Indirect treatment comparisons of avapritinib versus midostaurin for patients with advanced systemic mastocytosis.

Systemic mastocytosis is a rare blood disorder caused by the build-up of too many abnormal mast cells, a type of white blood cell, in the skin and organs. Patients with advanced systemic mastocytosis have a low life expectancy and limited treatment options. This research aimed to compare the effectiveness of two recent and innovative treatments (called avapritinib and midostaurin) in extending life expectancy and decreasing mast cells and organ damage. As avapritinib and midostaurin were not investigated in the same clinical studies, it was necessary to compare the two treatments using the results from studies of each individual treatment. The published evidence used to support this comparison was systematically searched for and consisted of four clinical studies: the EXPLORER and PATHFINDER studies (investigating avapritinib) and D2201 and A2213 studies (investigating midostaurin). An indirect comparison between the studies was made that adjusted for differences in key patient characteristics. The results suggest that compared with midostaurin, avapritinib has the potential to extend life expectancy and decrease disease burden.