ARID1B

Topline Phase 1 dose escalation data for FHD-286 in combination with decitabine, in relapsed and/or refractory AML patients, anticipated in the fourth quarter of 2024 Dosing of first patient in a Phase 1 trial for FHD-909, a potential first-in-class SMARCA2 selective inhibitor, anticipated in the second half of 2024; primary target population in SMARCA4 mutated NSCLC IND-enabling studies for Selective CBP degrader program on track to begin by year-end 2024 Successful $110 million financing strengthens balance sheet with cash, cash equivalents and short-term investments of $285.2 million as of June 30, 2024 and extends expected cash runway into 2027 CAMBRIDGE, Mass., Aug. 08, 2024 (GLOBE NEWSWIRE) -- Foghorn® Therapeutics Inc. (Nasdaq: FHTX), a clinical-stage biotechnology company pioneering a new class of medicines that treat serious diseases by correcting abnormal gene expression, today provided a financial and corporate update in conjunction with the Company’s 10-Q filing for the quarter ended June 30, 2024. With an initial focus in oncology, Foghorn’s Gene Traffic Control® Platform and resulting broad pipeline have the potential to transform the lives of people suffering from a wide spectrum of diseases. “We anticipate topline data from our Phase 1 combination trial with FHD-286 in patients with relapsed and/or refractory AML in the fourth quarter of 2024. We believe FHD-286 has the potential to be a first-in-class, mutation-agnostic differentiation therapeutic,” said Adrian Gottschalk, President and Chief Executive Officer of Foghorn. “Additionally, the IND for FHD-909 cleared in May and we anticipate FHD-909 to be the first SMARCA2 selective inhibitor to enter the clinic. Dosing of the first patient in our Phase 1 trial, with primary target population in SMARCA4 mutated NSCLC, is planned for the second half of the year. We are also on track to initiate IND-enabling studies in the fourth quarter of 2024 for our Selective CBP degrader program targeting tumors harboring EP300 mutations including bladder, gastric and endometrial cancers.” Mr. Gottschalk continued, “The biological foundation for the development of therapeutics targeting the chromatin regulatory system in oncology and other disease areas continues to get stronger. In April, we were pleased to present preclinical data at AACR reinforcing the potential of our platform to deliver innovative medicines across cancers by selectively drugging historically very challenging targets. The conviction in our pipeline was further strengthened by our recent successful financing with new and long-term investors, which extended our expected cash runway into 2027 and through key inflection points, strongly positioning us for continued advancement.” Corporate Updates Strengthened Balance Sheet to Advance Pipeline. In May, Foghorn successfully closed an approximately $110 million registered direct offering to advance the Company’s pipeline. The offering included new investors BVF Partners, Deerfield Management and other leading healthcare specialist investors as well as current investors, including founding investor Flagship Pioneering. Presented at AACR Annual Meeting. In April, Foghorn presented preclinical data highlighting pipeline progress on the advancement of multiple potential first-in-class medicines, including the first presentation of preclinical data for FHD-909, at the 2024 American Association for Cancer Research (AACR) Annual Meeting. Hosted Chromatin Regulation Summit. In April, Foghorn hosted the first Future of Disease and Chromatin Regulation Summit at the Foghorn corporate headquarters in Cambridge, Massachusetts. The live event featured presentations and panel discussions with world-renowned industry and academic key opinion leaders on therapeutic opportunities in chromatin regulatory biology. Strengthened Executive Leadership. In April, Foghorn appointed Kristian Humer as Chief Financial Officer. Mr. Humer joined Foghorn with over 14 years of diversified financial strategy and business development experience in the life science industry and more than 20 years of experience in the financial industry. Key Recent Program Updates and Upcoming Milestones FHD-286. FHD-286 is a potent, first-in-class, selective inhibitor of the SMARCA2 (BRM) and SMARCA4 (BRG1) subunits of the BAF chromatin remodeling complex where dependency on SMARCA2/SMARCA4 is well-established preclinically with multiple tumor types, including acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS), non-small cell lung cancer (NSCLC) and prostate cancer. AML Phase 1 trial. The ongoing Phase 1 dose escalation trial is evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary clinical activity of FHD-286 in combination with decitabine or low-dose cytarabine in patients with relapsed and/or refractory AML who have failed multiple previous courses of therapy. FHD-286 previously demonstrated a promising mutation-agnostic differentiation effect in a single-agent dose escalation trial. Topline clinical data are anticipated in the fourth quarter. We anticipate this will include topline safety, tolerability, initial efficacy and PK/PD data. Overcoming Tyrosine Kinase Inhibitor Resistance. Data published in Cancer Cell in August 2023, together with additional preclinical studies conducted by Foghorn, suggest that FHD-286 may play an important role in overcoming resistance in EGFR/KRAS tumors. Preclinical data profiling the ability of FHD-286 to amplify and/or restore tumor sensitivity will be presented with FHD-286 Phase 1 dose escalation data. FHD-909. FHD-909 is a first-in-class oral SMARCA2 (BRM) selective inhibitor that has demonstrated in preclinical studies to have high selectivity over its closely related paralog SMARCA4 (BRG1), two proteins that are the catalytic engines across all forms of the BAF complex. SMARCA4 mutations are common across tumor types, including approximately 10% of NSCLC, and result in tumors being dependent on SMARCA2 activity for their survival. Selectively blocking SMARCA2 activity is a promising synthetic lethal strategy intended to induce tumor death while sparing healthy cells. In December 2021, Foghorn announced a strategic collaboration with Lilly to create novel oncology medicines. The collaboration includes a U.S. 50/50 co-development and co-commercialization agreement for Foghorn’s Selective SMARCA2 oncology program, which includes a selective inhibitor and a selective degrader, and an additional undisclosed oncology target. In addition, the collaboration includes three discovery programs using Foghorn’s proprietary Gene Traffic Control platform.In April 2024, Foghorn and Lilly presented new preclinical data as a poster presentation at the AACR Annual Meeting and during a pipeline update call demonstrating at tolerable doses high SMARCA2 selectivity and dose-dependent single agent activity in SMARCA4 mutated cancers.In May 2024, the investigational new drug (IND) application was approved by the Food and Drug Administration. The primary target patient population is SMARCA4 mutated NSCLC.Dosing of the first patient in the Phase 1 trial for FHD-909 is planned to begin in the second half of 2024. Selective CBP degrader program and Selective EP300 degrader program. Foghorn is advancing two separate programs targeting either CBP or EP300, paralog histone acetyltransferases with a synthetic lethal relationship in tumor cells. Attempts to selectively drug CBP or EP300 have been challenging due to the high level of similarity between the two proteins. Additionally, dual inhibition of CBP/EP300 has been historically limited by hematopoietic toxicity. Selective CBP degrader program. In April, Foghorn presented new pharmacodynamic and pharmacokinetic preclinical data at the 2024 AACR Annual Meeting and during a pipeline update call highlighting: Deep and sustained CBP degradation significantly inhibited tumor growth in mouse xenograft solid tumor models.Robust monotherapy preclinical anti-tumor activity that was not associated with significant body weight loss, thrombocytopenia or anemia.Identification of potent and selective CBP protein degraders with first-in-class potential to address tumors harboring EP300 mutations in many types of cancer, including bladder, gastric and endometrial cancers.IND-enabling studies on track to initiate by the fourth quarter of 2024. Selective EP300 degrader program. In April, Foghorn presented new pharmacodynamic and pharmacokinetic preclinical data at the 2024 AACR Annual Meeting and during a pipeline update call highlighting: Well-tolerated in vivo with no observed decrease in platelet levels, with no effects on megakaryocyte viability at pharmacologically relevant concentrations in ex vivo studies.Identification of potent and selective EP300 degraders with anti-tumor activity in prostate and hematological malignancies, including prostate cancer, multiple myeloma and diffuse large B cell lymphoma (DLBCL). Selective ARID1B degrader program. ARID1A is the most mutated subunit in the BAF Complex and amongst the most mutated proteins in oncology. These mutations lead to a dependency on ARID1B, in several types of cancer, including ovarian, endometrial, colorectal and bladder. Attempts to selectively drug ARID1B have been challenging because of the high degree of similarity between ARID1A and ARID1B and the fact that ARID1B has no enzymatic activity to target. In April, Foghorn presented data at the AACR Annual Meeting demonstrating potent and selective small molecule binders to ARID1B. The Company is in the process of converting these selective binders into heterobifunctional degraders. Second Quarter 2024 Financial Highlights Collaboration Revenues. Collaboration revenue was $6.9 million for the three months ended June 30, 2024, compared to $5.6 million for the three months ended June 30, 2023. The increase year-over-year was primarily driven by the continued advancement of programs under the Lilly Collaboration Agreement. Research and Development Expenses. Research and development expenses were $23.8 million for the three months ended June 30, 2024, compared to $29.2 million for the three months ended June 30, 2023. This decrease was primarily due to lower personnel-related costs and lower development program spend following the shutdown of two clinical studies (FHD-286 in metastatic uveal melanoma and FHD-609 (BRD9 degrader) in synovial sarcoma). General and Administrative Expenses. General and administrative expenses were $7.3 million for the three months ended June 30, 2024, compared to $8.4 million for the three months ended June 30, 2023. This decrease was primarily due to lower personnel-related costs. Net Loss. Net loss was $23.0 million for the three months ended June 30, 2024, compared to a net loss of $29.5 million for the three months ended June 30, 2023. Cash, Cash Equivalents and Marketable Securities. As of June 30, 2024, the Company had $285.2 million in cash, cash equivalents and marketable securities, providing expected cash runway into 2027. About FHD-286 FHD-286 is a highly potent, first-in-class, selective, allosteric, and orally available small-molecule, enzymatic inhibitor of SMARCA2 (BRM) and SMARCA4 (BRG1), two highly similar proteins that are the ATPases, or the catalytic engines, of the BAF complex, one of the key regulators within the chromatin regulatory system. In preclinical studies, FHD-286 has shown anti-tumor activity across a broad range of malignancies including both hematologic and solid tumors. About AMLAdult acute myeloid leukemia (AML) is a cancer of the blood and bone marrow and the most common type of acute leukemia in adults. AML is a diverse disease associated with multiple genetic mutations. It is diagnosed in about 20,000 people every year in the United States. About FHD-909FHD-909 (LY4050784) is a potent, first-in-class, allosteric and orally available small molecule that selectively inhibits the ATPase activity of SMARCA2 (BRM) over its closely related paralog SMARCA4 (BRG1), two proteins that are the catalytic engines across all forms of the BAF complex, one of the key regulators of the chromatin regulatory system. In preclinical studies, tumors with mutations in SMARCA4 rely on SMARCA2 for BAF function. FHD-909 has shown significant anti-tumor activity across multiple SMARCA4-mutant lung tumor models. About Foghorn TherapeuticsFoghorn® Therapeutics is discovering and developing a novel class of medicines targeting genetically determined dependencies within the chromatin regulatory system. Through its proprietary scalable Gene Traffic Control® platform, Foghorn is systematically studying, identifying and validating potential drug targets within the chromatin regulatory system. The Company is developing multiple product candidates in oncology. Visit our website at www.foghorntx.com for more information on the Company, and follow us on X (formerly Twitter) and LinkedIn. Forward-Looking StatementsThis press release contains “forward-looking statements.” Forward-looking statements include statements regarding the Company’s clinical trials, including its ongoing Phase 1 study of FHD-286 in combination with decitabine in relapsed and/or refractory AML patients and the planned Phase 1 trial of FHD-909, pre-clinical product candidates, expected timing of clinical data, expected cash runway, expected timing of regulatory filings, and research efforts and other statements identified by words such as “could,” “may,” “might,” “will,” “likely,” “anticipates,” “intends,” “plans,” “seeks,” “believes,” “estimates,” “expects,” “continues,” “projects” and similar references to future periods. Forward-looking statements are based on our current expectations and assumptions regarding capital market conditions, our business, the economy and other future conditions. Because forward-looking statements relate to the future, by their nature, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. As a result, actual results may differ materially from those contemplated by the forward-looking statements. Important factors that could cause actual results to differ materially from those in the forward-looking statements include regional, national or global political, economic, business, competitive, market and regulatory conditions, including risks relating to our clinical trials and other factors set forth under the heading “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the Securities and Exchange Commission. Any forward-looking statement made in this press release speaks only as of the date on which it is made. Condensed Consolidated Balance Sheets(In thousands) June 30, 2024 December 31, 2023Cash, cash equivalents and marketable securities$285,177 $234,057 All other assets 43,408 51,859 Total assets$328,585 $285,916 Deferred revenue, total$290,726 $302,665 All other liabilities 52,181 60,441 Total liabilities$342,907 $363,106 Total stockholders’ deficit$(14,322) $(77,190)Total liabilities and stockholders’ deficit$328,585 $285,916 Condensed Consolidated Statements of Operations(In thousands, except share and per share amounts) Three Months Ended June 30, 2024 2023 Collaboration revenue$6,888 $5,599 Operating expenses: Research and development 23,797 29,248 General and administrative 7,325 8,401 Impairment of long-lived assets 2,398 — Total operating expenses$33,520 $37,649 Loss from operations$(26,632) $(32,050)Total other income, net$3,653 $3,505 Provision for income taxes$— $(942)Net loss$(22,979) $(29,487)Net loss per share attributable to common stockholders—basic and diluted (0.45) (0.70)Weighted average common shares outstanding—basic and diluted 51,580,310 41,825,555 Contacts:Karin Hellsvik, Foghorn Therapeutics Inc. (Investors & Media)khellsvik@foghorntx.com Adam Silverstein, ScientPR (Media)adam@scientpr.com Peter Kelleher, LifeSci Advisors (Investors)pkelleher@lifesciadvisors.com

Dose escalation in FHD-286 combination trial in AML continues to progress with clinical data expected in the second half of 2024; potential to be a first-in-class oral broad-based differentiation therapeutic in AML IND filing submitted for FHD-909, a first-in-class oral BRM (SMARCA2) selective inhibitor; Phase 1 trial planned to begin in the second half of 2024 with primary target population in BRG1 mutated non-small cell lung cancer; first BRM selective inhibitor to enter the clinic IND-enabling studies for Selective CBP degrader program on track to begin by year-end 2024 Data presented at AACR support monotherapy activity and first-in-class potential for historically challenging targets including FHD-909, Selective CBP degrader and Selective EP300 degrader programs Cash, cash equivalents, and marketable securities of $206.7 million, as of March 31, 2024, providing cash runway into the first half of 2026 CAMBRIDGE, Mass., May 06, 2024 (GLOBE NEWSWIRE) -- Foghorn® Therapeutics Inc. (Nasdaq: FHTX), a clinical-stage biotechnology company pioneering a new class of medicines that treat serious diseases by correcting abnormal gene expression, today provided a financial and corporate update in conjunction with the Company’s 10-Q filing for the quarter ended March 31, 2024. With an initial focus in oncology, Foghorn’s Gene Traffic Control® Platform and resulting broad pipeline have the potential to transform the lives of people suffering from a wide spectrum of diseases. “We are excited about the progress and strength of data presented this quarter which includes robust preclinical anti-tumor monotherapy activity at tolerable doses for multiple pipeline programs. We believe these data demonstrate the potential of our platform to generate novel medicines against very challenging targets, as well as our leadership in the development of therapeutics in chromatin biology," said Adrian Gottschalk, President and Chief Executive Officer of Foghorn. Mr. Gottschalk added, “In the second half of the year, we expect initial data from our FHD-286 combination study in AML. The IND for FHD-909 was recently submitted and would be the first selective BRM inhibitor to enter the clinic, with a Phase 1 trial planned to begin in the second half of this year. Earlier this year, we also shared data from our Selective CBP degrader program demonstrating tumor growth inhibition in solid tumors without thrombocytopenia or anemia that have been observed with dual CBP/EP300 inhibition. Our Selective EP300 degrader program also demonstrated promising preclinical efficacy with no thrombocytopenia, which is often seen in dual approaches. Our cash balance remains strong, and with multiple programs advancing, we are expected to deliver near- and mid-term value for both patients and shareholders.” Corporate Updates Presented at AACR Annual Meeting. In April 2024, Foghorn presented preclinical data highlighting pipeline progress from multiple potential first-in-class medicines, including the first presentation of preclinical data for FHD-909, at the 2024 American Association for Cancer Research (AACR) Annual Meeting held April 5-10, 2024. Hosted Chromatin Regulation Summit. In April 2024, Foghorn hosted the first Future of Disease and Chromatin Regulation Summit at the Foghorn corporate headquarters in Cambridge, Massachusetts. The live event featured presentations and panel discussions with world-renowned industry and academic key opinion leaders on therapeutic opportunities in chromatin regulatory biology. Strengthened Financial Leadership. In April 2024, Foghorn appointed Kristian Humer as Chief Financial Officer. Mr. Humer joins Foghorn with over 14 years of diversified financial strategy and business development experience in the life science industry and more than 20 years of experience in the financial industry. Key Recent Program Updates and Upcoming Milestones FHD-286. FHD-286 is a potent, selective inhibitor of the BRG1 (SMARCA4) and BRM (SMARCA2) subunits of the BAF chromatin remodeling complex where dependency on BRG1/BRM is well-established preclinically with multiple tumor types, including acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS), non-small cell lung cancer (NSCLC) and prostate cancer. AML Update. Foghorn initiated a Phase 1 trial of FHD-286 in combination with decitabine or low-dose cytarabine (LDAC) in relapsed and/or refractory AML patients, with the first patient dosed during the third quarter of 2023. Dose escalation is ongoing with initial clinical data expected in the second half of 2024 . Tyrosine Kinase Inhibitor Resistance. Data published in Cancer Cell in August 2023, along with Foghorn’s work, suggest that FHD-286 may play an important role in overcoming and delaying resistance in EGFR/KRAS tumors. Preclinical data is expected in the second quarter of 2024. FHD-909. FHD-909 is a first-in-class oral BRM (SMARCA2) selective inhibitor that has been demonstrated in preclinical studies to have high selectivity over its closely related paralog BRG1 (SMARCA4), two proteins that are the catalytic engines across all forms of the BAF complex. BRG1 mutations are common across tumor types, including approximately 10% of NSCLC, and result in tumors being dependent on BRM activity for their survival. Selectively blocking BRM activity is a promising synthetic lethal strategy intended to induce tumor death while sparing healthy cells. In December 2021, Foghorn announced a strategic collaboration with Lilly to create novel oncology medicines. The collaboration includes a US 50/50 co-development and co-commercialization agreement for Foghorn’s Selective BRM oncology program and an additional undisclosed oncology target. In addition, the collaboration includes three discovery programs using Foghorn’s proprietary Gene Traffic Control platform. In the first quarter of 2024, Lilly selected FHD-909 for clinical development and in April the investigational new drug (IND) application was submitted. The primary target patient population is BRG1-mutated NSCLC. In April 2024, Foghorn and Lilly presented new preclinical data as a poster presentation at the AACR Annual Meeting demonstrating, at tolerable doses, high BRM selectivity and dose-dependent single agent activity in BRG1-mutated cancers. Dosing of first patient in Phase 1 trial for FHD-909 in BRG1-mutated NSCLC is expected in the second half of 2024. Selective CBP Degrader Program and Selective EP300 Degrader Program. Foghorn is advancing two separate programs targeting either CBP or EP300, both of which are paralog histone acetyltransferases with a synthetic lethal relationship in tumor cells. Attempts to selectively drug CBP or EP300 have been historically challenging due to the high level of similarity between the two proteins. Additionally, dual inhibition of CBP/EP300 is limited by hematopoietic toxicity. Selective CBP Degrader Program. In April, Foghorn presented new pharmacodynamic and pharmacokinetic preclinical data at the 2024 AACR Annual Meeting highlighting: Deep and sustained CBP degradation significantly inhibited tumor growth in mouse xenograft solid tumor models. Robust monotherapy preclinical anti-tumor activity that was not associated with significant body weight loss, thrombocytopenia or anemia. Identification of potent and selective CBP protein degraders with first-in-class potential to address tumors harboring EP300 mutations in many types of cancer, including bladder, gastric and endometrial cancers. Long-acting CBP-selective protein degrader formulations with first-in-class potential for patients with tumors harboring EP300 mutations. IND-enabling studies on track to initiate by year-end 2024. Selective EP300 Degrader Program. In April, Foghorn presented new pharmacodynamic and pharmacokinetic preclinical data at the 2024 AACR Annual Meeting highlighting: No observed thrombocytopenia in vivo. Identification of potent and selective EP300 protein degraders with first-in-class potential to address tumors harboring CBP mutations and tumors with dependency on EP300 in several types of cancer, including prostate, multiple myeloma and diffuse large B cell lymphoma (DLBCL). Selective ARID1B Degrader Program. ARID1A is the most mutated subunit in the BAF Complex and amongst the most mutated proteins in oncology. These mutations lead to a dependency on ARID1B, in several types of cancer, including ovarian, endometrial, colorectal and bladder. Attempts to selectively drug ARID1B have been challenging because of the high degree of similarity between ARID1A and ARID1B and the fact that ARID1B has no enzymatic activity to target. In April, Foghorn presented data at the AACR Annual Meeting demonstrating potent and selective small molecule binders to ARID1B. The Company is in the process of converting these selective binders into heterobifunctional degraders. Drug Discovery Platform. Foghorn's synthesis of deep chromatin expertise, protein biochemistry and screening, and degrader expertise uniquely positions the Company to successfully drug historically challenging targets. Potential for five additional INDs in the next four years. Targets combined have the potential to address more than 20 tumor types impacting over 500,000 new patients annually. First Quarter 2024 Financial Highlights Collaboration Revenues. Collaboration revenue was $5.1 million for the three months ended March 31, 2024, compared to $5.3 million for the three months ended March 31, 2023. The decrease year-over-year was primarily driven by the termination of the Merck collaboration agreement. Research and Development Expenses. Research and development expenses were $25.5 million for the three months ended March 31, 2024, compared to $30.0 million for the three months ended March 31, 2023. This decrease was primarily due to lower personnel-related costs. General and Administrative Expenses. General and administrative expenses were $7.7 million for the three months ended March 31, 2024, compared to $8.6 million for the three months ended March 31, 2023. This decrease was primarily due to lower personnel-related costs. Net Loss. Net loss was $25.0 million for the three months ended March 31, 2024, compared to a net loss of $30.5 million for the three months ended March 31, 2023. Cash, Cash Equivalents and Marketable Securities. As of March 31, 2024, the Company had $206.7 million in cash, cash equivalents and marketable securities, which providing expected cash runway into the first half of 2026. About FHD-286 FHD-286 is a potent, selective, allosteric, and orally available small-molecule, enzymatic inhibitor of BRG1 (SMARCA4) and BRM (SMARCA2), two highly similar proteins that are the ATPases, or the catalytic engines, of the BAF complex, one of the key regulators within the chromatin regulatory system. In preclinical studies, FHD-286 has shown anti-tumor activity across a broad range of malignancies including both hematologic and solid tumors. About AML Adult acute myeloid leukemia (AML) is a cancer of the blood and bone marrow and the most common type of acute leukemia in adults. AML is a diverse disease associated with multiple genetic mutations. It is diagnosed in about 20,000 people every year in the United States. About FHD-909 FHD-909 (a.k.a. LY4050784) is a potent, allosteric and orally available small molecule that selectively inhibits the ATPase activity of BRM (SMARCA2) over its closely related paralog BRG1 (SMARCA4), two proteins that are the catalytic engines across all forms of the BAF complex, one of the key regulators of the chromatin regulatory system. In preclinical studies, tumors with mutations in BRG1 rely on BRM for BAF function. FHD-909 has shown significant anti-tumor activity across multiple BRG1-mutant lung tumor models. About Foghorn Therapeutics Foghorn® Therapeutics is discovering and developing a novel class of medicines targeting genetically determined dependencies within the chromatin regulatory system. Through its proprietary scalable Gene Traffic Control® platform, Foghorn is systematically studying, identifying and validating potential drug targets within the chromatin regulatory system. The Company is developing multiple product candidates in oncology. Visit our website at for more information on the Company, and follow us on X (formerly Twitter) and LinkedIn. Forward-Looking Statements This press release contains “forward-looking statements.” Forward-looking statements include statements regarding the Company’s clinical trials, including its ongoing Phase 1 study of FHD-286 in combination with decitabine or low-dose cytarabine (LDAC) in relapsed and/or refractory AML patients, pre-clinical product candidates, including the planned Phase 1 study of FHD-909, expected timing of clinical data, expected timing of regulatory filings, and research efforts and other statements identified by words such as “could,” “may,” “might,” “will,” “likely,” “anticipates,” “intends,” “plans,” “seeks,” “believes,” “estimates,” “expects,” “continues,” “projects” and similar references to future periods. Forward-looking statements are based on our current expectations and assumptions regarding capital market conditions, our business, the economy and other future conditions. Because forward-looking statements relate to the future, by their nature, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. As a result, actual results may differ materially from those contemplated by the forward-looking statements. Important factors that could cause actual results to differ materially from those in the forward-looking statements include regional, national or global political, economic, business, competitive, market and regulatory conditions, including risks relating to our clinical trials and other factors set forth under the heading “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the Securities and Exchange Commission. Any forward-looking statement made in this press release speaks only as of the date on which it is made. Condensed Consolidated Balance Sheets (In thousands) March 31, 2024 December 31, 2023 Cash, cash equivalents and marketable securities $ 206,661 $ 234,057 All other assets 48,343 51,859 Total assets $ 255,004 $ 285,916 Deferred revenue, total $ 297,615 $ 302,665 All other liabilities 54,875 60,441 Total liabilities $ 352,490 $ 363,106 Total stockholders’ equity (deficit) $ (97,486 ) $ (77,190 ) Total liabilities and stockholders’ equity $ 255,004 $ 285,916 Condensed Consolidated Statements of Operations (In thousands, except share and per share amounts) Three Months Ended March 31, 2024 2023 Collaboration revenue $ 5,050 $ 5,309 Operating expenses: Research and development 25,534 29,985 General and administrative 7,710 8,641 Total operating expenses $ 33,244 $ 38,626 Loss from operations $ (28,194 ) $ (33,317 ) Total other income, net $ 3,178 $ 3,389 Provision for income taxes $ — $ (560 ) Net loss $ (25,016 ) $ (30,488 ) Net loss per share attributable to common stockholders—basic and diluted (0.59 ) (0.73 ) Weighted average common shares outstanding—basic and diluted 42,428,813 41,811,087 Contacts: Greg Dearborn, Foghorn Therapeutics Inc. (Investors) gdearborn@foghorntx.com Karin Hellsvik, Foghorn Therapeutics Inc. (Investors & Media) khellsvik@foghorntx.com Adam Silverstein, ScientPR (Media) adam@scientpr.com Peter Kelleher, LifeSci Advisors (Investors) pkelleher@lifesciadvisors.com

• Dose escalation in FHD-286 combination study in AML continues to progress; clinical data anticipated in the second half of 2024 • FHD-909, a first-in-class BRM selective inhibitor, selected for clinical development by partner Lilly; preclinical data to be presented at AACR with IND planned for the second quarter, primary target patient population in non-small cell lung cancer • Selective CBP and EP300 degrader preclinical data to be presented at AACR; IND-enabling studies for CBP degrader program planned to begin by end of 2024 • Foghorn anticipates at least six new INDs targeting significant oncology patient populations over the next four years, reflecting the continued productivity of its precision medicine platform • Cash, cash equivalents, and marketable securities of $234.1 million, as of December 31, 2023, provide cash runway into the first half of 2026 CAMBRIDGE, Mass., March 07, 2024 (GLOBE NEWSWIRE) -- Foghorn® Therapeutics Inc. (Nasdaq: FHTX), a clinical-stage biotechnology company pioneering a new class of medicines that treat serious diseases by correcting abnormal gene expression, today provided a financial update and corporate outlook in conjunction with the Company’s 10-K filing for the year ending December 31, 2023. With an initial focus in oncology, Foghorn’s Gene Traffic Control® Platform and resulting broad pipeline have the potential to transform the lives of people with a wide spectrum of diseases. “The research and clinical advances we made in 2023 set the stage for Foghorn to deliver significant value with the potential for several differentiated, high-impact medicines in 2024 and beyond,” said Adrian Gottschalk, President and Chief Executive Officer of Foghorn. “In 2023 we initiated a combination study with FHD-286 in AML, with data anticipated in the second half of 2024. Based on the mutation-agnostic differentiation effect observed in our single-agent escalation study, we believe FHD-286 has the potential to be a first-in-class broad-based differentiation therapeutic in AML. We are also making progress with our selective BRM program with FHD-909, a first-in-class BRM selective inhibitor, selected for clinical development by partner Lilly. The IND is planned for the second quarter of 2024, with an initial focus in non-small cell lung cancer. Finally, we are excited by the preclinical efficacy and safety data for our CBP and EP300 selective degrader programs and target IND-enabling studies for CBP by the end of the year. Our cash position remains strong with runway into the first half of 2026.” Key Recent Updates and Upcoming Milestones FHD-286. FHD-286 is a potent, selective inhibitor of the BRG1 and BRM subunits of the BAF chromatin remodeling complex where dependency on BRG1/BRM is well-established preclinically with multiple tumor types, including acute myelogenous leukemia (AML)/myelodysplastic syndrome (MDS), non-small cell lung cancer (NSCLC) and prostate cancer. AML Update. Foghorn commenced a Phase 1 study of FHD-286 in combination with decitabine or low-dose cytarabine (LDAC) in relapsed and/or refractory AML patients, with the first patient dosed during the third quarter of 2023. Dose escalation is ongoing, and the first clinical data are expected in the second half of 2024.TKI Resistance. Recently published data, along with Foghorn’s work, suggest that FHD-286 may play an important role in overcoming resistance in EGFR/KRAS tumors. The Company is conducting preclinical work to further explore the opportunity and expects data in the second quarter of 2024. Differentiated Pipeline Advancement. Foghorn continues to expand its platform and pipeline. The Company anticipates the potential for six new investigational new drug (IND) applications in the next four years. The Company continues to progress programs for multiple targets that include chromatin remodeling complexes, transcription factors, helicases, and other chromatin-related factors. These targets include selective BRM and wholly owned programs including CBP, EP300, and ARID1B, as well as other undisclosed targets, which combined could address more than 20 tumor types impacting more than 500,000 new patients annually. Selective CBP and Selective EP300 programs. Foghorn is presenting new preclinical data for its CBP and EP300 selective degrader programs at the 2024 AACR Annual Meeting, April 5-10, 2024. CBP selective degraders have shown significant tumor growth inhibition in a colorectal cancer in vivo model. Antiproliferative effects were also observed for numerous cancer cell lines, including colorectal, gastric and bladder cancers.EP300 selective degraders have shown potent cellular antiproliferation and in vivo tumor growth inhibition in an AR+ enzalutamide prostate in vivo model.At preclinical efficacious doses, neither the CBP nor the EP300 selective degraders cause thrombocytopenia, a commonly observed safety liability for dual CBP/EP300 inhibitors. Lilly Collaboration. Foghorn is engaged in a strategic collaboration with Lilly and continues to advance the BRM selective inhibitor and degrader programs along with other undisclosed programs. In the first quarter of 2024, Lilly selected FHD-909, a first-in-class oral BRM selective inhibitor, for clinical development. Lilly plans to file an IND for FHD-909 in the second quarter of 2024. The primary target patient population is BRG1-mutated NSCLC.Selective BRM inhibition has been a sought-after objective in cancer research for many years. A variety of tumor types, including NSCLC, are known to have mutations in BRG1, which we believe make them dependent on BRM activity for their survival. Selective blocking of BRM activity is considered a promising strategy for causing tumor cell death while sparing healthy cells.Preclinical data will be presented in 2024, including at AACR with a poster presentation on April 8. In December 2021, Foghorn announced a strategic collaboration with Lilly to create novel oncology medicines. The collaboration includes a co-development and co-commercialization agreement for Foghorn’s Selective BRM oncology program and an additional undisclosed oncology target. In addition, the collaboration includes three discovery programs using Foghorn’s proprietary Gene Traffic Control platform. Full Year 2023 Financial Highlights Collaboration Revenues. Collaboration revenues were $34.2 million for the year ended December 31, 2023, compared to $19.2 million for the year ended December 31, 2022. The increase year-over-year was primarily driven by revenue recognized under the Merck collaboration due to the termination of the agreement and the subsequent recognition of the remaining deferred revenue.Research and Development Expenses. Research and development expenses were $109.7 million for the year ended December 31, 2023, compared to $105.6 million for the year ended December 31, 2022. This increase was primarily due to costs associated with continued investment in R&D personnel, platform, and other early-stage research, partially offset by a decrease in spend on FHD-286 and FHD-609.General and Administrative Expenses. General and administrative expenses were $32.4 million for the year ended December 31, 2023, compared to $30.7 million for the year ended December 31, 2022. This increase was primarily due to an increase in investments to support the growing business, which included increases in personnel-related costs and stock-based compensation expense.Net Loss. Net loss was $98.4 million for the year ended December 31, 2023, compared to a net loss of $108.9 million for the year ended December 31, 2022.Cash, cash equivalents and marketable securities. As of December 31, 2023, the Company had $234.1 million in cash, cash equivalents and marketable securities, providing cash runway into the first half of 2026. About FHD-286 FHD-286 is a highly potent, selective, allosteric, and orally available small-molecule, enzymatic inhibitor of BRG1 (SMARCA4) and BRM (SMARCA2), two highly similar proteins that are the ATPases, or the catalytic engines, of the BAF complex, one of the key regulators within the chromatin regulatory system. In preclinical studies, FHD-286 has shown anti-tumor activity across a broad range of malignancies including both hematologic and solid tumors. About AMLAdult acute myeloid leukemia (AML) is a cancer of the blood and bone marrow and the most common type of acute leukemia in adults. AML is a diverse disease associated with multiple genetic mutations. It is diagnosed in about 20,000 people every year in the United States. About FHD-909FHD-909 (a.k.a. LY4050784) is a highly potent, allosteric and orally available small molecule that selectively inhibits the ATPase activity of BRM (SMARCA2) over its closely related paralog BRG1 (SMARCA4), two proteins that are the catalytic engines across all forms of the BAF complex, one of the key regulators of the chromatin regulatory system. In preclinical studies, tumors with mutations in BRG1 rely on BRM for BAF function. FHD-909 has shown significant anti-tumor activity across multiple BRG1-mutant lung tumors. About Foghorn TherapeuticsFoghorn® Therapeutics is discovering and developing a novel class of medicines targeting genetically determined dependencies within the chromatin regulatory system. Through its proprietary scalable Gene Traffic Control® platform, Foghorn is systematically studying, identifying and validating potential drug targets within the chromatin regulatory system. The Company is developing multiple product candidates in oncology. Visit our website at www.foghorntx.com for more information on the company and follow us on X (formerly Twitter) and LinkedIn.Forward-Looking StatementsThis press release contains “forward-looking statements.” Forward-looking statements include statements regarding the Company’s clinical trials, product candidates and research efforts and other statements identified by words such as “could,” “may,” “might,” “will,” “likely,” “anticipates,” “intends,” “plans,” “seeks,” “believes,” “estimates,” “expects,” “continues,” “projects” and similar references to future periods. Forward-looking statements are based on our current expectations and assumptions regarding capital market conditions, our business, the economy and other future conditions. Because forward-looking statements relate to the future, by their nature, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. As a result, actual results may differ materially from those contemplated by the forward-looking statements. Important factors that could cause actual results to differ materially from those in the forward-looking statements include regional, national or global political, economic, business, competitive, market and regulatory conditions, including risks relating to our clinical trials and other factors set forth under the heading “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the Securities and Exchange Commission. Any forward-looking statement made in this press release speaks only as of the date on which it is made. Condensed Consolidated Balance Sheets(In thousands) Dec. 31, 2023 Dec. 31, 2022Cash, cash equivalents and marketable securities$234,057 $345,798Collaboration receivable — —All other assets 51,859 59,085Total assets$285,916 $404,883Deferred revenue, total$302,665 $336,820All other liabilities 60,441 67,951Total liabilities 363,106 404,771Total stockholders’ equity (77,190) 112Total liabilities and stockholders’ equity$285,916 $404,883 Condensed Consolidated Statements of Operations(In thousands, except share and per share amounts) Twelve Months Ended December 31, 2023 2022 Collaboration revenue$34,155 $19,228 Operating expenses: Research and development 109,689 105,618 General and administrative 32,372 30,747 Total operating expenses 142,061 136,365 Loss from operations (107,906) (117,137)Total other income, net 13,706 8,255 Loss before income taxes (94,200) (108,882)Provision for income taxes (4,226) — Net loss$(98,426) $(108,882)Net loss per share attributable to common stockholders—basic and diluted$(2.34) $(2.62)Weighted average common shares outstanding—basic and diluted 41,974,484 41,591,433 Contacts:Greg Dearborn, Foghorn Therapeutics Inc. (Investors) gdearborn@foghorntx.com Karin Hellsvik, Foghorn Therapeutics Inc. (Investors and Media) khellsvik@foghorntx.com Adam Silverstein, ScientPR (Media) adam@scientpr.com Peter Kelleher, LifeSci Advisors (Investors) pkelleher@lifesciadvisors.com