Hemlibra for Mild, Moderate Hem A Supported by HAVEN 6 Study Data

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Most people with moderate or mild hemophilia A who received preventive treatment with Hemlibra (emicizumab) in the HAVEN 6 clinical trial had no bleeds requiring treatment over a median follow-up of over a year, new data show.

The findings were presented at the 30th International Society on Thrombosis and Haemostasis (ISTH) Annual Congress, held earlier this month in London, U.K.

Based on these data, Genentech, which markets Hemlibra, is planning to submit an application asking the European Medicines Agency to expand Hemlibra’s approval in the EU.

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Currently, Hemlibra is approved only for severe hemophilia A in the EU, though in the U.S. and elsewhere it is approved for all hemophilia A patients. The therapy, given via injection under the skin, works by mimicking the activity of the clotting protein that is lacking or is dysfunctional in hemophilia A, called factor VIII (FVIII).

“The data presented at ISTH this year underscore Genentech’s commitment to addressing gaps in care for hemophilia A, thereby ensuring that broader populations can potentially benefit from Hemlibra,” Levi Garraway, MD, PhD, chief medical officer and head of global product development at Genentech, said in a press release.

“We are proud that Hemlibra continues to redefine the standard of care for more people living with hemophilia A,” he said.

The Phase 3 HAVEN 6 trial (NCT04158648) enrolled 21 people with mild hemophilia A and 51 with moderate disease. Among the 72 participants, three were women and 69 were men. None had FVIII inhibitors, 37 had been on prophylactic, or preventive, replacement therapies before entering the study, and 24 had target joints (joints with frequent bleeds).

Before entering the study, the patients had an estimated average bleeding rate of more than 10 bleeds per year.

All of the participants were treated with Hemlibra — 3 mg/kg once per week for four weeks, followed by either 1.5 mg/kg once weekly, 3 mg/kg every two weeks, or 6 mg/kg every four weeks. They were followed for a median of 55.6 weeks, or just over a year.

Two-thirds of the participants (66.7%) had no bleeds requiring treatment for the duration of follow-up. In addition, 81.9% experienced no spontaneous bleeds requiring treatment, and 88.9% experienced no joint bleeds warranting treatment.

The estimated annual bleeding rate was 2.3 bleeds per year overall, and 0.9 bleeds per year requiring treatment.

The safety profile of Hemlibra in HAVEN 6 was generally consistent with that of previous studies. The most common side effect related to Hemlibra was reactions at the injection site, reported in 16.7% of the participants.

“These data show continued efficacy and a favorable safety profile of [Hemlibra] in people with non-severe [hemophilia A] without FVIII inhibitors who warrant prophylaxis,” the researchers wrote.

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Study Reveals Risk Factors for Future Bleeds in Hemophilia Patients

At the ISTH meeting, Genentech also presented data from CHESS II and CHESS PAEDs, a pair of retrospective studies examining treatment patterns and disease burden in adults (CHESS II) and children (CHESS PAEDs) with hemophilia A.

Results from CHESS II showed that over 90% of adults with mild or moderate hemophilia A were not on routine prophylactic treatment. Among those not on prophylaxis, 84.5% of those with moderate disease and 75% of those with mild disease reported at least one bleed per year. About a third (34.5%) of patients with moderate hemophilia A who were not on prophylaxis reported at least three bleeds per year.

Of the 282 children with moderate hemophilia in CHESS PAEDs, about half (51.8%) were not on routine prophylaxis. Among these patients, 74% experienced at least one bleed per year, and 40.4% had three or more bleeds per year.

“Additional research is warranted to investigate potential reasons for limited use of prophylaxis in these populations,” the researchers wrote.

Another analysis focused on 146 severe hemophilia A patients in CHESS II who were treated with Hemlibra, and results indicated that bleed rates generally decreased after patients started treatment.