In the span of three weeks,
cancer drugs Gleevec imatinib and Sprycel dasatinib have shown divergent
signals in pulmonary arterial hypertension. Gleevec met the primary endpoint of
treating PAH symptoms in a Phase III trial, while FDA updated Sprycel's
label to include warnings of increased PAH risk. The likely reason the two
tyrosine kinase inhibitors showed polar opposite activity is that Sprycel hits
a broader range of kinases than Gleevec.
In September, Novartis
AG announced that Gleevec plus standard of care (SOC) met the primary
endpoint of a significant improvement in 6-minute walk distance (6MWD) compared
to placebo plus SOC in the Phase III IMPRES trial in PAH (see BioCentury,
Oct. 10).