Hemophilia is a rare disorder affecting about 20,000 individuals in the United States. Due to insufficient blood clotting proteins, or blood clotting factors, the blood does not clot normally. The complications of improper care can be severe. In a Pharmacy Times® Practice Pearls video series, am expert panel provides a thorough understanding and best practices for the treatment of hemophilia.
The panel is comprised of Luigi Brunetti, PharmD, MPH, BCPS, BCGP, associate professor, Rutgers University Ernest Mario School of Pharmacy, and Robert Wood Johnson University Hospital, Somerset, New Jersey, moderates a discussion on best practices for hemophilia treatment. He is joined by Robert F Sidonio, Jr, MD, medical director of Hemophilia, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, and assistant professor of pediatrics, Emory University School of Medicine, Atlanta, Georgia; and Giles W. Slocum, Pharm.D., BCCCP, clinical pharmacy specialist, Emergency Medicine, Rush University Medical Center in Illinois.
Practice Pearl 2: Best practices, treatment costs, and patient factors
In identifying the different treatment options for hemophilia available for prophylaxis, the timing of determining when to use factor VIII concentrate for prophylaxis has undergone a shift.
“We obviously discuss all the emerging therapies, and there are so many of them that are coming in the next few years, including gene therapy,” Sidonio said. “But the standard is still for us to strongly consider factor VIII replacement in these patients. We do have a clinical trial that we're opening soon looking at Hemlibra [emicizumab-kwah] for infants as prophylaxis. The label does have it available for newborns as well. And I know my colleagues have started some patients on that early in their life. But we're trying to collect some of those data uniformly so we can show that it's a pretty reasonable option.”
Slocum noted that factor VIII products are used for acute bleeds for which levels need to increase relatively quickly.
“We haven't really tiptoed into that world of extended half-life or these longer agents quite yet in this patient population with acute bleeds,” he said.
In terms of adverse events encountered with factor VIII products, the panel noted a relatively minimal adverse effect profile.
“It’s up to the patient preference and the rate of infusion of these intravenous [IV] pushes that we use,” Slocum said. “But again, 1 to 2 minutes for most of these products is fine, so that typically is the big thing. Inhibitor production is something I’m sure we’ll address a little bit as well, but that would be an adverse effect potentially of some of these products that we’re infusing. I don’t know if you have others.”
The panel also discussed the use of emicizumab (Hemlibra), which they said should be considered for many patients, especially those with inhibitors.
Sidonio said there’s a tremendous benefit in terms of cost and efficacy with the use of emicizumab, especially for inhibitor patients. For the non-inhibitor patients, he said it becomes challenging since there are many who are doing very well on factor VIII prophylaxis. For standard patients, he said that although the risk of antibodies against Hemlibra is rare, it still is a a potential issue to monitor.
“The big question is, do you start an infant on it, and what is the frequency of the dosing that you would use? Typically, it would be monthly just because of the vial size,” he said. “But then you have this issue about factor VIII exposure. Inhibitor development, as we were talking about before, is developed typically in the first 20 to 30 exposures to factor VIII. And so, a lot of the questions that we have are do we give that factor VIII early and see if they’re going to have that risk for inhibitors? Or do we start them on Hemlibra knowing that they may not hit 20 to 30 exposures until they’re about 10 or 11 years old? And that may be OK because if they develop an inhibitor, it’ll be easier to manage. It may be more costly, and it may not work as well, we just don’t know that question.”
Brunetti said that for patients on activated prothrombin complex concentrate (aPCC), the risk of adverse events need to be monitored closely when transitioning a patient from an aPCC to emicizumab to reduce the risk.
“We do have a little bit more flexibility with this so it does stray from the activated PCC. You'll see anywhere between 1 to 2 weeks. I'm not sure what you do at your HTC [hemophilia treatment center],” Slocum said. “Allowing emicizumab to get to steady state, it takes about that full 28 days. But there is a little bit of a lag effect, so I'm watching both of those pharmacokinetic curves taking place.”
In terms of a risk-benefit comparison for factor VIII concentrate versus emicizumab, Sidonio noted that the Institute for Clinical and Economic Review performed a study that showed a clear benefit with emicizumab with improved efficacy and a cheaper cost.
“It's really important for those patients who start Hemlibra, they're still going to need factor VIII. They're still going to need a few doses at home,” he said. “We were at a meeting recently and one of the patients was on Hemlibra, and he didn't even carry any factor VIII with him to this meeting. Patients quickly forget, because he said, ‘Well, I haven't had any bleeding in a while.’ And I said, ‘Well, that can change any minute.’ And so it's really important that we have our pharmacists and everybody continually educating them and also educating the payers about this because there have been some restrictions as well.