The study was in myelofibrosis – a severe disorder of blood formation for which is extremely difficult to treat. Myelofibrosis is triggered by bone marrow scarring which causes blood formation to switch to other organs such as the liver and spleen. Faced with this extra burden these organs swell enormously. Anemia is a common consequence too.
YM BioSciences’ Janus associated kinase (JAK)-1/2 inhibitor drug CYT387 was able to induce a 50% reduction in spleen size and improvements in anemia in an interim analysis of Phase I/II data.
JAK-inhibitors are an emerging class of drugs which act on a fundamental step in the myelofibrosis disease process. Currently there are several companies vying to develop and launch JAK-inhibitors in myelofibrosis:
Incyte – INCB18424 (JAK-2 inhibitor) – Phase III
S*BIO – SB1518 (JAK-2/FLT-3 inhibitor) – Phase I/II (complete)
YM BioSciences – CYT387 (JAK-1/2 inhibitor) – Phase I/II
sanofi aventis – TG101348 ((JAK-2/FLT-3 inhibitor) – Phase I/II
AstraZeneca – AZD1480 ((JAK-2 inhibitor) – Phase I
Much more clinical development remains, but if the dual activity of YM’s drug against JAK 1 and JAK 2 turns out to be key for minimizing effects on the spleen and reversing anemia then YM could turn out to have a winner.