Commitments and Contingencies	6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies License and Other Agreements Sesame Therapeutics, Inc. In August 2023, the Company received an inconsequential equity stake in Sesame, a related party, in exchange for providing lab space and resources for the early phases of company development. The Company concluded that the common stock investment should be accounted for as an equity investment. Sesame's common stock is not exchange-traded and does not have a readily determinable fair value. Therefore, the Company accounts for the common stock investment under the measurement alternative for equity investments that do not have a readily determinable fair value. During 2025, an observable price change event occurred, resulting in the $0.5 million increase in fair value recognized related to the common stock investment as a result of the application of the measurement alternative. As of December 31, 2025, the cost of the investment in Sesame’s common stock was $0.5 million, including immaterial transaction costs, and was recorded as an equity investment within Other current assets on the consolidated balance sheets. There were no observable price changes that would result in an adjustment to the fair value of this equity investment during the three and six months ended June 30, 2026. In June 2024, the Company and Sesame entered into the Sesame Agreement. Pursuant to the Sesame Agreement, the Company received a $0.1 million upfront, non-refundable payment in June 2024. Under the terms of the Sesame Agreement, the Company is eligible to receive up to $25.9 million in potential future clinical, regulatory, and commercial milestone event payments. The Company is also eligible to receive low single-digit tiered royalties on net sales of any product covered by a licensed patent. The Company evaluated the Sesame Agreement under ASC 606. The Company identified the following promises under the agreement: (1) the non-exclusive license and (2) the initial know-how transfer, and determined that the promises were immaterial as the upfront license payment at contract inception was an inconsequential payment amount. The initial upfront license payment was recorded as license revenue on the consolidated statements of operations and comprehensive loss during the period ended June 30, 2024. All potential future milestone payments are considered to be variable consideration and have been excluded from the transaction price. Revenue for all potential clinical and regulatory milestone achievements will be recognized when the related milestones are achieved or when it becomes probable that a significant reversal in the amount of revenue recognized relating to the milestone event will not occur. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. Additionally, revenue related to potential sales milestones and royalties from the sales of the licensed products will be recognized when the related sales occur. In August 2025, the Company and Sesame entered into a use and occupancy sub-lease of office and laboratory space at 201 Brookline Avenue in Boston, Massachusetts. The sub-lease has a term of 17-months with an option to extend for one additional six-month period. Total sub-lease payments from Sesame to the Company will approximate $0.4 million over the term of the sub-lease agreement. Due to common relationships amongst current and former members of management and the boards of directors, the transaction above with Sesame is a related party transaction. Clinical Trial Collaboration and Supply Agreements In November 2024, the Company and Revolution Medicines entered into a CTCSA. The CTCSA with Revolution Medicines provides that Revolution Medicines will supply daraxonrasib (RMC-6236), a RAS(ON) multi-selective inhibitor, and zoldonrasib (RMC-9805), a RAS(ON) G12D-selective inhibitor, at no cost to the Company for use in trials that will include vopimetostat and each of these RAS(ON) inhibitors. The Company will be the sponsor of any combination trials and bear associated costs. Each company will retain commercial rights to its respective compounds, and the agreement is mutually non-exclusive. Due to common relationships amongst members of management and the boards of directors, this transaction is a related party transaction. Given the differentiated profile of vopimetostat enabling the potential for efficacious and tolerable RAS inhibitor combinations, in March 2026, the Company entered into a CTCSA with Erasca to evaluate vopimetostat in combination with Erasca’s pan-RAS molecular glue, ERAS-0015. Under the terms of the agreement, Tango is the sponsor of the trial and Erasca is supplying ERAS-0015 at no cost. Each company will retain commercial rights to its respective compound, and the agreement is mutually non-exclusive. Other Funding Commitments As of June 30, 2026, the Company had ongoing preclinical and clinical studies. The Company enters into contracts in the normal course of business with contract research organizations in connection with the preparation and operation of clinical trials, professional consultants for expert advice and other vendors for clinical supply manufacturing or other preclinical and clinical services. These contracts are generally cancellable, with notice, at the Company's option and do not have significant cancellation penalties. Guarantees The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with directors and officers, business partners, contractors, landlords, construction companies, contract research organizations, clinical trial sites, and other parties. Under these provisions, the Company generally indemnifies, defends and holds harmless the indemnified party for losses suffered or incurred by the indemnified party under the terms of the contract, including as a result of the Company’s activities. These indemnification provisions generally survive termination of the underlying agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date, the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal. Litigation The Company, from time to time, may be party to litigation arising in the ordinary course of business. The Company was not subject to any material legal proceedings as of June 30, 2026, and no material legal proceedings are currently pending or threatened. Because of uncertainties related to claims, proceedings and litigation, assessments of potential liabilities are based on the Company's best estimates based on information available at the time of the assessment. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation, court decisions or settlement of claims (and offers of settlement), the Company may reassess the potential liability related to these matters and may revise these estimates, which could result in a material adverse effect on the operating results of the Company. Costs associated with involvement in legal proceedings are expensed as incurred. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. If the Company were to be unable to prevail in any such proceedings, the consolidated financial position, results of operations, and future cash flows of the Company may be materially impacted.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2026

Commitments and Contingencies Disclosure [Abstract]

License and Other Agreements

Sesame Therapeutics, Inc.

In August 2023, the Company received an inconsequential equity stake in Sesame, a related party, in exchange for providing lab space and resources for the early phases of company development. The Company concluded that the common stock investment should be accounted for as an equity investment. Sesame's common stock is not exchange-traded and does not have a readily determinable fair value. Therefore, the Company accounts for the common stock investment under the measurement alternative for equity investments that do not have a readily determinable fair value. During 2025, an observable price change event occurred, resulting in the $0.5 million increase in fair value recognized related to the common stock investment as a result of the application of the measurement alternative. As of December 31, 2025, the cost of the investment in Sesame’s common stock was $0.5 million, including immaterial transaction costs, and was recorded as an equity investment within Other current assets on the consolidated balance sheets. There were no observable price changes that would result in an adjustment to the fair value of this equity investment during the three and six months ended June 30, 2026.

In June 2024, the Company and Sesame entered into the Sesame Agreement. Pursuant to the Sesame Agreement, the Company received a $0.1 million upfront, non-refundable payment in June 2024. Under the terms of the Sesame Agreement, the Company is eligible to receive up to $25.9 million in potential future clinical, regulatory, and commercial milestone event payments. The Company is also eligible to receive low single-digit tiered royalties on net sales of any product covered by a licensed patent.

The Company evaluated the Sesame Agreement under ASC 606. The Company identified the following promises under the agreement: (1) the non-exclusive license and (2) the initial know-how transfer, and determined that the promises were immaterial as the upfront license payment at contract inception was an inconsequential payment amount. The initial upfront license payment

was recorded as license revenue on the consolidated statements of operations and comprehensive loss during the period ended June 30, 2024.

All potential future milestone payments are considered to be variable consideration and have been excluded from the transaction price. Revenue for all potential clinical and regulatory milestone achievements will be recognized when the related milestones are achieved or when it becomes probable that a significant reversal in the amount of revenue recognized relating to the milestone event will not occur. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. Additionally, revenue related to potential sales milestones and royalties from the sales of the licensed products will be recognized when the related sales occur.

In August 2025, the Company and Sesame entered into a use and occupancy sub-lease of office and laboratory space at 201 Brookline Avenue in Boston, Massachusetts. The sub-lease has a term of 17-months with an option to extend for one additional six-month period. Total sub-lease payments from Sesame to the Company will approximate $0.4 million over the term of the sub-lease agreement.

Due to common relationships amongst current and former members of management and the boards of directors, the transaction above with Sesame is a related party transaction.

Clinical Trial Collaboration and Supply Agreements

In November 2024, the Company and Revolution Medicines entered into a CTCSA. The CTCSA with Revolution Medicines provides that Revolution Medicines will supply daraxonrasib (RMC-6236), a RAS(ON) multi-selective inhibitor, and zoldonrasib (RMC-9805), a RAS(ON) G12D-selective inhibitor, at no cost to the Company for use in trials that will include vopimetostat and each of these RAS(ON) inhibitors. The Company will be the sponsor of any combination trials and bear associated costs. Each company will retain commercial rights to its respective compounds, and the agreement is mutually non-exclusive. Due to common relationships amongst members of management and the boards of directors, this transaction is a related party transaction.

Given the differentiated profile of vopimetostat enabling the potential for efficacious and tolerable RAS inhibitor combinations, in March 2026, the Company entered into a CTCSA with Erasca to evaluate vopimetostat in combination with Erasca’s pan-RAS molecular glue, ERAS-0015. Under the terms of the agreement, Tango is the sponsor of the trial and Erasca is supplying ERAS-0015 at no cost. Each company will retain commercial rights to its respective compound, and the agreement is mutually non-exclusive.

Other Funding Commitments

As of June 30, 2026, the Company had ongoing preclinical and clinical studies. The Company enters into contracts in the normal course of business with contract research organizations in connection with the preparation and operation of clinical trials, professional consultants for expert advice and other vendors for clinical supply manufacturing or other preclinical and clinical services. These contracts are generally cancellable, with notice, at the Company's option and do not have significant cancellation penalties.

Guarantees

The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with directors and officers, business partners, contractors, landlords, construction companies, contract research organizations, clinical trial sites, and other parties. Under these provisions, the Company generally indemnifies, defends and holds harmless the indemnified party for losses suffered or incurred by the indemnified party under the terms of the contract, including as a result of the Company’s activities. These indemnification provisions generally survive termination of the underlying agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date, the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal.

Litigation

The Company, from time to time, may be party to litigation arising in the ordinary course of business. The Company was not subject to any material legal proceedings as of June 30, 2026, and no material legal proceedings are currently pending or threatened. Because of uncertainties related to claims, proceedings and litigation, assessments of potential liabilities are based on

the Company's best estimates based on information available at the time of the assessment. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation, court decisions or settlement of claims (and offers of settlement), the Company may reassess the potential liability related to these matters and may revise these estimates, which could result in a material adverse effect on the operating results of the Company. Costs associated with involvement in legal proceedings are expensed as incurred. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. If the Company were to be unable to prevail in any such proceedings, the consolidated financial position, results of operations, and future cash flows of the Company may be materially impacted.