Unum IPO hits bottom of range, netting $62M for cell therapy cancer trials

Unum Therapeutics has netted $62 million in a Nasdaq IPO. The total falls short of the amount Unum set out to raise but leaves the biotech with enough cash to advance two cell therapy candidates in four clinical trials.

Cambridge, Mass.-based Unum had hoped to sell its shares for as much as $14 apiece but ultimately settled for $12, the bottom end of the range. That could be seen as an underwhelming result for a biotech in the red-hot oncology cell therapy field, but it means Unum has come through a wobble caused by patient deaths and raised enough money to execute the next stage of its R&D strategy.

Unum plans to spend about $20 million to finish a phase 1 trial of its lead antibody-coupled T cell receptor, ACTR087, in combination with rituximab in adults with relapsed or refractory B cell non-Hodgkin lymphoma (NHL). That is the trial in which two patients died from drug-related adverse events and a third died after suffering a severe case of cytokine release syndrome linked to ACTR087.

The FDA put the trial on a clinical hold at one point but lifted the restrictions shortly before Unum filed to go public. Unum rolled out safety management and monitoring guidelines to improve the detection and treatment of adverse events but acknowledges the trial could hit further safety issues. Such events happen in early-phase cancer trials but are a headwind for a biotech that frames its technology as a way to “maximize tumor-killing activity and minimize toxicity.”

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Unum will use another tranche of the IPO haul to fund a phase 2 trial of ACTR087 in NHL patients previously treated with CD19 CAR-T therapies—such as Gilead’s Yescarta and Novartis’ Kymriah—into next year .

The rest of the IPO money is earmarked for Unum’s second clinical-phase candidate, ACTR707. As with ACTR087, Unum is looking at ACTR707 in combination with rituximab in adults with relapsed or refractory B cell NHL. A phase 1 trial combining ACTR707 with Herceptin is also on the R&D road map. 

Unum expects its freshly inflated cash pile to see it through to the completion of both rituximab NHL combination trials. At that point, the data will paint a clearer picture of whether Unum has dealt with the safety problems, potentially positioning it to raise a follow-on financing that supports its longer-term plans.