Sanofi SA's $4.8 billion bet on Nanobody developer Ablynx NV gained further validation Wednesday, with the pharma winning an FDA nod for Cablivi (caplacizumab-yhdp) in rare and sometimes fatal blood disorder acquired thrombotic thrombocytopenic purpura (aTTP). U.S. approval comes about six months after the first commercial nanobody – a single-domain antibody that offers the specificity with the advantages of a smaller-sized molecule – gained approval in Europe for the same indication.