New England Journal of Medicine (NEJM) has published results from the COMPACT study, a pivotal Phase III study evaluating the safety and efficacy of CSL830 (a novel, investigational, self-administered, subcutaneous C1-Esterase Inhibitor [C1-INH] Human replacement therapy) from CSL Behring.

The study met its primary efficacy endpoint, significantly reducing the time-normalized number of HAE attacks. In addition, the study met its secondary endpoints, including the responder rate (patients who had at least a 50% reduction in their attack rate) and the number of rescue medication uses. If approved by the FDA, CSL830 would be the first and only subcutaneous preventative therapy for HAE.

“Subcutaneous C1-INH, as demonstrated in the COMPACT study, addresses an unmet need for patients and has the potential to change the treatment paradigm by adding a new option to prevent HAE attacks with a subcutaneous therapy,” said Bruce Zuraw, M.D., of the University of California San Diego School of Medicine, Director of the US HAEA Angioedema Center at UC San Diego, and chairman of the steering committee of the study.

The NEJM paper provides detailed data on the Phase III randomized efficacy study which evaluated type I & type II HAE patients during two 16-week treatment periods. The study looked at the number of attacks experienced by a patient given CSL830 prophylactically and the number of times HAE rescue medication was needed; both were reduced. Depending on the administered dose, HAE attack rates were reduced by a median of 89% and 95% (for the 40 IU/kg and 60 IU/kg dose, respectively). Additionally, 40% of patients on the higher dose were completely free of attacks, and patients, in general, experienced fewer and milder HAE symptoms overall. No patients on 60 IU/kg experienced a laryngeal attack within the study period.

“The study not only demonstrates very robust and dose-dependent efficacy, but also that the subcutaneous self-injection could be managed by all patients and was well tolerated,” said Hilary Longhurst, M.D., of Barts Health NHS Trust, London, United Kingdom, first author of the manuscript and member of the steering committee.

“Despite the strides that have been taken to provide current treatment options, there still remains a need for new therapies that prevent symptoms of this debilitating and potentially life-threatening disease,” added Andrew Cuthbertson, M.D., Chief Scientific Officer and R&D Director, CSL Limited. “These study results demonstrate the promise of CSL830 and its potential to significantly change the lives of people living with HAE by reliably preventing attacks with a self-administered subcutaneous therapy. CSL Behring thanks all of the patients who participated in this study for their courage and collaboration. Patient and investigating physician partnerships make clinical programs like COMPACT possible and progress could not be made without them.”

(Source: CSL Behring)