This article is part of MPR‘s coverage of the ACAAI 2019 meeting, taking place in Houston, TX. Our staff will report on medical research related to allergies, asthma, and more conducted by experts in the field. Check back regularly for more news from ACAAI 2019.

Data from the open-label extension (OLE) portion of the phase 3 HELP study showed lanadelumab-flyo (Takhzyro; Takeda) continued to prevent hereditary angioedema (HAE) attacks in patients aged ≥12 years over a mean treatment duration of 19.7 months.

The original 26-week, randomized, phase 3 HELP (Hereditary Angioedema Long-Term Prophylaxis) study enrolled 125 patients with HAE aged ≥12 years, of whom 109 rolled over to the ongoing OLE study with an additional 103 eligible non-rollover patients. Patients received lanadelumab 300mg subcutaneous (SC) injection every 2 weeks for up to 924 days (N=212). The primary end point was the long-term safety of lanadelumab; secondary end points included the long-term efficacy of lanadelumab in the prevention of HAE attacks.

Results from the HELP Study OLE demonstrated the safety profile of lanadelumab was consistent with that observed in the original HELP study, with treatment-emergent adverse events (TEAE) occurring in 50% of patients (n=106). In addition, secondary efficacy end points were achieved in the OLE study with an overall reduction of 87% in the mean rate of attacks, a 92.6% reduction in the rate of attacks requiring acute treatment, and an 83.6% reduction in the rate of moderate to severe attacks compared with baseline (N=212). Moreover, an exploratory analysis showed that the overall maximum attack-free period lasted ≥12 months in 58% of patients (n=209) and ≥6 months in 78% of patients (n=209) following the first regular treatment dose.

With regard to safety, TEAEs were mostly mild or moderate in severity occurring in approximately 95% of patients. The most common TEAEs were injection site pain, erythema, and bruising. 

Data from the HELP Study OLE will be presented at the 2019 American College of Allergy, Asthma and Immunology (ACAAI) Annual Meeting in Houston, Texas from November 7-11.

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“While the original HELP Study data has given us a strong understanding of how Takhzyro can prevent HAE attacks, the results of these analyses provide encouraging insight into its potential safety and efficacy over a longer duration,” said Marc A. Riedl, MD, an investigator in the HELP Study OLE and Professor of Medicine and Clinical Director, US Hereditary Angioedema Association Center at the University of California, San Diego. 

Takhzyro is a first-of-its-kind fully human IgG1 monoclonal antibody (mAb) that specifically binds plasma kallikrein and inhibits its proteolytic activity. It is indicated for prophylaxis to prevent attacks of HAE in patients ≥12 years.

The product is supplied as a 300mg/2mL (150mg/mL) strength solution for subcutaneous injection in single-dose vials. 

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