Failure-prone Unum cuts jobs, loses scientific chief, and changes focus yet again
Atlas Venture-backed Unum, which once harbored ambitions to rival the two CAR-T therapies Kymriah and Yescarta, is paying the price for a laundry list of setbacks.

On Monday, the Cambridge, Massachusetts-based company said it was cutting its workforce by 43 employees (roughly 60% of the total headcount) to focus its efforts on a preclinical program. It also disclosed the departure of its chief scientific officer, Seth Ettenberg, as it ceases the development of trials harnessing its maiden technology: ACTR.
The trials shelved include an early-stage lymphoma program testing the experimental drug, ACTR707, in combination with rituximab (Roche’s MabThera), as well as a Phase I solid tumor trial evaluating the combination of ACTR707 and trastuzumab (Roche’s Herceptin).
Cell therapies under the platform were engineered to arm a patient’s T cells with the arsenal to launch a double attack on cancer cells. First, the cells are designed to express ACTR — a chimeric protein made out of components from T cells and natural killer cells — and then are combined with the tumor-targeting ability of co-administered antibodies.
The platform has seen failure after failure. Back in 2018, in its IPO filing, the company disclosed that two out of nine patients in the high-dose arm of a clinical trial for their then-lead cell therapy — ACTR087 — had died, forcing the FDA to impose a clinical hold that was lifted just ahead of their bid to go public. While it broke no laws, the company’s approach to transparency didn’t win it any plaudits — the IPO was priced at the bottom of the range.
Then, last year, things got worse. Executives in July revealed that the FDA had slapped another clinical hold on ACTR087, after a patient in the safety cohort of a Phase I study experienced a raft of serious adverse events. By this time, Unum — which is also backed by F-Prime Capital — had reprioritized its pipeline to focus on ACTR707.
Come November, ACTR087 was formally abandoned amid a broader shift from hematology to solid tumors. The company’s other tech platform, BOXR, hit the spotlight.
The tumor microenvironment in many solid tumor cancers is deeply immunosuppressive, blocking T cells from functioning normally. Unum’s Bolt-on Chimeric Receptor (BOXR) is designed to “bolt-on” transgenes to boost intrinsic T cell functionality to conquer that immunosuppression.
In Unum’s latest update, it looks like ACTR707 has also made the scrap heap — leaving preclinical BOXR1030 as the sole focus. The company’s shares $UMRX waded deeper into penny stock territory, dipping slightly premarket to 54 cents.
Regenerative stem cell player BlueRock Therapeutics, meanwhile, has scored the services of Unum’s erstwhile CSO Ettenberg.