KRAS and myelofibrosis: Although this drug shows preclinical promise and well tolerability, phase II studies of simtuzumab have demonstrated that it has no clinical benefit in patients with idiopathic pulmonary fibrosis, primary myelofibrosis, post-polycythemia vera myelofibrosis, post-essential thrombocythemia myelofibrosis, advanced fibrosis caused by non-alcoholic steatohepatitis, metastatic pancreatic adenocarcinoma and metastatic KRAS mutant colorectal carcinoma [146–149].