Efficacy and safety of subcutaneous prophylaxis with dalcinonacog alfa in adults with haemophilia B.

AIM: Phase 2b study to assess efficacy, safety, thrombogenicity, immunogenicity and tolerability with 28 days of daily dosing of subcutaneous (SQ) dalcinonacog alfa as prophylaxis for haemophilia B (HB). METHODS: Adult males with a confirmed diagnosis of congenital HB (factor IX [FIX] activity <2%) received daily dalcinonacog alfa 100 IU/kg SQ until day 28. The primary efficacy endpoint was the number of participants who achieved a steady-state FIX activity level ≥12%. Tolerability, thrombogenicity and immunogenicity were study safety endpoints. RESULTS: Of 6 participants who received study drug, one discontinued the study on day 7 due to injection-site reactions (ISR). Of the 5 participants completing the study, FIX activity level exceeded 12% in 3 participants at day 7, increasing to 4 participants on days 14, 21 and 28 and all 5 at day 29. Pharmacokinetic findings (including mean alpha and beta half-life of 5.3 days and 3.9 days, respectively, and mean residence time of 6.2 days) supported prolonged effects. Thrombogenicity markers remained normal throughout prophylactic injections or showed some initial increases followed by decreases with continued dosing. Two participants had anti-drug antibodies to dalcinonacog alfa at study end, none had neutralizing antibody. Two participants had ISR, both resolved. Reports of redness, swelling, tenderness or pain among the first 3 participants prompted dose-splitting for the last 3 participants, leading to fewer ISR. CONCLUSION: Subcutaneous dalcinonacog alfa is effective in raising FIX levels into the mild haemophilia range, comparable to intravenous extended half-life FIX clotting factors.

Subcutaneous engineered factor VIIa marzeptacog alfa (activated) in hemophilia with inhibitors: Phase 2 trial of pharmacokinetics, pharmacodynamics, efficacy, and safety.

BACKGROUND: Marzeptacog alfa (activated) (MarzAA), a novel recombinant activated human factor VII (FVIIa) variant, was developed to provide increased procoagulant activity, subcutaneous (SC) administration, and longer duration of action in people with hemophilia. OBJECTIVES: To investigate if daily SC administration of MarzAA in subjects with inhibitors can provide effective prophylaxis. METHODS: This multicenter, open-label phase 2 trial (NCT03407651) enrolled men with severe congenital hemophilia with an inhibitor. All subjects had a baseline annualized bleeding rate (ABR) of ≥12 events/year. Subjects received a single 18 µg/kg intravenous dose of MarzAA to measure 24-hour pharmacokinetics (PK) and pharmacodynamics (PD), single 30 µg/kg SC dose to measure 48-hour PK/PD, then daily SC 30 µg/kg MarzAA for 50 days. If spontaneous bleeding occurred, the dose was sequentially escalated to 60, 90, or 120 µg/kg, with 50 days at the final effective dose without spontaneous bleeding to proceed to a 30-day follow-up. The primary end point was reduction in ABR. Secondary end points were safety, tolerability, and antidrug antibody (ADA) formation. RESULTS: In the 11 subjects, the mean ABR significantly reduced from 19.8 to 1.6, and the mean proportion of days with bleeding significantly reduced from 12.3% to 0.8%. Of a total of 517 SC doses, six injection site reactions in two subjects were reported. No ADAs were detected. One fatal unrelated serious adverse event occurred: intracerebral hemorrhage due to untreated hypertension. CONCLUSIONS: The data demonstrated that MarzAA was highly efficacious for prophylactic treatment in patients with inhibitors by significantly decreasing bleed frequency and duration of bleeding episodes.