More preventive treatment options needed, researchers say
Prophylactic treatments lacking for those with inhibitors
Prophylactic (preventive) treatment for hemophilia A and B is generally more effective than on-demand treatment in reducing the frequency of bleeding, but the benefit is not as clear in patients who have developed inhibitors that limit how well replacement clotting factors work.
That’s according to real-world data from explorer6 (NCT03741881), a non-interventional study sponsored by Novo Nordisk that ran across 33 countries. The study followed patients with hemophilia A or B, with or without inhibitors, on their usual treatment, for up to 115 weeks (about 2.2 years).
“An unmet need remains among patients receiving [on-demand] treatment and those with inhibitors,” the researchers wrote, calling for effective prophylactic treatment options that can reduce the frequency of bleeding despite the presence of inhibitors.
The study, “Real-World Unmet Needs of Patients With Haemophilia A and Haemophilia B With or Without Inhibitors: End-of-Study Results From the explorer6 Non-Interventional Study,” was published in Haemophilia. Two of its researchers work at Novo Nordisk.
Hemophilia is a disease in which the blood doesn’t clot properly because a clotting factor is either faulty or missing, resulting in excessive bleeding and bruising. In hemophilia A, the faulty or missing clotting factor is factor VIII (FVIII), and in hemophilia B, it is factor IX (FIX).
Preventive treatments not using FVIII, FIX needed, researchers say
Standard treatments, which replace the missing clotting factors, work well for most patients. But there is an unmet need for those who develop inhibitors (neutralizing antibodies) against the delivered clotting factors, the researchers said, calling for treatment options that do not involve the use of FVIII or FIX.
The explorer6 study aimed to collect data from patients with hemophilia A or B, with or without inhibitors. It was a non-interventional study, meaning that patients were on their usual prophylactic or on-demand treatment while data were collected.
The study involved 231 adults and adolescents ages 12 and older. Most (97.8%) had severe hemophilia, while five had mild to moderate hemophilia. There were 138 patients without inhibitors (70 with hemophilia A and 68 with hemophilia B) and 80 with inhibitors (49 with hemophilia A and 31 with hemophilia B).
The mean annualized bleeding rate for treated bleeds, a measure of the number of bleeding episodes that required treatment adjusted to a one-year time window, was higher for patients who were on on-demand treatment than for those who were on prophylactic treatment. However, the difference was not as clear in patients with inhibitors.
Patients with hemophilia A without inhibitors had a mean of 21.5 bleeds per year that required treatment if they were on on-demand treatment and 4.7 bleeds per year if they were on prophylaxis; for those with inhibitors, the mean annualized bleeding rates for treated bleeds were 15.2 for on-demand treatment and 10.3 for prophylaxis.
Similarly, patients with hemophilia B without inhibitors had 10.5 and 2.2 bleeds per year that required treatment if they were on on-demand versus prophylactic treatment, respectively. Patients with hemophilia B with inhibitors had 9.3 and 12.4 bleeds per year if they were on on-demand versus prophylactic treatment, respectively.
Patients are encouraged to stay physically active, “as this has been shown to improve long-term joint, bone and muscle health and promote physical fitness and normal neuromuscular development,” the researchers wrote. However, they added, physical activity can put strain on the joints.
Those on prophylactic treatment had better joint health, shown by lower Hemophilia Joint Health scores, and were more active than those treated on demand. The number of joints affected by bleeding was similar regardless of whether patients received prophylactic or on-demand treatment.
“It is evident that unmet needs, in particular the management of bleeding episodes, joint health and physical activity, remain for patients receiving [on-demand] treatment and patients with inhibitors,” the researchers wrote. “These unmet needs emphasize the necessity of new therapeutic options.”
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