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.

Introduction

The rapid clearance of factor IX necessitates frequent intravenous administrations to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration has historically been limited by low bioavailability and potency. Dalcinonacog alfa was developed using a rational design approach to be a subcutaneously administered, next-generation coagulation prophylactic factor IX therapy.

Aim

This study aimed to investigate the pharmacokinetic, pharmacodynamic, and safety profile of dalcinonacog alfa administered subcutaneously in hemophilia B dogs.

Methods

Two hemophilia B dogs received single-dose daily subcutaneous dalcinonacog alfa injections for six days. Factor IX antigen and activity, whole blood clotting time, and activated partial thromboplastin time were measured at various time points. Additionally, safety assessments for clinical adverse events and evaluations of laboratory test results were conducted.

Results

There was an increase in plasma factor IX antigen with daily subcutaneous dalcinonacog alfa. Bioavailability of subcutaneous dalcinonacog alfa was 10.3% in hemophilia B dogs. Daily subcutaneous dosing of dalcinonacog alfa demonstrated the effects of bioavailability, time to maximal concentration, and half-life by reaching a steady-state activity sufficient to correct severe hemophilia to normal, after four days.

Conclusion

The increased potency of dalcinonacog alfa facilitated the initiation and completion of the Phase 1/2 subcutaneous dosing study in individuals with hemophilia B.

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.

Background and purpose

The advent of intra-arterial neurothrombectomy (IAT) for acute ischemic stroke opens a potentially transformative opportunity to improve neuroprotection studies. Combining a putative neuroprotectant with recanalization could produce more powerful trials but could introduce heterogeneity and adverse event possibilities. We sought to demonstrate feasibility of IAT in neuroprotectant trials by defining IAT selection criteria for an ongoing neuroprotectant clinical trial.

Methods

The study drug, 3K3A-APC, is a pleiotropic cytoprotectant and may reduce thrombolysis-associated hemorrhage. The NeuroNEXT trial NN104 (RHAPSODY) is designed to establish a maximally tolerated dose of 3K3A-APC. Each trial site provided their IAT selection criteria. An expert panel reviewed site criteria and published evidence. Finally, the trial leadership designed IAT selection criteria.

Results

Derived selection criteria reflected consistency among the sites and comparability to published IAT trials. A protocol amendment allowing IAT (and relaxed age, National Institutes of Health Stroke Scale, and time limits) in the RHAPSODY trial was implemented on June 15, 2015. Recruitment before and after the amendment improved from 8 enrolled patients (601 screened, 1.3%) to 51 patients (821 screened, 6.2%; odds ratio [95% confidence limit] of 4.9 [2.3-10.4]; P<0.001). Gross recruitment was 0.11 patients per site month versus 0.43 patients per site per month, respectively, before and after the amendment.

Conclusions

It is feasible to include IAT in a neuroprotectant trial for acute ischemic stroke. Criteria are presented for including such patients in a manner that is consistent with published evidence for IAT while still preserving the ability to test the role of the putative neuroprotectant.

Clinical trial registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02222714.