Phase II Biologic Effects Trial of Recombinant Interleukin-11 (rhIL-11, Neumega) in Moderate or Mild Hemophilia A or Von Willebrand Disease Unable to Use DDAVP,
Authors: Ragni Margaret V. , Novelli Enrico M. , Murshed Anila , Merricks Elizabeth P. , Kloos Mark T. , Nichols Timothy C. 
Published: October 2019

Abstract
Abstract 3308

Background:
DDAVP is the treatment of choice for individuals with type 1 von Willebrand disease (VWD), although 20% are unresponsive, and of the 80% who do respond, the VWF increase is transient, as endothelial stores are depleted after 3 days. Further, administration requires a 30- minute intravenous infusion in a medical facility. Plasma-derived concentrates may be used in these settings, but are more costly and have potential risk of transmissible infection. We recently demonstrated that recombinant human IL-11 (rhIL-11, Neumega®), a gp-130 signaling cytokine with hematopoietic and anti-inflammatory activity, increases VWF activity up to 2-fold when given daily by subcutaneous injection, with levels persisting each day it is given, and reduces menstrual and postoperative bleeding. The effects of rhIL-11 in individuals with VWD unresponsive or allergic to DDAVP, or hemophilia A, however, have not been evaluated.

Methods:
We conducted a phase II trial to evaluate the safety and biologic effects of rhIL-11 in VWD patients unresponsive or allergic to DDAVP (VWD-Un) or mild hemophilia A (HemA). rhIL-11 was given subcutaneously at 25 μg/kg daily for 4 days in the non-bleeding state, followed on day 4, 30 minutes after rhIL-11, by one dose of DDAVP intravenously, 0.3 μg/kg, if not contraindicated (pt. 2). Fluid restriction was recommended. Fluid status was assessed by height, weight, and exam. Pre- and post-dosing laboratory assays included the VWD profile, VWF multimers by SDS gel electrophoresis, and platelet VWF mRNA by qPCR.

Results:
The results of the first six subjects, including three with VWD (one type IIB and two type 1 VWD), VWF:RCo 0.10–0.20 U/ml, and three with mild hemophilia A, F.VIII 0.08–0.12 U/ml, are presented. All subjects were healthy, with no hypertension or cardiac disease, and all had normal physical exams and normal EKGs. By day 4, among VWD-Un subjects, there was a 1.2-fold increase in VWF:RCo (15±3% vs. 12±0%); a 1.6-fold increase in VWF:Ag (22±8% vs.14±6%); and a 1.3-fold increase in VIII:C (34±36% vs. 27±10%), as compared with pre-rhIL-11 levels (Figure). Following DDAVP (except pt. 2), there was an additional 2.0-fold, 1.7-fold, and 2.6-fold increase in VWF:RCo, VWF:Ag, and VIII:C, respectively. Among HemA subjects, by day 4, there was a 1.8-fold increase in VWF:RCo (160±25% vs. 88±12%); a 1.8-fold increase in VWF:Ag (182±28% vs.99±18%), p<0.01; and a 1.5-fold increase in VIII:C (21±8% vs. 14±5%), as compared with pre-rhIL-11 levels. Following DDAVP, there was an additional 1.5-fold (p<0.01), 1.7-fold, and 2.8-fold (p<0.05) increase in VWF:RCo, VWF:Ag, and VIII:C, respectively. The drug was well tolerated well with less than grade 1 mild conjunctival erythema, local erythema and tenderness at the injection site; in one subject transient hyponatremia, Na 129 meq/L, occurred after excess oral fluid intake for diabetic hyperglycemia, which resolved with fluid restriction.

Discussion:
These data suggest that rhIL-11 increases VWF and VIII levels modestly in VWD patients unresponsive/allergic to DDAVP, and in mild hemophilia A, suggesting the potential use in treatment of clinical bleeding in these disorders.

Disclosures:
No relevant conflicts of interest to declare.