Macrogenics gets to market, but what comes next?

Snippets

In the end, perhaps Macrogenics never needed to talk up a supposedly stronger responding subgroup in Sophia, margetuximab’s breast cancer trial. The Her2-targeting drug, now branded Margenza, was granted an all-comers label by the FDA yesterday in late-line metastatic disease. No mention was allowed on the label of data in carriers of the F-allele, a group of patients in which the company claimed Margenza works better than Herceptin. That has not been definitively proven and it is not inconceivable that Macrogenics will give up on this and try to make the most of the label it has won. With the Her2-targeting space very competitive – Daiichi Sankyo and Astrazeneca’s Enhertu and Seagen’s Tukysa have both seen strong launches – and Margenza carrying two black box warnings, this will be no easy task. Sales forecasts show that Margenza is not expected to make big waves, although should Sophia unexpectedly yield an overall survival benefit at the final readout next year, opinions could shift. In any case it is the remainder of Macrogenics’ pipeline that investors are watching. The first readout of the Mahogany trial early next year is the next big event, with a number of other assets following behind.

Margenza and beyond: a selection of Macrogenics' trials
Trial and setting  Regimens tested  Details 
Sophia: Metastatic, refractory Her2+ breast cancer Margenza + chemo vs Herceptin vs chemo  Final overall survival readout due H2'21
Mahogany; 1L Her2+ gastric cancer  Margenza + retifanlimab (anti-PD-1); + tebotelimab (anti-PD-1xLag-3 bispecific); vs Herceptin + chemo First read out due from cohort A (Her2+PD-1) in H1'21, and decision on whether to expand enrollment for registrational purposes. 
Margot: Stage II-III Her2+ breast cancer Margenza + Perjeta + paclitaxel vs Herceptin + Perjeta + paclitaxel Academic trial, started July 2020. 
Refractory, metastatic solid tumours  MGD013 (tebotelimab, anti-PD-1xLag-3 bispecific) +/- Margenza Basket study primarily of MGD013; expansion cohorts added recently in late-line breast and gastric.
Source: clinicaltrials.gov, company statements.   

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