What CEO Daniel Gold called a "ticking time bomb" apparently went off in the 102-patient phase II trial testing MEI Pharma Inc.'s histone deacetylase (HDAC) inhibitor pracinostat in combination with Vidaza (azacitidine, Celgene Corp.) against previously untreated intermediate-2 or high-risk myelodysplastic syndrome (MDS), as top-line data show the pair performed no better than Vidaza by itself.