You will be shown biomedical passages and your task is to the answer the provided question. Provide a concise and accurate response and do not include any additional text in the response other than the answer.

Question: Which molecule is targeted by Caplacizumab?

Context: Caplacizumab, a nanobody that blocks the interaction between VWF and platelets, has shown promising results in decreasing the time to recover from the acute events that will hopefully translate into long-term clinical benefit for patients.
Ablynx, a Sanofi Company, has developed the anti-von Willebrand factor Nanobody® caplacizumab (Cablivi™) for the treatment of acquired thrombotic thrombocytopenic purpura (aTTP).
Promising agents under evaluation include N-acetylcysteine, bortezomib, recombinant ADAMTS13 and caplacizumab, an inhibitor of the glycoprotein-Ib/IX-von Willebrand factor axis.
The most promising candidates for future treatment of TTP are: rituximab for termination of the autoimmune process, caplacizumab for prevention of platelet-VWF-interaction, and recombinant ADAMTS13 for replacement of the inhibited or missing enzyme.
Promising agents under evaluation include caplacizumab (an inhibitor of the glycoprotein-Ib/IX-Von-Willebrand factor axis), N-acetylcysteine, recombinant ADAMTS13, and anti-plasmocyte compounds.
In the phase II TITAN study, treatment with caplacizumab, an anti-von Willebrand factor Nanobody® was shown to reduce the time to confirmed platelet count normalization and exacerbations during treatment.
It is now anticipated that the first VHH-based antibody drug, Caplacizumab, a bivalent anti-vWF antibody for treating rare blood clotting disorders, may be approved and commercialized in 2018 or shortly thereafter.
Daily plasma exchange and immunosuppressive therapies induce remission, but mortality and morbidity due to microthrombosis remain high.<br><b>METHODS</b>: Caplacizumab, an anti-von Willebrand factor humanized single-variable-domain immunoglobulin (Nanobody), inhibits the interaction between ultralarge von Willebrand factor multimers and platelets.
von Willebrand factor