Servier leaves Macrogenics again

Were it not for the lingering doubts about Macrogenics’ lead asset, margetuximab, Servier’s ending of a licensing deal for flotetuzumab yesterday would be a non-event. As it is, however, investors have another reason to fret over a share price that, since enthusiasm over margetuximab peaked in February, has slumped 40%. Flotetuzumab is an anti-CD123 bispecific, a mechanism that has proved extremely tricky to exploit without toxicities, as numerous companies have found (Xencor’s bispecific hold reignites debates over approach and target, February 21, 2019). Servier is not a major oncology player, so its decision might not mean much beyond the loss of $308m of possible milestone payments; $35m had already been received in up-front and option fees. Four years ago Servier pulled out of a separate deal covering Macrogenics’ anti-B7-H3 MAb enoblituzumab. Meanwhile, margetuximab, an anti-Her2 MAb, remains mired in concerns revealed at this year’s Asco that its highly touted Sophia trial is unlikely to show an overall survival benefit. The next evidence for or against flotetuzumab will emerge at December’s Ash conference, where a monotherapy trial in acute myelogenous leukaemia and myelodysplastic syndromes should yield updated results.