On June 28, 2016, the National Hemophilia Foundation’s Medical and Scientific Advisory Committee (MASAC) issued a recommendation following the published results of the聽Survey of Inhibitors in Plasma Products Exposed Toddler (SIPPET)聽The SIPPET study was published in the聽New England Journal Of Medicine (NEJM)聽in May 2016. The full text of the SIPPET study is available for a fee to the NEJM.

MASAC’s recommendation consists of five (5) points:

“Based on currently available evidence, MASAC makes the following recommendations:

1. Individuals with greater than 50 exposure days to any recombinant product (i.e. Previously Treated Patients or PTPs) should consider remaining on their current product, since multiple clinical studies have shown that their risk for inhibitor development with any FVIII product is markedly diminished after 50 EDs.

2. Individuals with more than zero and less than 50 exposure days should consider staying on their current recombinant FVIII product, since the differences between SIPPET and numerous other studies may not warrant switching patients who have already initiated a treatment regimen.

3. Newly diagnosed individuals and their caregivers should consider the new data from the SIPPET study in the context of all the accumulated data on inhibitor formation in PUPs and the pathogen safety risk/benefit of the two product classes and consider the following options:

聽聽聽聽 a. Initiate therapy with a pdFVIII/VWF product in all PUPs.

聽聽聽聽 b. Initiate therapy with a rFVIII product as previously recommended by MASAC (6).

聽聽聽聽 c. Initiate therapy with a newer rFVIII product.

4. Regardless of which option is chosen, all PUPs should be enrolled in the ATHN data collection system or a clinical trial to assess outcomes.

5. For all classes of treatment products, the risk for inhibitor formation in PUPs is unacceptably high. All efforts by government, HTCs, patient advocates, and industry should be directed at reducing the risk of inhibitor formation.”

Read the full MASAC recommendation here.

HFA encourages youto聽have an active role in your own health care聽andto聽speak with your doctors聽regularly聽on questions of treatment therapy.



  • Inhibitors聽are antibodies that the immune system develops in response to a clotting factor product used to treat a person with hemophilia.
  • In the SIPPET study, previously-untreated patients (PUPs)were patients under the age of six-years old with severe hemophilia A who had never received factor VIII concentrates before. 250+ PUPs from 14 countries and across five continents were studied.
  • In the SIPPET study, investigators found that in a randomized study, when previously-untreated patients (PUPs) were treated with recombinant factor VIII, there was an 87% higher incidence of inhibitor development than when treated with plasma-derived factor VIII.
  • Donna DiMichele, MD of the聽National Institutes of Health聽(NIH)聽wrote in an聽editorial in the NEJM entitled聽Hemophilia Therapy 鈥 Navigating Speed Bumps on the Innovation Highway鈥that this new data must be integrated when making product decisions for children with severe hemophilia A.


Given the importance of this study, and the implications that it could have for PUPs, HFA has taken the following steps:

  1. We are consulting with our Medical Advisory Committee to disseminate available information to our community.
  2. After the release of the abstract in December 2015, we formally reached out to the聽Medical and Scientific Advisory Council (MASAC)聽of the National Hemophilia Foundation (NHF) to request that they conduct a full review of this study when it became available.
  3. We requested that MASAC consider the temporary suspension of recommendations (or portions thereof) that state any preference for recombinant factor products until the results of the full SIPPET study could be reviewed.
  4. We have provided three (3) previous updates as information has become available so that patients can discuss their treatment options with their medical provider to make decisions.


While SIPPET focused on previously untreated toddler patients, HFA encourages聽all patients聽to maintain an active role in their health care.

  1. Ask Questions:聽Talk to your doctor about this study, your risk for forming an inhibitor, and about the overall care you聽receive. Because聽every patient with hemophilia is at risk of forming an inhibitor, regardless of therapy product,聽the Centers for Disease Control encourages each patient to be tested annually for one.
  2. Be Involved:聽Recognize that you play a vital 聽role in your health care.聽You have the right聽to ask questions, make requests, and learn about all your options.
  3. Take Action:Learn more about this study, and share it with your friends and family.

HFA asks every member of the bleeding disorders community to join us as we advocate every day for safe treatments.聽We聽will continue to provide聽updates聽to the community as we learn more.Together, we are resilient.

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