telangiectasia (size range 2-5mm) on hands (not including lesions on over inter-phalangeal joints) or face.

You are not eligible to participate if you:

  • Have asthma, severe COPD, sinus bradycardia, 2nd or 3rd degree AV block, overt heart failure, hypotension, allergy/reaction to timolol).
  • Are currently treated with beta-blocker in pill form.
  • Are currently participating in another treatment trial for HHT.
  • Are currently pregnant or breastfeeding.

How to participate:

In order to participate, you must personally contact the study coordinator of any of the participating institutions by phone or by email. Please use the information below to inquire about participation:


St. Michael’s Hospital, Toronto
Dewi Clark, Study Coordinator
416-864-6060 extension 2887
E-mail: clarkde@smh.ca