Syndax Plots $69M IPO For Cancer Drug’s Stretch Run

Xconomy Boston — 

Syndax Pharmaceuticals raised about $27 million in private financing last year to gear up for a late-stage clinical trial. Now, on the doorstep of that lengthy, 600-patient study, the Waltham, MA-based company is looking to Wall Street to get it to the finish line.

Syndax late Thursday revealed plans to raise up to $69 million through an IPO. It’ll use that cash largely to kick off a big Phase 3 trial for experimental cancer drug entinostat, which it’s aiming to position as an adjunct to hormone therapy for patients with breast cancer. Syndax would trade on the Nasdaq under the ticker symbol “SNDX.”

Domain Associates holds 34.3 percent of Syndax’s stock. MPM Capital owns 29.5 percent, followed by RusNanoMedinvest (13.2 percent), Forward Ventures (8.2 percent), and Eddingpharm (5.7 percent). The company has raised more than $80 million in equity financing since its inception in 2005.

Deutsche Bank Securities, Jefferies LLC, JMP Securities, and Wedbush Securities are underwriting the offering.

Syndax was co-founded by Domain Associates and scientists at the Salk Institute for Biological Studies, and licensed entinostat, its lead drug, from Bayer. The molecule is designed to selectively hit histone deacetylases, or HDACs, that are most relevant to tumors. HDACs are a well-known molecular target—Merck’s lymphoma drug vorinostat (Zolinza) and Celgene’s romidepsin (Istodax), for instance, are both HDAC inhibitors.

Syndax’s plan is to position entinostat as an add-on to hormone therapies like aromatase inhibitors for patients with certain types of breast cancer. Basically, entinostat is supposed to make tumor cells more vulnerable to hormone therapy, so that patients can stay on such treatment longer and avoid shifting to chemotherapy and dealing with its more significant side effects. The company has received a breakthrough therapy designation from the FDA, meaning the agency will work more closely to speed up development of the therapy than it otherwise would.

The IPO cash should help Syndax get entinostat through a big late-stage clinical trial of about 600 patients with hormone receptor positive breast cancer. Syndax will run the study with some funding help from the National Cancer Institute, and expects to get the trial underway in April. In the study, men and women with certain forms of breast cancer will get either entinostat in tandem with exemestane, a hormone therapy, or hormone therapy and a placebo.

Syndax has got a long road ahead, however: it expects to take about 40 months to enroll patients in the trial and won’t report data until mid-2017. It’s also trying to make a dent in an ultra-competitive breast cancer field where a couple powerhouses, Pfizer and Novartis, both have late-stage drug candidates (palbociclib and buparlisib, respectively) that target the same patient group Syndax is going after.

Syndax, meanwhile, also wants to use the IPO dollars to run a different mid-stage trial to help identify a biomarker for entinostat’s activity, and plans test the drug out in a third study with an additional, unspecified hormone therapy. Still other trials are already taking place testing the drug in metastatic lung cancer and other tumors, though entinostat has failed a lung cancer trial in the past.