ATLANTA—Updated results from the HAVEN 2 trial have shown that emicizumab prophylaxis can reduce bleeds in children with hemophilia A and factor VIII inhibitors.
Sixty-five percent of all patients enrolled in HAVEN 2 had no bleeds while on emicizumab, and 95% had no treated bleeds.
Among patients who had been on emicizumab for at least 12 weeks, 35% had no bleeds, and 87% had no treated bleeds.
The most common adverse events (AEs) in this trial were viral upper respiratory tract infections and injection site reactions.
Guy Young, MD, of Children’s Hospital Los Angeles in California, presented these results at the 2017 ASH Annual Meeting (abstract 85). The trial was sponsored by Hoffmann-La Roche.
HAVEN 2 enrolled 60 patients, ages 1 to 17, who had hemophilia A and inhibitors. Most patients (95%) had severe hemophilia, 3.3% (n=2) had mild disease, and 1.7% (n=1) had moderate disease.
Nearly a quarter of patients (73.3%) had previously received prophylaxis, and 26.7% had previously received episodic treatment.
The median number of bleeds in the previous 24 weeks was 6.0 (range, 0-155), and 38.3% of patients had target joints.
Patients received emicizumab prophylaxis at 3 mg/kg/week for 4 weeks and 1.5 mg/kg/week thereafter. The median observation time was 9 weeks (range, 1.6 to 41.6 weeks).
The efficacy analysis included 57 patients who were younger than 12. The 3 older patients were only included in the safety analysis.
Of the 57 patients, 64.9% had 0 bleeds, 94.7% had 0 treated bleeds, and 98.2% had 0 treated spontaneous bleeds and 0 treated joint bleeds. None of the patients had treated target joint bleeds.
There were a total of 65 bleeds in 20 patients. Eight were joint bleeds, 2 were muscle bleeds, and the rest were classified as “other.” Of the 55 “other’’ bleeds, 26 (40.0%) were spontaneous, 36 (55.4%) were traumatic, and 3 (4.6%) were due to a procedure/surgery.
A subset of 23 patients received emicizumab for at least 12 weeks. They had a median treatment duration of 38.1 weeks (range, 12.7 to 41.6 weeks).
Of these patients, 34.8% had 0 bleeds, 87.0% had 0 treated bleeds, and 95.7% had 0 treated spontaneous bleeds and 0 treated joint bleeds. There were a total of 41 bleeds in 15 of these patients. Three bleeds (joint, muscle, and hip) were treated.
The median annualized bleeding rate (ABR) for the 23 patients was 1.5 for all bleeds and 0.0 for all types of treated bleeds.
There were 13 patients who had participated in a non-interventional study prior to enrolling in HAVEN 2, so these patients could serve as their own controls. The patients had an overall reduction in ABR of 99% with emicizumab.
All 60 patients were evaluated for safety. Forty patients had a total of 201 AEs. The most common AEs were viral upper respiratory tract infection (16.7%) and injection site reactions (16.7%)
There were 7 serious AEs in 6 patients—muscle hemorrhage (n=2), eye pain, catheter site injection, device-related infection, mouth hemorrhage, and appendicitis. None of these events were considered treatment-related.
There were no thromboembolic or thrombotic microangiopathy events, and none of the patients tested positive for anti-drug antibodies.
“The safety profile of emicizumab was favorable and well-tolerated,” Dr Young said. “And these updated results from the HAVEN 2 study confirm our prior efficacy results, presented at ISTH, that emicizumab successfully prevents or reduces bleeds.”