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– Proceeds will fund advancement of ARON degrader, FX-111, to proof of concept and preclinical development of ARON RIPTAC program
– Veteran biotech executive, Anna Protopapas, appointed as CEO to guide company through next phase of growth focused on prostate cancer
Cambridge, MA, June 30, 2026 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover and develop precision medicines, today announced the closing of an $85 million Series C financing led by existing investors. In connection with the financing, the company also announced the appointment of Anna Protopapas as Chief Executive Officer.
The financing was led by Third Rock Ventures and Nextech Invest and included participation from Pfizer Ventures, Boxer Capital, GordonMD Global Investments® LP, Invus, Casdin Capital, Eli Lilly and Company, Novartis, Agent Capital and Eventide Asset Management. Proceeds from the financing will be used to advance the Company’s prioritized programs, as well as for working capital and general corporate purposes.
Pipeline Prioritization
In connection with the financing, the Company has completed a strategic review of its pipeline and will concentrate resources on FX-111, a first-in-class, highly differentiated, potent and selective degrader targeting ARON, the transcriptionally active, hormone-bound androgen receptor for prostate cancer. By targeting ARON, FX-111 has the potential to overcome the key resistance mechanisms that limit conventional therapies directed at AROFF, particularly in high-risk AR-driven disease, with broad applicability across all stages of AR-driven disease. The Company received Investigational New Drug (IND) clearance from the U.S. Food and Drug Administration (FDA) and expects to initiate clinical development in the third quarter of 2026. FlareTx is also advancing an ARON Regulated Induced Proximity Targeting Chimeras (RIPTAC) program through preclinical development. This program complements FX-111 and further expands the Company’s ability to address prostate cancer across the full disease continuum.
“At Nextech, we focus capital where we see the strongest scientific and clinical conviction,” said Kanishka Pothula, Managing Partner at Nextech Invest. “We believe FlareTx’s ARON-targeting approach is highly differentiated and has the potential to address important limitations of current prostate cancer therapies. This financing reflects our continued conviction in the team, the platform, and the potential of FX-111 to become an important therapy for patients with AR-driven prostate cancer.”
“Our continued support of FlareTx into this next phase of growth is a testament to the differentiated transcription factor platform that has advanced novel programs into the clinic with potentially transformational impact to patients,” said Abbie Celniker PhD, FlareTx founder and Partner at Third Rock Ventures. “We are also very pleased to welcome Anna Protopapas as incoming CEO. Her proven track record of leadership in oncology, spanning global development through commercialization, makes her exceptionally well suited to lead the Company.”
FX-909, a first-in-class, orally available PPARG inhibitor targeting the luminal lineage biology underlying urothelial cancer, is currently being evaluated in a Phase 1B dose expansion study. The Company intends to advance this program through an external partnership to fully realize its potential, including opportunities to explore combination regimens and earlier lines of therapy where luminal lineage biology plays a defining role.
“This is an exciting time for Flare Therapeutics and for patients with prostate cancer who desperately need new options. FX-111 offers a new approach to targeting the androgen receptor pathway that has the potential to transform prostate cancer treatment across all stages of disease, while avoiding mechanisms of resistance, representing a genuinely differentiated opportunity,” said Anna Protopapas, incoming Chief Executive Officer. “I am thrilled to lead a team that has proven it can advance a platform focused on drugging transcription factors and look forward to demonstrating that potential as we initiate our Phase 1A clinical study for FX-111 in the coming weeks.”
CEO Appointment
Anna Protopapas joined the board of Flare Therapeutics in February 2025 and became Chair in September 2025. Most recently, Ms. Protopapas served as President and Chief Executive Officer of Mersana Therapeutics from 2015 until September 2023, where she led advancement of the company’s ADC platforms and pipeline, transitioning the company to a publicly traded entity and raised significant capital through partnerships and equity financing. Prior to Mersana, Ms. Protopapas was President of Millennium, a wholly owned subsidiary of Takeda, where she led Takeda’s oncology business. Ms. Protopapas also served as Executive Vice President of Global Business Development at Takeda, where she led acquisitions and partnerships that helped catalyze Takeda’s growth and globalization. Earlier, Ms. Protopapas was an executive officer at Millennium and served in various senior leadership positions, playing an integral role in the company’s transformation from a genomics start-up to a fully integrated oncology leader and the subsequent acquisition of the company by Takeda. Ms. Protopapas has served as the Chair of the Board at Nuvalent since early 2022 (recently announced to be acquired by GSK for $10.6B) and previously served on the boards of ARIAD Pharmaceuticals (acquired by Takeda), Bioverativ (acquired by Sanofi) and Dicerna (acquired by Novo Nordisk) and Mersana Therapeutics (acquired by Day One). She received her B.S. in Science and Engineering from Princeton University, M.S. in Chemical Engineering Practice from the Massachusetts Institute of Technology and M.B.A. from Stanford Graduate School of Business.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s development portfolio targeting transcription factors involved in oncology leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors
Sarah McCabe
investorrelations@flaretx.com
Media
Cambridge, MA, April 6, 2026 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced that it will present three posters at the upcoming American Association for Cancer Research (AACR) Annual Meeting 2026, which is being held from April 17-22, 2026, in San Diego, CA.
The poster presentations will include preclinical data for the company’s two lead programs, FX-909, a first-in-class, orally available PPARG inhibitor designed to target the underlying luminal lineage biology of urothelial cancer and FX-111, a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor for prostate cancer.
FX-909 Presentation Details:
Luminal urothelial carcinoma (UC), characterized by high PPARG expression, represents the majority of UC cases and is associated with poor clinical outcomes. In a Phase 0 study, FX-909, a first-in-class oral PPARG inhibitor, demonstrated intratumoral penetration and on-target activity, including dose-dependent PPARG modulation, increased tumor apoptosis, and enhanced CD8⁺ T-cell infiltration. Notably, combination with anti-PD-1 further amplified immune activation and suppression of tumor proliferation pathways. These findings support the potential of FX-909 to modulate the tumor microenvironment and warrant further clinical evaluation in UC.
Title: Phase 0 Intratumoral Microdevice Study of FX-909 in Bladder Cancer Demonstrates On-Target Anti-Tumor Activity and Immune Modulation, Enhanced in Combination with Anti-PD-1
FX-111 Presentation Details:
Metastatic castration-resistant prostate cancer (mCRPC) remains largely driven by androgen receptor (AR) signaling, with resistance to current AR inhibitors posing a major clinical challenge. Real-world data identified distinct AR/KLK3-defined subgroups, with AR copy number amplification linked to increased AR signaling and poorer outcomes, reinforcing the central role of AR-driven biology in disease progression and identifying a high-risk, AR-driven population.
Title: AR copy number amplification and AR/KLK3 expression patterns reveal mechanisms of AR signaling inhibitor (ARSI) resistance and highlight the need for AR-directed therapeutic innovation in metastatic castration resistance prostate cancer (mCRPC)
FX-111 is a novel and highly differentiated, potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF, particularly in high-risk AR-driven disease, and has broad potential across prostate cancer at all stages.
Title: Discovery of FX-111, a first-in-class heterobifunctional degrader of transcriptionally active androgen receptor (ARON), to treat patients with AR-driven prostate cancer
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, a master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
investorrelations@flaretx.com
Media:
Timothy Cockroft
media@flaretx.com
– Data support emergence of differentiating clinical benefit with a favorable safety and tolerability profile for patients with advanced UC
Cambridge, MA, Feb. 27, 2026 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced the presentation of updated clinical data and associated biomarkers from the Phase 1A study of FX-909, a first-in-class orally bioavailable potent and selective small molecule inhibitor of peroxisome proliferator-activated receptor gamma (PPARG), a master regulator of the luminal lineage, in locally-advanced or metastatic urothelial cancer (UC).
Matthew Galsky, M.D., FASCO, Professor of Medicine at the Icahn School of Medicine at Mount Sinai, will present the late-breaking abstract in a rapid oral presentation titled “Updated clinical results and associated biomarkers from an ongoing phase 1 study of FX-909, a first-in-class peroxisome proliferator-activated receptor gamma (PPARG) inhibitor, in patients (pts) with advanced urothelial carcinoma (adv UC)” today at the 2026 American Society of Clinical Oncology Genitourinary (GU) Cancers Symposium in San Francisco, CA.
“These data offer encouraging signs that FX-909 may help shrink or control tumors in patients with advanced UC, with enriched responses in tumors with a luminal lineage as defined by PPARG overexpression. FX-909 is the first and only agent addressing the underlying transcriptional driver of urothelial cancer,” said Dr. Galsky. “As an oral agent with an acceptable safety and tolerability profile, FX-909 has the potential to offer a much-needed new therapeutic option for patients with advanced UC, and over time, may extend into earlier lines of treatment.”
As of the data cut-off date of November 10, 2025, 46 patients with advanced UC received FX-909 monotherapy across four once-daily dose levels (30 mg, 50 mg, 70 mg and 100 mg), with a median of three prior lines of therapy (range 1-8), including prior enfortumab vedotin and anti-PD(L)1 therapy in 35% of patients. Key highlights from the presented data include:
FX-909 is currently in a Phase 1B expansion study evaluating safety and efficacy in second line or beyond to determine the recommended Phase 2 dose in a biomarker-defined PPARGhigh locally advanced (unresectable) or metastatic UC patient population. The Phase 1 Part B study adopts a randomized 2-stage design. A validated immunohistochemistry (IHC)-based test has been developed to identify patients eligible for enrollment in the expansion study. The company expects interim data in a biomarker-defined population from the randomized portion of the Phase 1B in mid-2026.
More information about the trial is available at clinicaltrials.gov using the identifier NCT05929235.
About Advanced Urothelial Cancer
Advanced urothelial cancer (UC) is an aggressive and challenging form of bladder cancer, representing approximately 25% of all bladder cancers diagnosed each year. In the United States, bladder cancer accounts for approximately 84,000 new cases each year, with urothelial carcinoma being the predominant histologic type. In advanced or metastatic stages, the disease is notably difficult to treat, with over 50% of patients experiencing disease progression within six to nine months of first-line chemotherapy. The five-year survival rate for metastatic UC remains poor, with estimates below 6%. While the introduction of checkpoint inhibitors and targeted therapies has expanded treatment options, clinical outcomes remain suboptimal, underscoring an urgent need for additional and more effective treatment options. Molecular subtyping has revealed that luminal tumors, or tumors that are characterized by high PPARG expression, comprise approximately 65% of advanced urothelial cancers. These luminal tumors are often or invariably characterized by activation of the PPARG (peroxisome proliferator-activated receptor gamma) pathway, which plays a critical role in maintaining tumor identity, promoting tumor growth, and contributing to immune evasion. Novel approaches such as PPARG inhibition are emerging as promising strategies to improve outcomes for patients that have UC with high PPARG expression. It is estimated that the United States alone, there are approximately 14,000 new cases of advanced urothelial cancer with high PPARG expression diagnosed each year, based on the portion of luminal subtypes and overall incidence data.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, a master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
investorrelations@flaretx.com
Media:
Timothy Cockroft
media@flaretx.com
Cambridge, MA, January 9, 2026 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced the appointment of Stephen L. Eck, M.D., Ph.D., as Chief Medical Officer. Dr. Eck brings more than three decades of oncology drug discovery and development leadership across academia, biotechnology and large pharmaceutical companies.
“Throughout my career, I’ve been driven by the goal of bringing better therapies to people living with cancer,” said Dr. Eck. “Flare Therapeutics is advancing a highly differentiated clinical-stage pipeline grounded in novel biology, including FX-909, a novel PPARG inhibitor designed to target the underlying driver of urothelial cancer, and FX-111, which uniquely targets ARON – the transcriptionally activated androgen receptor – to address prostate cancer across all stages of disease. I’m excited to work with the team to thoughtfully and rigorously advance these programs through the clinic.”
In his new role, Dr. Eck will lead Flare Therapeutics’ clinical strategy and development efforts, overseeing clinical trial design and execution and interactions with global health authorities. In connection with this appointment, Michael L. Meyers, M.D., Ph.D. will retire from his role as Chief Medical Officer, effective January 31, 2026.
“Stephen has spent his career turning cutting-edge science into real treatment options for patients and his deep oncology expertise, from target discovery through late-stage development and approval, will be invaluable as we continue to advance and expand our pipeline, led by FX-909 and FX-111. We look forward to his contributions, leadership and engagement with our stakeholders,” said Doug Manion, M.D., FRCP (C), Chief Executive Officer and Board Member of Flare Therapeutics. “I also want to congratulate Michael on his retirement and thank him for his steady leadership and dedication to patients throughout his time at FlareTx. He leaves a strong foundation for our next chapter.”
Stephen Eck, M.D., Ph.D., was most recently Senior Vice President, Clinical Development and Chief Medical Officer at MacroGenics. Previously, Dr. Eck served as Chief Medical Officer of Immatics US, a company focused on TCR-based immunotherapies, and as President and Chief Executive Officer of Aravive Biologics. Prior to these roles, Dr. Eck was Vice President and Global Head of Oncology Medical Sciences at Astellas Pharma, managing a portfolio of assets which included enzalutamide (Xtandi®), erlotinib (Tarceva®) and gilteritinib (Xospata®). Dr. Eck has also held leadership positions in drug development as Vice President of Translational Medicine and Pharmacogenomics at Eli Lilly and as Head of Clinical Oncology at Pfizer. He began his professional career at Monsanto in cancer target discovery and later joined the University of Pennsylvania, where he was the Anne B. Young Assistant Professor of Cancer Research and the Director of the Cancer Gene Therapy Program. Dr. Eck previously served as a director for Circulogene, and on the boards of directors for the Personalized Medicine Coalition and Luminex Corporation. Dr. Eck currently serves on the board of 1cBio and the Central Pennsylvania Clinic. He is a Fellow of the American Association for the Advancement of Science. Dr. Eck holds a B.A. from Kalamazoo College, an M.S. and a Ph.D. from Harvard University, and an M.D. from the University of Mississippi School of Medicine with Internal Medicine Residency and Hematology/Oncology Fellowship training at the University of Michigan.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, Jan. 8, 2026 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced that Doug Manion, M.D., FRCP (C), Chief Executive Officer and Board Member, will present a company overview at the upcoming 44th Annual J.P. Morgan Healthcare Conference on Thursday, January 15, 2026, at 8:00 a.m. PT in San Francisco, CA.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, Nov. 25, 2025 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced that Douglas Manion, M.D., FRCP (C), Chief Executive Officer, will present a company overview at the upcoming Piper Sandler 37th Annual Healthcare Conference on Thursday, December 4, 2025, at 12:10 p.m. ET in New York, NY. Daphne Karydas, President and Chief Financial Officer, will also be available for meetings with investors.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, November 7, 2025 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced the presentation of a correlative biomarker analysis from the Phase 1A clinical study of FX-909, a first-in-class orally available small molecule inhibitor of peroxisome proliferator-activated receptor gamma (PPARG), the master regulator of the luminal lineage, in locally-advanced or metastatic urothelial cancer (UC). This analysis includes novel insights regarding FX-909’s immune modulatory mechanism of action and demonstrate that FX-909 exerts immune-modulatory activity as a single agent, supporting the rationale for combination with an anti-PD-1 inhibitor in advanced UC.
Matthew L. Milowsky, M.D., Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, will present these results in a poster presentation titled “Phase 1 Clinical Data Show FX-909, a First-in-Class Oral PPARG Inhibitor, Drives Immune Modulation and Pro-Inflammatory Cytokine Induction in IO-Experienced Patients with Advanced Urothelial Carcinoma” on Saturday, November 8, 2025 from 10:00 a.m. to 6:35 p.m. ET at the Society for Immunotherapy of Cancer (SITC) 2025 40th Anniversary Annual Meeting in National Harbor, MD.
“Along with the recently presented clinical activity data for FX-909, it is particularly exciting to now present this correlative data showing the induction of pro-inflammatory cytokines and chemokines and the promotion of T-cell expansion. This analysis supports PPARG inhibition as a potential strategy to overcome immune resistance and provides a rationale for the planned cohort evaluating FX-909 in combination with pembrolizumab. I look forward to seeing this cohort initiate early in 2026,” commented Dr. Milowsky.
“Having recently disclosed that FX-909 has achieved clinical proof of concept as a monotherapy, we are very pleased to now share IO-experienced patient level evidence that support our translational hypothesis regarding the immune modulatory mechanism of action of FX-909. We look forward to generating data from our planned cohort of FX-909 in combination with pembrolizumab and believe this approach could provide a “one-two punch” to overcome IO resistance,” said Michaela Bowden, Ph.D., Chief Development Officer of Flare Therapeutics.
Phase 1A Study
Correlative biomarker evaluations were conducted on a subset of IO-experienced advanced UC patients enrolled in the Phase 1A open-label 3+3 dose-escalation study. This analysis evaluated baseline molecular features of archival tumors and longitudinal proteomic and single-cell immune profiles to elucidate the immune-modulatory mechanism of FX-909.
Key highlights include:
Taken together these results demonstrate that FX-909 exerts immune modulatory activity as a single agent supporting the rationale for combination with an anti-PD-1 inhibitor in advanced urothelial carcinoma.
FX-909 Next Steps
FX-909 is currently being evaluated in a Phase 1B expansion study evaluating safety and efficacy in second line or beyond to determine the recommended Phase 2 dose in a biomarker-defined PPARGhigh locally advanced (unresectable) or metastatic UC patient population. The Phase 1 Part B study adopts a randomized 2-stage design. A validated immunohistochemistry (IHC)-based test has been developed to identify patients eligible for enrollment in the expansion study. The company expects interim efficacy data in a biomarker-defined population at the recommended Phase 2 dose in the first quarter of 2026.
In the first quarter of 2026, the company expects to initiate enrollment of a Phase 1 combination cohort that will investigate the safety, tolerability, immunologic effects and preliminary efficacy of escalating doses of FX-909 in combination with standard dose KEYTRUDA® (pembrolizumab) in patients with advanced urothelial carcinoma. As announced on October 21, 2025, Merck (known as MSD outside of the United States and Canada) has agreed to provide its anti-PD-1 therapy KEYTRUDA for this combination cohort under the clinical trial collaboration and supply agreement.
More information about the trial is available at clinicaltrials.gov using the identifier NCT05929235.
About Advanced Urothelial Cancer
Advanced urothelial cancer (UC) is an aggressive and challenging form of bladder cancer, representing approximately 25% of all bladder cancers diagnosed each year. In the United States, bladder cancer accounts for approximately 84,000 new cases each year, with urothelial carcinoma being the predominant histologic type. In advanced or metastatic stages, the disease is notably difficult to treat, with over 50% of patients experiencing disease progression within six to nine months of first-line chemotherapy. The five-year survival rate for metastatic UC remains poor, with estimates below 6%. While the introduction of checkpoint inhibitors and targeted therapies has expanded treatment options, clinical outcomes remain suboptimal, underscoring an urgent need for additional and more effective treatment options. Molecular subtyping has revealed that luminal tumors, or tumors that are characterized by high PPARG expression, comprise approximately 65% of advanced urothelial cancers. These luminal tumors are often or invariably characterized by activation of the PPARG (peroxisome proliferator-activated receptor gamma) pathway, which plays a critical role in maintaining tumor identity, promoting tumor growth, and contributing to immune evasion. Novel approaches such as PPARG inhibition are emerging as promising strategies to improve outcomes for patients that have UC with high PPARG expression. It is estimated that the United States alone, there are approximately 14,000 new cases of advanced urothelial cancer with high PPARG expression diagnosed each year, based on the portion of luminal subtypes and overall incidence data.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, November 3, 2025 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced that company management will present at the following two healthcare conferences in November:
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverage Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, October 30, 2025 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced a poster presentation of the correlative biomarker analysis from the FX-909 Phase 1A clinical study at the upcoming Society for Immunotherapy of Cancer (SITC) 2025 40th Anniversary Annual Meeting being held November 5-9, 2025 in National Harbor, MD.
The presentation at SITC will build on the first disclosure of the part A data from the ongoing Phase 1 study for FX-909, which were recently presented at the AACR-NCI-EORTC International Conference, and include novel insights regarding FX-909’s immune modulatory mechanism of action. FX-909 is a first-in-class orally available small molecule inhibitor of peroxisome proliferator-activated receptor gamma (PPARG), the master regulator of the luminal lineage, currently in a Phase 1B study for the treatment of locally-advanced or metastatic urothelial cancer (UC).
SITC poster presentation details are as follows:
Abstract Title: Phase 1 Clinical Data Show FX-909, a First-in-Class Oral PPARG Inhibitor, Drives Immune Modulation and Pro-Inflammatory Cytokine Induction in IO-Experienced Patients with Advanced Urothelial Carcinoma
Abstract Number: 1318
Session: Exhibits & Poster Viewing
Presenter: Matthew L Milowsky
Date, Time: Saturday, November 8, 2025 from 10:00 a.m. to 6:35 p.m. ET
Location: Lower Level Atrium, Prince George’s ABC
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverages Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
Cambridge, MA, October 24, 2025 — Flare Therapeutics Inc. (FlareTx), a clinical-stage biotechnology company targeting transcription factors to discover precision medicines for oncology and other therapeutic areas, today announced part A data from the ongoing Phase 1 study of FX-909, a first-in-class orally available small molecule inhibitor of peroxisome proliferator-activated receptor gamma (PPARG), the master regulator of the luminal lineage, in locally-advanced or metastatic urothelial cancer (UC). FX-909 demonstrated early signs of clinical benefit in patients with advanced urothelial carcinoma as a monotherapy with a favorable safety profile.
Xin Gao, M.D., Medical Oncologist and Clinical Investigator, Massachusetts General Hospital, presented these results in an oral presentation titled “Safety and clinical activity of FX-909, a first-in-class oral small molecule inhibitor of peroxisome proliferator-activated receptor gamma (PPARG), a master regulator of luminal lineage in patients with advanced urothelial carcinoma” today at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics.
“These preliminary data show a first-in-mechanism drug with promising single agent efficacy at all doses evaluated in a heavily pre-treated locally advanced and metastatic UC patient population. I believe this clinical proof-of-concept supports further development of FX-909. In the ongoing Phase 1B study, patients are being prospectively screened for high expression of PPARG, the hallmark of the luminal lineage, which accounts for approximately 65% of cases of advanced UC. I look forward to seeing the clinical activity data in this biomarker defined population,” commented Dr. Gao.
“In the last decade, the advanced UC treatment landscape has evolved significantly, and the standard of care paradigm has changed. However, despite these advances, there is still a large unmet need for efficacious treatments with better tolerability and durability in this difficult-to-treat patient population. We are encouraged by the preliminary clinical efficacy we are seeing for FX-909 and are focused on executing the ongoing Phase 1B study that will deliver data for our novel PPARG inhibitor in a biomarker-defined population of UC patients. We believe FX-909 may represent a significant step toward addressing the disease at its source by directly targeting the cell of origin and addressing the underlying disease biology, and we are eager to continue exploring the full potential of this agent,” remarked Dr. Michael L. Meyers, Chief Medical Officer at Flare Therapeutics.
Phase 1A Study
The Phase 1A open-label 3+3 dose-escalation study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary clinical activity of FX-909 administered orally once daily (QD) in 28-day cycles and enrolled patients with advanced solid malignancies, including advanced UC. Data for 46 patients, including 36 patients with advanced UC, who were treated across four dose levels; 30 mg (12); 50 mg (15); 70 mg (13); and 100 mg (6) were reported as of September 17, 2025.
Key data highlights include:
Based on the totality of the Part A data, 30 mg and 50 mg QD doses were selected for further optimization. Prospective pre-screening to select for patients with a Tumor Proportional Score (TPS) cutoff of ³60%, newly defined as PPARGhigh, is being implemented in the Phase 1 Part B study.
FX-909 Next Steps
FX-909 is currently being evaluated in a Phase 1B expansion study evaluating safety and efficacy in second line or beyond to determine the recommended Phase 2 dose in a biomarker-defined PPARGhigh locally advanced (unresectable) or metastatic UC patient population. The Phase 1 Part B study adopts a randomized 2-stage design. A validated immunohistochemistry (IHC)-based test has been developed to identify patients eligible for enrollment in the expansion study. The company expects interim efficacy data in a biomarker-defined population at the recommended Phase 2 dose in the first quarter of 2026. More information about the trial is available at clinicaltrials.gov using the identifier NCT05929235.
Webinar Information
An on-demand webinar with company management and investigators, Xin Gao, M.D. and Matthew Galsky, M.D., reviewing this data is now available on the Flare Therapeutics website and can also be accessed here: https://edge.media-server.com/mmc/p/wbj4uhqp. The poster presentation is also available on the Flare Therapeutics website under presentations & publications.
About Advanced Urothelial Cancer
Advanced urothelial cancer (UC) is an aggressive and challenging form of bladder cancer, representing approximately 25% of all bladder cancers diagnosed each year. In the United States, bladder cancer accounts for approximately 84,000 new cases each year, with urothelial carcinoma being the predominant histologic type. In advanced or metastatic stages, the disease is notably difficult to treat, with over 50% of patients experiencing disease progression within six to nine months of first-line chemotherapy. The five-year survival rate for metastatic UC remains poor, with estimates below 6%. While the introduction of checkpoint inhibitors and targeted therapies has expanded treatment options, clinical outcomes remain suboptimal, underscoring an urgent need for additional and more effective treatment options. Molecular subtyping has revealed that luminal tumors, or tumors that are characterized by high PPARG expression, comprise approximately 65% of advanced urothelial cancers. These luminal tumors are often or invariably characterized by activation of the PPARG (peroxisome proliferator-activated receptor gamma) pathway, which plays a critical role in maintaining tumor identity, promoting tumor growth, and contributing to immune evasion. Novel approaches such as PPARG inhibition are emerging as promising strategies to improve outcomes for patients that have UC with high PPARG expression. It is estimated that in the United States alone, there are approximately 14,000 new cases of advanced urothelial cancer with high PPARG expression diagnosed each year, based on the portion of luminal subtypes and overall incidence data.
About Flare Therapeutics Inc.
Flare Therapeutics is a clinical-stage biotechnology company exclusively focused on drugging transcription factors to fully unlock the therapeutic potential of this previously elusive target class. The company’s lead program, FX-909, is a first-in-class orally available small molecule inhibitor of PPARG, the master regulator of the luminal lineage, that is initially being developed for locally advanced or metastatic urothelial cancer. FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy and is actively dosing patients in a Phase 1B to determine the recommended Phase 2 dose in a biomarker-defined population. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, the transcriptionally active, hormone-bound androgen receptor. This approach offers the potential to overcome key vulnerabilities of conventional therapies that target AROFF and has broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC). These two programs, along with an earlier-stage portfolio targeting transcription factors involved in oncology and other therapeutic areas, leverage Flare Therapeutics’ integrated discovery platform of capabilities that identifies novel validated ligands to the undrugged proteome. For more information, please visit www.flaretx.com and follow us on LinkedIn.
Contacts:
Investors:
Sarah McCabe
Media:
Timothy Cockroft
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