OREANDA-NEWS. Ablynx today announced that a post-hoc analysis of the worldwide Phase II TITAN study of its wholly-owned Nanobody®, caplacizumab, in patients with acquired thrombotic thrombocytopenic purpura (aTTP), will be presented at the 21st Congress of the European Hematology Association (EHA), being held from 9-12 June 2016 in Copenhagen, Denmark.

It has been previously reported that the efficacy and safety of caplacizumab in conjunction with the standard of care (plasma exchange) were evaluated in a Phase II study in 75 patients with aTTP. Caplacizumab was well-tolerated and the primary endpoint of a reduction in time to platelet normalisation was achieved with statistical significance (p= 0.005). In addition, during treatment, caplacizumab reduced aTTP recurrences by 71% compared to placebo when administered as an adjunct to standard of care[1].

Despite the current standard of care, mortality from an episode of acquired TTP is still reported to be up to 20% and patients remain at risk of life-threatening thrombotic complications. A post-hoc analysis of the Phase II data was performed to assess the impact of caplacizumab on a composite endpoint of major thromboembolic events and TTP-related mortality. The results demonstrate that a significantly lower proportion of subjects treated with caplacizumab experienced one or more major thromboembolic events, or died, as compared to placebo (11.4% versus 43.2%, nominal p-value of 0.006). These clinically meaningful results suggest that treatment with caplacizumab has the potential to reduce the major morbidity and mortality associated with acquired TTP.

The results from this post-hoc analysis will be presented during a poster presentation on 10 June 2016, from 17:15 to 18:45 CET (poster Hall H). 

About caplacizumab and the TITAN study results

Caplacizumab is a highly potent and selective bivalent anti-von Willebrand Factor (vWF) Nanobody that received Orphan Drug Designation in the USA and EU in 2009. Caplacizumab inhibits the interaction between ultra-large vWF and platelets by targeting the A1 domain of vWF. It thereby prevents platelet aggregation and the formation of micro-clots during the acute, critical phase of acquired TTP.

Caplacizumab's clinical effect was demonstrated in the Phase II TITAN study in 75 patients with aTTP:

  • As indicated by a nearly 40% reduction in median time to platelet count normalisation (p = 0.005). Treatment with caplacizumab reduced the use of daily plasma exchange (PEX) and prevented further formation of micro clots and small blood vessel occlusion.
  • As shown by the low number of recurrences requiring re-initiation of daily plasma exchange during treatment with caplacizumab (N=3) vs. placebo (N=11).

These results will serve as the basis for filing for conditional approval of caplacizumab in Europe in H1 2017. The confirmatory Phase III HERCULES study is currently ongoing to support the BLA filing in the USA. Results from this Phase III study are expected by the end of 2017. Caplacizumab could be the first therapeutic specifically approved for the treatment of acquired TTP.

Ablynx is a biopharmaceutical company engaged in the development of Nanobodies®, proprietary therapeutic proteins based on single-domain antibody fragments, which combine the advantages of conventional antibody drugs with some of the features of small-molecule drugs. Ablynx is dedicated to creating new medicines which will make a real difference to society. Today, the Company has more than 40 proprietary and partnered programmes in development in various therapeutic areas including inflammation, haematology, immuno-oncology, oncology and respiratory disease. The Company has collaborations with multiple pharmaceutical companies including AbbVie, Boehringer Ingelheim, Eddingpharm, Genzyme, Merck & Co., Inc., Merck KGaA, Novartis, Novo Nordisk and Taisho Pharmaceuticals. The Company is headquartered in Ghent, Belgium.