Let’s add one more big loser to the lengthy roster of wins and defeats during the ASCO preview round.
Syndax Pharmaceuticals shares $SNDX were hit hard after it released abstracts followed by a press release demonstrating that a combination of their HDAC entinostat plus Keytruda produced an objective response rate of only 11% in pre-treated cancer patients — with a progression-free survival rate of only 2.5 months.
Those are lethal numbers for a mid-stage cancer study, and their stock tumbled 23% Thursday. It was particularly disappointing after the biotech reported a year ago that they were tracking a 31% response rate in the study.
Syndax chief Briggs Morrison, an AstraZeneca vet who made the jump to biotech several years ago, has been searching for a way out of the box he’s in. And he believes he’s found that by doing some post hoc analysis that identified a subgroup of patients who did better.
If you whittle the 57 patients reviewed for this readout down to 14 with high monocyte levels, says the company, you’ll get a PFS rate of 5.4 months and an ORR of 29%. And if regulators agree, he wants to follow that clue into a registration study.
It’s not ideal, but it’s all they have.
“Monocyte levels may reflect the ability of the immune system to respond after elimination of immune suppression,” said Dmitry Gabrilovich from The Wistar Institute. “The data from this PD-1 pre-treated population suggest that monocytes are associated with positive clinical outcome from entinostat combined with pembrolizumab, and if confirmed, can potentially be used for patient selection in future studies.”
The early roundup of ASCO data will be followed in a couple of weeks by the main event. We’re tracking several key drugs in the process and will be on site for the big show in Chicago.
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