UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported): March 2, 2020

UNUM THERAPEUTICS INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (617) 945-5576

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

Item 2.05 Costs Associated with Exit or Disposal Activities.

On February 25, 2020, the Board of Directors (the “Board”) of Unum Therapeutics Inc. (the “Company”) approved a reduction in force resulting in the termination of 43 employees, or approximately 60% of the Company’s workforce. These reductions are expected to be substantially completed by the end of the first quarter of 2020. The reduction in force was approved in connection with the Company’s implementation of a new strategic effort which prioritizes and allocates resources towards the advancement of its preclinical program, BOXR1030, for the treatment of advanced solid tumor cancers. As a result of the reduction in force, the Company estimates that it will incur aggregate charges of approximately $2.0 million, in one-time cash expenditures for severance and employee termination related costs.

In addition, as part of the implementation of the new strategic effort, the Company is concluding its clinical trials of ACTR707, including the Phase 1 trial (ATTCK-20-03) in combination with rituximab in patients with relapsed/refractory non-Hodgkin lymphoma and the Phase 1 trial (ATTCK-34-01) in combination with trastuzumab to treat advanced HER2+ solid tumor cancers (the “Clinical Trials”). As a result, the Company expects to incur wind down charges associated with the conclusion of the Clinical Trials that it will report in future quarters.

The estimates of costs that the Company expects to incur and the timing thereof are subject to a number of assumptions and actual results may differ.

Item 8.01 Other Events.

On March 2, 2020, the Company issued a press release titled “Unum Therapeutics Implements Strategic Restructuring to Prioritize Efforts on BOXR1030 for the Treatment of Solid Tumor Cancers” A copy of the press release is filed herewith as Exhibit 99.1 to this Report on Form 8-K and is incorporated herein by reference.     

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 99.1

Unum Therapeutics Implements Strategic Restructuring to Prioritize Efforts on

BOXR1030 for the Treatment of Solid Tumor Cancers

-BOXR1030 is a GPC3-targeted CAR T cell incorporating the novel GOT2 transgene

designed to improve T cell function in the solid tumor microenvironment by enhancing

T cell metabolism-

-Investigational new drug (IND)-enabling studies are underway for BOXR1030 with

plans to submit an application to the FDA in late 2020-

-Unum concludes its Phase 1 ACTR707 programs and reduces workforce to focus

solely on BOXR1030-

CAMBRIDGE, MA, March 2, 2020 – Unum Therapeutics Inc. (NASDAQ: UMRX), a biopharmaceutical company focused on developing curative cell therapies for solid tumors, today announced plans to prioritize resources towards advancing its preclinical program, BOXR1030, for the treatment of solid tumor cancers. Unum’s BOXR1030 expresses a glypican-3 (GPC3) targeted CAR and incorporates the novel transgene glutamic-oxaloacetic transaminase 2 (GOT2) to improve T cell function in the solid tumor microenvironment by enhancing T cell metabolism. Unum has initiated formal preclinical development activities, including preclinical safety testing and GMP process development, to support filing an IND application for BOXR1030 in late 2020.

As part of this effort, and to conserve resources for BOXR1030, Unum is concluding its ACTR707 clinical trials, including the Phase 1 trial (ATTCK-20-03) in combination with rituximab in relapsed/refractory non-Hodgkin lymphoma and the Phase 1 trial (ATTCK-34-01) in combination with trastuzumab to treat advanced HER2+ solid tumor cancers. In addition, the company plans to reduce its current workforce by 43 employees (approximately 60 percent) to focus efforts on the BOXR1030 program. Unum also announced today that its Chief Scientific Officer, Seth Ettenberg, Ph.D., has resigned after five years of service in this role to the company. Unum expects to continue to leverage its BOXR discovery platform, potentially in collaboration with partners, to create and develop new BOXR product candidates to address a broad range of solid tumor cancers.

“Following a detailed review of our operations, opportunities, and cash reserves, we believe the decisions announced today are in the best interests of all Unum stakeholders, including patients, clinicians, employees and shareholders,” said Chuck Wilson, Ph.D., President and Chief Executive Officer of Unum Therapeutics. “We remain committed to addressing the challenges of treating solid tumor cancers, and would like to thank the patients, their families, and the investigators who have made our efforts to date possible. In addition, we would like to thank Seth for his contributions to the preclinical discovery efforts here at Unum over the years and wish him the very best in his next endeavor.”

Unum will provide severance, continuation of employee benefits and outplacement assistance to employees affected by the restructuring. As of September 30, 2019, Unum had cash and cash equivalents of $45.9 million. After implementation of this restructuring, Unum’s expects its current cash and cash equivalents to fund the company into mid-2021. Further details on the financial implications of the restructuring will be included in the company’s full-year 2019 results expected later this month and with related filings with the Securities and Exchange Commission.

About Unum’s BOXR1030 and BOXR Platform

Unum’s BOXR1030 was discovered from its Bolt-on Chimeric (BOXR) platform that is designed to discover novel “bolt-on” transgenes to be co-expressed with CARs, a T-cell receptor, or ACTR, to help T cells survive longer and perform better in the solid tumor microenvironment. BOXR candidates consist of two main components: 1) a targeting receptor that directs the T cell to attack tumor cells, which may be a traditional CAR receptor, a T-cell receptor, or Unum’s ACTR receptor, and 2) a novel “bolt-on” transgene that improves the intrinsic function of the T cell. Once discovered, BOXR transgenes are designed to be incorporated into several different types of therapeutic T cells, including both ACTR T cells and CAR-T cells, to impart new functionality to T cells.

Unum’s first product candidate selected from the BOXR platform, BOXR1030, expresses GPC3+ targeted CAR and incorporates the bolt-on GOT2 transgene to improve T cell function in the solid tumor microenvironment (TME) by enhancing T cell metabolism. Preclinical data with BOXR1030 was presented at the Society for Immunotherapy of Cancer (SITC) Annual Meeting in November 2019. In preclinical studies, BOXR1030 T cells were resistant to suppressive TME-like conditions, showing improved T cell proliferation under both hypoxic and low glucose conditions compared with control GPC3+ CAR-T cells. In vivo, BOXR1030 demonstrated superior activity compared to the parental CAR-T with treated animals achieving complete tumor regressions. Tumor infiltrating lymphocytes isolated from the tumors of treated animals revealed that BOXR1030 cells were more resistant to dysfunction and had fewer markers of exhaustion as compared to the control CAR-T cells.

About Unum Therapeutics

Unum Therapeutics is a biopharmaceutical company focused on developing curative cell therapies to treat patients with solid tumor cancers. Unum’s novel proprietary technology includes BOXR, which is designed to improve the functionality of engineered T cells by incorporating a “bolt-on” transgene to overcome resistance of the solid tumor microenvironment to T cell attack. Unum’s preclinical program BOXR1030 expresses the GOT2 transgene and targets GPC3+ solid tumor cancers. The Company is headquartered in Cambridge, MA.

Follow Unum Therapeutics on social media: @UnumRx, and LinkedIn.

Forward looking Statements

This press release contains forward-looking statements including, without limitation, statements regarding our future expectations, plans and prospects, including projections regarding our long-term growth, enrollment and results for our preclinical and clinical activities, the development of our product candidate, BOXR1030, and the anticipated timing and success of any of our preclinical studies, clinical trials and regulatory filings, and our strategies, business plans, and focus, as well as other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “will,” or “would” and similar expressions, constitute forward-looking statements within the meaning of the safe harbor provisions of The Private Securities Litigation Reform Act of 1995, as amended. We may not actually achieve the forecasts disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results could differ materially from the projections disclosed in the forward-looking statements we make as a result of a variety of risks and uncertainties, including risks related to the accuracy of our estimates regarding expenses, future revenues, capital requirements, and the need for additional financing, the success, cost and timing of our product development activities and clinical trials, our ability to obtain and maintain regulatory approval for our product candidates, and the other risks and uncertainties described in the “Risk Factors” sections of our public filings with the Securities and Exchange Commission. In addition, the forward-looking statements included in this press release represent our views as of the date hereof. We anticipate that subsequent events and developments may cause our views to change. However, while we may elect to update these forward-looking statements at some point in the future, we specifically disclaim any obligation to do so. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date hereof.

Investor Contact:

Stern Investor Relations, Inc.

Stephanie Ascher, 212-362-1200

stephanie@sternir.com

Media Contact:

Lissette Steele, 202-930-4762

lsteele@vergescientific.com