Form 8-K

8-K — Sensei Biotherapeutics, Inc.

Accession: 0001193125-26-225323

Filed: 2026-05-15

Period: 2026-05-15

CIK: 0001829802

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Results of Operations and Financial Condition

Item: Financial Statements and Exhibits

Documents

8-K — d125741d8k.htm (Primary)

EX-99.1 (d125741dex991.htm)

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8-K

8-K (Primary)

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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): May 15, 2026

Sensei Biotherapeutics, Inc.

(Exact Name of Registrant as Specified in its Charter)

Delaware

001-39980

83-1863385

(State or Other Jurisdiction

of Incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

1405 Research Blvd, Suite 125

Rockville, MD

20850

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s telephone number, including area code: (240) 243-8000

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:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934:

Title of each class

Trading

symbol

Name of each exchange

on which registered

Common Stock

SNSE

The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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 2.02

Results of Operations and Financial Condition.

On May 15, 2026, Sensei Biotherapeutics, Inc. issued a press release announcing its financial results for the quarter ended March 31, 2026. A copy of the press release is attached hereto as Exhibit 99.1.

The information in this Item 2.02 and the exhibit attached hereto are being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall they be deemed incorporated by reference into any filing under the Exchange Act or the Securities Act of 1933, as amended, whether filed before or after the date hereof and regardless of any general incorporation language in such filing.

Item 9.01

Financial Statements and Exhibits.

(d) Exhibits

Exhibit

Number

Exhibit Description

99.1

Press Release of Sensei Biotherapeutics, Inc., dated May 15, 2026

104

The cover page from this Current Report on Form 8-K, formatted in Inline XBRL

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.

Sensei Biotherapeutics, Inc.

Date: May 15, 2026

/s/ Christopher W. Gerry

Christopher W. Gerry

General Counsel and Secretary

EX-99.1

Filename: d125741dex991.htm · Sequence: 2

EX-99.1

Exhibit 99.1

Sensei Biotherapeutics Reports First Quarter 2026 Financial Results and Provides Corporate Update

First patient dosed in Phase 1b/2 trial of PIKTOR in HR+/HER2- advanced breast cancer

Topline Phase 2 data in patients with advanced endometrial cancer expected in second half 2026

BOSTON, Mass., May 15, 2026 – Sensei Biotherapeutics, Inc. (Nasdaq: SNSE) today reported financial results for the first quarter ended

March 31, 2026, and provided a corporate update.

“The first quarter of 2026 was transformational for the Company, with the acquisition of

Faeth Therapeutics and the concurrent $200 million private placement in February, supported by a group of leading life sciences investors,” said Christopher Gerry, President & General Counsel of Sensei Biotherapeutics.

“This acquisition and injection of new capital will allow us to advance PIKTOR, a differentiated multi-node pathway inhibitor, through key clinical milestones.”

“New data across the industry continues to support the significant potential of multi-node inhibition of the PI3K/AKT/mTOR pathway,” said Anand

Parikh, Chief Operating Officer of Sensei Biotherapeutics. “We believe PIKTOR is differentiated as an orally administered multi-node therapy specifically targeting PI3K-alpha, mTORC1 and mTORC2, with the potential to treat a variety of solid

tumors. With our Phase 2 trial in advanced endometrial cancer expected to read out by the end of the year and the recent initiation of our Phase 1b/2 trial in advanced breast cancer, we are making great strides towards delivering the next generation

of solid tumor therapies.”

Clinical Program Highlights

Acquired through the Faeth transaction, PIKTOR is now Sensei’s lead program. The investigational, proprietary,

all-oral combination of serabelisib and sapanisertib is designed to inhibit multiple nodes of the PI3K/AKT/mTOR pathway through PI3K-alpha and dual mTORC1/2 targeting.

•

In April 2026, the first patient was dosed in the Phase 1b/2 trial evaluating PIKTOR for the treatment of

HR+/HER2- advanced breast cancer (Study FTH-PIK-101). Interim data from the trial is expected in 2027.

•

The Phase 2 trial evaluating PIKTOR in advanced endometrial cancer (Study FTH-PIK-201) is on track to report topline data in the second half of 2026.

First Quarter

2026 Financial Results

Cash Position: Cash, cash equivalents and marketable securities were $202.8 million as of March 31, 2026, as

compared to $21.2 million as of December 31, 2025.

Research and Development (R&D) Expenses: R&D expenses were $18.0 million

for the quarter ended March 31, 2026, compared with $3.7 million for the quarter ended March 31, 2025. The increase in R&D expenses was primarily attributable to the inclusion of Faeth R&D operations as well as one-time costs associated with the Faeth acquisition, partially offset by a reduction in the SNS-101 clinical trial costs.

General and Administrative (G&A) Expenses: G&A expenses were $19.7 million for the

quarter ended March 31, 2026, compared to $3.5 million for the quarter ended March 31, 2025. The increase in G&A expense was primarily attributable to one-time costs associated with the

Faeth acquisition.

Acquired In-Process Research and Development (Acquired IPR&D) Expenses: Acquired

IPR&D expenses were $133.0 million for the quarter ended March 31, 2026. This represents the fair value of IPR&D assets obtained in connection with asset acquisition where the acquired IPR&D has no alternative future use as of

the acquisition date.

Net Loss: Net loss was $170.2 million, or $131.45 per basic and diluted share, for the quarter ended March 31,

2026, compared with a net loss of $6.9 million, or $5.45 per basic and diluted share, for the quarter ended March 31, 2025.

Weighted-average

common shares outstanding, basic and diluted, were 1,295,052 for the quarter ended March 31, 2026, compared with 1,259,531 for the quarter ended March 31, 2025.

Condensed Statements of Operations

(Unaudited, in thousands except share and per share data)

For the Three Months

Ended March 31,

2026

2025

Operating expenses:

Research and development

17,957

3,725

General and administrative

19,713

3,549

Acquired in-process research and development

132,957

—

Total operating expenses

170,627

7,274

Loss from operations

(170,627

)

(7,274

)

Total other income

391

410

Net loss

(170,236

)

(6,864

)

Net loss per share, basic and diluted

(131.45

)

(5.45

)

Weighted-average common shares outstanding, basic and diluted

1,295,052

1,259,531

Selected Condensed Balance Sheet Data

(Unaudited, in thousands)

March 31,

2026

December 31,

2025

Cash and cash equivalents

152,325

8,668

Marketable securities

50,468

12,516

Total assets

205,381

22,902

Total liabilities

14,191

4,310

Series B redeemable convertible preferred stock.

328,476

—

Total stockholders’ (deficit) equity

(137,286

)

18,592

About Sensei Biotherapeutics

Sensei Biotherapeutics, Inc. (Nasdaq: SNSE) is a clinical-stage biotechnology company focused on improving outcomes for cancer patients through multi-node

inhibition of critical oncogenic pathways. Following the acquisition of Faeth Therapeutics, Sensei’s lead program is PIKTOR, an investigational multi-node inhibitor of the PI3K/AKT/mTOR pathway in development for endometrial and breast cancer.

Sensei is also completing a Phase 1/2 trial of solnerstotug, its V-domain Ig suppressor of T cell activation (VISTA) inhibitor, in patients with advanced solid tumors. Sensei intends to use its website as a

means of disclosing material non-public information and for complying with its disclosure obligations under Regulation FD. For more information, please visit www.senseibio.com and follow the company on

X @SenseiBio and LinkedIn.

Cautionary Note Regarding Forward-Looking Statements

Certain statements in this press release, other than purely historical information, may constitute “forward-looking statements” within the meaning

of the federal securities laws, including for purposes of the safe harbor provisions under the United States Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied

statements relating to the company’s expectations, hopes, beliefs, intentions or strategies regarding the future including, without limitation, statements regarding: the expected benefits or opportunities following the acquisition of Faeth

Therapeutics; expectations regarding or plans for the company’s pipeline, including the Phase 2 trial evaluating PIKTOR in advanced endometrial cancer and the expected timing for topline data, the Phase 1b/2 trial evaluating PIKTOR in

HR+/HER2- advanced breast cancer and the expected timing for interim data, the completion of the remaining portion of the Phase 1/2 trial of solnerstotug and other research and development programs and the expected timing for key milestones; the

potential benefits of PIKTOR, including its potential to treat a variety of solid tumors; expectations regarding the use of proceeds from the private placement and cash runway expectations therefrom, including such proceeds funding the company

through key clinical milestones. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words

“opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “aim,” “strategy,” “target,” “seek,”

“anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,”

“might,” “plan,” “possible,” “predict,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or

variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future

developments and their potential effects. There can be no assurance that future developments affecting the company will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are

beyond the company’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not

limited to those uncertainties and factors described under the heading “Risk Factors” and “Summary of Risk Factors” in the company’s Quarterly Report on Form 10-Q, filed with the

Securities and Exchange Commission (the “SEC”) on May 14, 2026, as well as discussions of potential risks, uncertainties, and other important factors included in other filings by the company from time to time, as well as risk

factors associated with companies, such as Faeth, that operate in the biotechnology industry. Should one or more of these risks or uncertainties materialize, or should any of the company’s assumptions prove incorrect, actual results may vary

in material respects from those projected in these forward-looking statements. Nothing in this press release should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of

the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this press release, which speak only as of the date they are made and are qualified in their entirety

by reference to the cautionary statements herein. The company does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This press release does not purport to summarize all of the

conditions, risks and other attributes of an investment in the company.

Investor Contact:

Stephanie Ascher, Precision AQ

Stephanie.ascher@precisionaq.com

Media Contact:

Patrick Schmidt, Consort Partners

senseibio@consortpartners.com

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