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Infants with hemophilia A who received monoclonal antibody emicizumab experienced few bleeding events and no serious complications, a study suggests.

Emicizumab was approved as a first line therapy for the severe bleeding disorder in 2017 but had mostly been tested in older children and adults.

The study is the first to specifically report on safety and efficacy of the therapy in infants.

Preliminary results from the multi-center, Michigan Medicine-led HAVEN 7 trial were presented at the American Society of Hematology annual meeting in San Diego.

“These are reassuring findings for families of babies with hemophilia A, confirming that this drug is safe and highly effective in preventing all bleeding in infants with this disease,” said lead author Steven Pipe, M.D., professor of pediatrics and pathology at the U-M Medical School and hematologist-oncologist at U-M Health C.S. Mott Children’s Hospital.

The study involved 55 infants, median age of four months, with severe hemophilia A who received subcutaneous injections of the drug weekly for four weeks and then every two weeks for a year.

Researchers plan to follow the patients for an additional seven years.

Before emicizumab’s approval, the standard treatment for severe hemophilia A involved regular intravenous infusions of the clotting factor VIII that’s missing in people with the disease, replacing the protein necessary to control bleeds.

Babies born with hemophilia A, however, cannot usually receive factor VIII infusions because of the challenges and risks of administering the drug to infants, often requiring a central venous access device.

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This previously left limited therapy options for the youngest children with the bleeding disorder, Pipe says, increasing risks of uncontrolled traumatic and spontaneous bleeding, which may damage joints and organs, including bleeding in the brain.

Nearly 30% of adults and older children treated with factor VIII infusions also develop a significant treatment related complication when the immune system forms antibodies against factor VIII.

These antibodies, known as inhibitors, prevent clot formation by destroying the clotting factor before it has a chance to stop the bleeding, making the treatment less effective and increasing risks of breakthrough bleeding episodes. 

Emicizumab was developed as a novel alternative to factor VIII over the last decade. It was first approved for those who had developed factor VIII inhibitors with other treatments and then as the primary prophylactic therapy for hemophilia A, which affects about one in 5,000 male births. 

Pipe says he anticipates seeing greater use of the hemophilia drug in babies as emerging data supports efficacy and safety in even the youngest infants.

“These findings support advancements in treatment for children with hemophilia A,” he said. “The quality of life and overall outcomes for adults with hemophilia largely depends on successful treatment to prevent bleeding during early childhood and formative years.”

Additional authors include: Peter Collins, School of Medicine, Cardiff University, UK; Christophe Dhalluin, Christophe Schmitt, Muriel Buri, Anna Kiialainen, Michaela Lehle and Markus Niggli, all of F. Hoffmann-La Roche Ltd, Switzerland; Gili Kenet, Sheba Medical Center and 5Tel Aviv University, Israel; Víctor Jiménez-Yuste, Hospital Universitario La Paz-IdiPaz, Universidad Autónoma, Spain; Flora Peyvandi, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Italy; Guy Young, Children’s Hospital, California; Johannes Oldenburg, University of Bonn, Germany; Maria Elisa Mancuso, IRCCS Humanitas Research Hospital and Humanitas University, Italy;

Kaan Kavakli, Ege University Faculty of Medicine Children's Hospital, Turkey; Tiffany Chang, Spark Therapeutics, Inc., California; Karin Fijnvandraat, University of Amsterdam, Netherlands

Disclosures: Pipe has served as a consultant to Genetech/Roche on the development of novel therapeutics for hemophilia.

Study cited: “Emicizumab Prophylaxis in Infants with Severe Hemophilia A without Factor VIII Inhibitors: Results from the Primary Analysis of the HAVEN 7 Study.”