Nature of the Business	3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Sage Therapeutics, Inc. (“Sage” or the “Company”) is a biopharmaceutical company with a mission to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive. The Company’s product ZURZUVAE® (zuranolone) was approved by the U.S. Food and Drug Administration (the “FDA”) on August 4, 2023, for the treatment of postpartum depression (“PPD”) in adults. ZURZUVAE is a neuroactive steroid that is a positive allosteric modulator of GABAA receptors, targeting both synaptic and extrasynaptic GABAA receptors, and is the first oral, once-daily, 14-day treatment specifically indicated for adults with PPD. ZURZUVAE became commercially available for women with PPD in December 2023. The Company has a portfolio of product candidates with a current focus on modulating two critical central nervous system (“CNS”) receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of GABAA receptors. The NMDA-type receptors of the glutamate receptor system are a major excitatory receptor system in the CNS. Dysfunction in these systems is implicated in a broad range of CNS disorders. The Company is targeting diseases and disorders of the brain across its pipeline. The Company’s product ZULRESSO® (brexanolone) CIV injection was previously approved in the U.S. for the treatment of PPD in individuals 15 years old and older. The Company discontinued commercial availability of ZULRESSO as of December 31, 2024. In October 2024, the Company executed a plan to reorganize its business operations, including a reduction of approximately 33% of the Company’s total workforce and approximately 55% of the Company’s research and development workforce. See Note 11, Restructuring, for further details. On January 10, 2025, the Company received an unsolicited, non-binding acquisition proposal from Biogen MA Inc. (“BIMA”) and Biogen International GmbH (together with BIMA, “Biogen”) to acquire all outstanding shares of the Company not already owned by Biogen for $7.22 per share. On January 27, 2025, the Board of Directors of the Company (the “Board”) unanimously rejected the unsolicited, non-binding acquisition proposal received from Biogen. The Company further announced that the Board has initiated a process to explore strategic alternatives for the Company. The strategic review process is ongoing. The Company has not set a timetable for the review process nor have any decisions related to any potential strategic alternatives been made at this time. There can be no assurance that the strategic alternatives review process will result in any transaction or other strategic outcome. The Company was incorporated under the laws of the State of Delaware on April 16, 2010, and commenced operations on January 19, 2011, as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc. Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with the marketing and sale of pharmaceutical products; the potential for development by third parties of new technological innovations that may compete with the Company’s products and product candidates; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; the uncertainty of being able to secure additional capital when needed to fund operations; and the direct or indirect impacts of the macroeconomic environment and geopolitical events on its development activities, operations and financial condition. The product candidates developed by the Company require approvals from the FDA or foreign regulatory authorities prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that ZURZUVAE will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition. The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as the implementation of tariffs, inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events. Going Concern Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of March 31, 2025, the Company had an accumulated deficit of $3.0 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may need to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). The Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.

Sage Therapeutics, Inc. (“Sage” or the “Company”) is a biopharmaceutical company with a mission to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive.

The Company’s product ZURZUVAE® (zuranolone) was approved by the U.S. Food and Drug Administration (the “FDA”) on August 4, 2023, for the treatment of postpartum depression (“PPD”) in adults. ZURZUVAE is a neuroactive steroid that is a positive allosteric modulator of GABAA receptors, targeting both synaptic and extrasynaptic GABAA receptors, and is the first oral, once-daily, 14-day treatment specifically indicated for adults with PPD. ZURZUVAE became commercially available for women with PPD in December 2023.

The Company has a portfolio of product candidates with a current focus on modulating two critical central nervous system (“CNS”) receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of GABAA receptors. The NMDA-type receptors of the glutamate receptor system are a major excitatory receptor system in the CNS. Dysfunction in these systems is implicated in a broad range of CNS disorders. The Company is targeting diseases and disorders of the brain across its pipeline.

The Company’s product ZULRESSO® (brexanolone) CIV injection was previously approved in the U.S. for the treatment of PPD in individuals 15 years old and older. The Company discontinued commercial availability of ZULRESSO as of December 31, 2024.

In October 2024, the Company executed a plan to reorganize its business operations, including a reduction of approximately 33% of the Company’s total workforce and approximately 55% of the Company’s research and development workforce. See Note 11, Restructuring, for further details.

On January 10, 2025, the Company received an unsolicited, non-binding acquisition proposal from Biogen MA Inc. (“BIMA”) and Biogen International GmbH (together with BIMA, “Biogen”) to acquire all outstanding shares of the Company not already owned by Biogen for $7.22 per share. On January 27, 2025, the Board of Directors of the Company (the “Board”) unanimously rejected the unsolicited, non-binding acquisition proposal received from Biogen. The Company further announced that the Board has initiated a process to explore strategic alternatives for the Company. The strategic review process is ongoing. The Company has not set a timetable for the review process nor have any decisions related to any potential strategic alternatives been made at this time. There can be no assurance that the strategic alternatives review process will result in any transaction or other strategic outcome.

The Company was incorporated under the laws of the State of Delaware on April 16, 2010, and commenced operations on January 19, 2011, as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc.

Risks and Uncertainties

The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with the marketing and sale of pharmaceutical products; the potential for development by third parties of new technological innovations that may compete with the Company’s products and product candidates; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; the uncertainty of being able to secure additional capital

when needed to fund operations; and the direct or indirect impacts of the macroeconomic environment and geopolitical events on its development activities, operations and financial condition.

The product candidates developed by the Company require approvals from the FDA or foreign regulatory authorities prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that ZURZUVAE will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition.

The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as the implementation of tariffs, inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events.

Going Concern

Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of March 31, 2025, the Company had an accumulated deficit of $3.0 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may need to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself.

The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). The Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.