Syndax gets an early menin nod

The good news for Syndax is that it has received FDA approval for the first menin inhibitor, revumenib, in KMT2A-rearranged acute leukaemia, well ahead of its delayed 26 December PDUFA date. The bad news is that the drug's label includes warnings for differentiation syndrome and the heart rhythm side effect QTc prolongation. While the former is likely to be a class effect, the latter hasn’t been seen with Kura’s rival menin inhibitor ziftomenib – which is admittedly behind, and isn’t even being developed as monotherapy in KMT2Ar disease. Syndax has contended that QTc prolongation is easily resolved, and won’t concern doctors, given the seriousness of relapsed/refractory leukaemia. Syndax will launch revumenib, branded Revuforj, this month, at a list price of $39,500 per month, it said during a conference call on Friday. Syndax reckons the KMT2Ar market, totalling around 2,000 US patients, is worth $750m per year. This bigger use will be NPM1-mutant relapsed leukaemia, which affects 3,000-4,500 US patients, and where Syndax recently reported ostensibly positive data that nevertheless sent the group’s stock down 26%. First-line combination efforts are also ongoing. The realities of a solo launch, and the prospect of a potentially less toxic competitor, could be troubling investors.