Dr. Callaghan Talks About HAVEN Study Investigating Emicizumab in Patients with Hemophilia A

During the all-virtual 62nd ASH Annual Meeting & Exposition, Michael U. Callaghan, MD, Associate Professor of Pediatrics, Division of Pediatric Hematology/Oncology, Children’s Hospital of Michigan, presented the results of a study on the safety and efficacy of emicizumab in patients with hemophilia A with or without FVIII inhibitors.

Dr. Callaghan talked further about the results of the study in an interview with DocWire News.

DocWire News: What prompted you to undertake this study?

Dr. Callaghan: After the studies subjects continued with certain portions of the study to maintain access to the medication until it became commercially available.  Data continued to be collected and the data were collected the same way across the HAVEN Trials which allowed for analysis of a much larger group of patients over a longer period of time.

DocWire News: What are the key takeaways from the study?

Dr. Callaghan: No new or unexpected safety signals with longer term follow-up and almost 1,000 patient-years on emicizumab. Bleed rates remained low and, in fact, were numerically lower over time converging on a mean treated bleed rate below 1 bleed per year with about 90% of subjects not experiencing bleeds over a given 24-week time period. This was true regardless of age or inhibitor status. Almost all target joints resolved.

DocWire News: Did any of the study’s findings surprise you?

Dr. Callaghan: The results were in line with my clinical experience. Most of my patients have little or no bleeding regardless of age or inhibitor status. As they are on emicizumab, joints that were previously prone to bleeding improve and the patients become more confident in their treatment. I think both of these factors contribute to the lower mean ABRs (annualized bleeding rate) at later time points we see in this study.

DocWire News: What limitations did the study have?

Dr. Callaghan: This was a post-hoc analysis.  The study wasn’t designed to measure changes in bleed rates over time, there is also no control group for the longer term data.  While I think the results are clear and in line with my clinical experience – these are post-hoc analyses and uncontrolled observation.

DocWire News: Do you have any future research plans pertaining to this area?

Dr. Callaghan: Emicizumab has made a considerable change in practice and is rapidly being adopted as standard of care in inhibitor patients and non-inhibitor patients.  The changes this brings give many opportunities for studies.  I am involved in planned studies looking at ITI with Emicizumab, Emicizumab in previously untreated patients, and optimal treatment of breakthrough bleeding.

DocWire News: Any information not addressed by the previous questions that you would like to share?

Dr. Callaghan: I think this is likely the largest prospective set of data collected for clinical trials of a new therapy for hemophilia and continues to demonstrate lower bleed rates and more patients without bleeds than is possible with other available treatments.

An abstract of Dr. Callaghan’s study, Safety and Efficacy of Emicizumab in Persons with Hemophilia A With or Without FVIII Inhibitors: Pooled Data from Four Phase III Studies (HAVEN 1–4), can be found here.