for people ages 18 years and up (full criteria)
at San Diego, California and other locations
study started
estimated completion



The purpose of this study is to evaluate the clinical efficacy, safety, and tolerability of IONIS-PKK-LRx in participants with hereditary angioedema (HAE) type 1 (HAE-1), HAE type 2 (HAE-2), or HAE with normal C1-inhibitor (C1-INH) and to evaluate the effect of IONIS-PKK-LRx on plasma prekallikrein (PKK) and other relevant biomarkers.

Official Title

A Randomized, Double-Blind, Placebo-Controlled, Phase 2a Study to Assess the Clinical Efficacy of ISIS 721744, a Second-Generation Ligand-Conjugated Antisense Inhibitor of Prekallikrein, in Patients With Hereditary Angioedema


This is a randomized, double-blind, placebo-controlled, study in up 24 participants and will be conducted concurrently in 2 parts (Part A and Part B); participants will be allocated into Part A or Part B according to type of HAE (i.e., either HAE-1/HAE-2 in Part A or HAE-nC1-INH in Part B). Part A will be randomized, double-blind, and placebo-controlled; and Part B will be open-label. The length of participation in the study will be approximately 8 months, which includes an up to 8-week screening period, a 12-week treatment period, and a 13-week post-treatment period.


Hereditary Angioedema IONIS PKK-LRx Angioedema Angioedemas, Hereditary IONIS-PKK-LRx


You can join if…

Open to people ages 18 years and up

  • Documented diagnosis of HAE-1/HAE-2 (for inclusion in Part A) or HAE-nC1-INH (for inclusion in Part B)
  • Participants must experience a minimum of 2 HAE attacks (assessed by the Angioedema Activity Score [AAS] and confirmed by the investigator) during the screening period
  • Access to, and the ability to use, ≥ 1 acute medication(s) to treat angioedema attacks

You CAN'T join if...

  • Anticipated use of short-term prophylaxis for angioedema attacks for a pre-planned procedure during the screening or study periods
  • Concurrent diagnosis of any other type of recurrent angioedema, including acquired or idiopathic angioedema
  • Known history of or positive test for human immunodeficiency virus (HIV), hepatitis C, or chronic hepatitis B
  • Malignancy within 5 years, except for basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix that has been successfully treated
  • Treatment with another investigational drug or biological agent within 1 month or 5 half-lives, whichever is longer, of screening
  • Exposure to any of the following medications:
  • Angiotensin-converting enzyme (ACE) inhibitors or any estrogen-containing medications with systemic absorption (such as oral contraceptive or hormonal replacement therapy) within 4 weeks prior to screening
  • Chronic prophylaxis with lanadelumab within 10 weeks prior to screening
  • Oligonucleotides (including small interfering ribonucleic acid [RNA]) within 4 months of screening (if single dose received) or within 12 months of screening (if multiple doses received)


  • University of California San Diego (UCSD)
    San Diego California 92122 United States
  • AIRE Medical of Los Angeles
    Santa Monica California 90404 United States


in progress, not accepting new patients
Start Date
Completion Date
Ionis Pharmaceuticals, Inc.
Phase 2
Study Type
Last Updated