Research describes progress of discovery-stage macrocycles to orally bioavailable compounds targeting E2F-high and G1-S checkpoint-compromised cancers
SOUTH SAN FRANCISCO, CA, March 12, 2026 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced publication of research in the Journal of Medicinal Chemistry titled, “Orally Bioavailable Cyclin A/B RxL Inhibitors: Optimization of a Novel Class of Macrocyclic Peptides That Target E2F-High and G1-S-Checkpoint-Compromised Cancers.” The paper is included in the journal’s special issue on Peptide Therapeutics.
The publication builds on the company’s August 2025 Journal of Medicinal Chemistry paper titled, “Discovery of Cell-Permeable Macrocyclic Cyclin A/B RxL Inhibitors that Demonstrate Antitumor Activity,” which described the first cell-permeable macrocyclic cyclin A/B RxL inhibitors and provided initial in vivo proof-of-concept efficacy.
“This publication demonstrates the capability of our MXMO™ macrocycle platform to bring forward orally bioavailable macrocycles against therapeutic targets that have been refractory to small molecule chemistry,” said James Aggen, Ph.D., vice president of medicinal chemistry at Circle Pharma. “Our earlier work established that the cyclin A/B hydrophobic patch was druggable with macrocycles. This new research demonstrates these molecules can be delivered orally with compelling in vivo activity.”
Cyclins A and B regulate cell cycle progression by recruiting substrates through an RxL-mediated interaction. In cancers characterized by RB1 loss or elevated E2F activity – including nearly all small-cell lung cancers – this pathway becomes dysregulated, driving uncontrolled tumor growth. Rather than inhibiting CDK catalytic activity, Circle Pharma’s approach disrupts the protein-protein interactions between cyclins A and B and their RxL-containing substrates, selectively killing E2F-high tumor cells.
CID-078, Circle Pharma’s oral cyclin A/B RxL inhibitor is currently being evaluated in a multi-center Phase 1 clinical trial in patients with advanced solid tumors (NCT06577987).
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Matt Clawson
1AB
SOUTH SAN FRANCISCO, CA, February 17, 2026 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced management will participate in upcoming investor conferences in February and March, as follows:
Oppenheimer 36th Annual Healthcare Life Sciences Conference
Presentation Date/Time: 3:20 p.m. ET, Wednesday, Feb. 25, 2026
Participants: David J. Earp, J.D., Ph.D., president and chief executive officer; Anne Borgman, M.D., chief medical officer; Rob Lauzen, chief financial officer
Location: Virtual
TD Cowen 46th Annual Health Care Conference
Date: Monday, March 2, 2026
Participants: David J. Earp, J.D., Ph.D., president and chief executive officer; Anne Borgman, M.D., chief medical officer; Rob Lauzen, chief financial officer
Location: Boston
Leerink Global Healthcare Conference
Date: Wednesday, March 11, 2026
Participants: David J. Earp, J.D., Ph.D., president and chief executive officer; Rob Lauzen, chief financial officer
Location: Miami
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler, 1AB
Investors:
Rob Lauzen, Circle Pharma
Robert.Lauzen@circlepharma.com
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SOUTH SAN FRANCISCO, CA, January 5, 2026 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced that David J. Earp, J.D., Ph.D., president and chief executive officer, will present at the 44th Annual J.P. Morgan Healthcare Conference on Wednesday, January 14, 2026 at 5:00 p.m. PT.
Dr. Earp will provide an overview of the company’s pipeline, including CID-078, a first-in-class oral macrocyclic cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors, and CID-165, a first-in-class oral macrocyclic cyclin D1 RxL inhibitor, with potential applications in malignancies, including ER-positive breast cancer and lymphomas.
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Steve Klass
1AB
SOUTH SAN FRANCISCO, CA, December 17, 2025 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced the nomination of CID-165, a first-in-class, orally bioavailable macrocyclic cyclin D1 RxL inhibitor, as the development candidate for its second oncology program.
Cyclin D1 is a regulatory protein that plays a crucial role in cell cycle progression and is overexpressed or translocated in malignancies, including ER-positive breast cancer and lymphomas. In these cancers, cyclin D1 drives cell proliferation by binding to the tumor suppressor retinoblastoma protein (Rb) leading to uncontrolled cell division. In preclinical studies, CID-165 has been shown to potently and selectively disrupt the cyclin D1-Rb interaction allowing Rb to remain active and suppress cancer cell proliferation. CID-165 demonstrates robust anti-tumor activity in cyclin D1-driven preclinical cancer models including in combination with other therapies such as CDK4/6-dual inhibitors, CDK4-selective inhibitors, and endocrine therapies.
“Cyclin D1 has long been recognized as a key oncogenic driver across many solid tumors and hematologic malignancies, yet it has remained an elusive direct therapeutic target,” said Marie Evangelista, Ph.D., senior vice president and head of cancer biology at Circle Pharma. “Our MXMO™ platform has allowed us to design a novel macrocyclic molecule, CID-165, with the precision and selectivity needed to directly block cyclin D1-Rb signaling while minimizing effects on related cyclins, such as cyclin D3, an approach aimed at reducing side effects commonly observed with dual CDK4/6 inhibitors.”
“Despite the transformative impact of CDK4/6 inhibitors for the treatment of ER-positive breast cancer, many patients eventually experience disease progression or adverse events that impact their quality of life,” said Anne Borgman, M.D., chief medical officer of Circle Pharma. “CID-165 is designed to address these limitations through selective inhibition of cyclin D1, a central driver of tumor proliferation, while avoiding adverse events associated with broader CDK4/6 blockade. We look forward to advancing CID-165 toward IND submission in late 2026 and potentially translating the compelling preclinical activity into benefit for patients.”
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Steve Klass
1AB
SOUTH SAN FRANCISCO, CA, December 1, 2025 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced the appointment of Anne E. Borgman, M.D., as chief medical officer. Dr. Borgman is an accomplished chief medical officer, business executive, scientific advisor and board director with more than 20 years of experience devising and executing clinical development strategies that have led to multiple oncology drug approvals.
“Dr. Borgman joins Circle with an established track record of leading clinical development teams to successful oncology drug approvals in both the U.S. and EU. Her ability to translate strong science into meaningful therapies for patients is exceptional,” said David J. Earp, J.D., Ph.D., president and chief executive officer of Circle Pharma. “Her leadership and deep experience will be instrumental as we continue the clinical development of our first-in-class cyclin A/B RxL inhibitor, CID-078, advance our cyclin D1 into the clinic, and prepare for the next stages of growth at Circle.”
“Circle Pharma’s MXMO™ platform is opening the door to a promising new class of targeted macrocycle therapies, with the potential to address some of the most challenging and impactful cancer targets such as the cyclins,” said Dr. Borgman. “I’m thrilled to join this talented team and to help guide the clinical development of programs that could make a real difference for patients with few treatment options.”
Prior to joining Circle, Dr. Borgman served as chief medical officer of Sutro Biopharma, where she advanced the company’s lead asset into pivotal trials in ovarian cancer and infant leukemia. Before that, Dr. Borgman served as vice president and therapeutic area lead, oncology, hematology, and transplant, at Jazz Pharmaceuticals, where she was responsible for global drug development for four marketed products (Defitelio®, VYXEOS ®, ZEPZELCA® and RYLAZE®), and drug development plans for several emerging targets. Previously, Dr. Borgman was vice president, clinical research & development at Exelixis, where she helped lead the global development for cabozantinib and oversaw the development and execution of multiple Phase 3 clinical trials. She has also held leadership positions in oncology drug development at KaloBios Pharmaceuticals, Talon Therapeutics (formerly Hana Biosciences), and Abbott Laboratories, where she created the early development strategies for venetoclax and veliparib while serving as global project head.
Dr. Borgman currently serves on the board of directors of clinical-stage oncology companies NextCure, Curis, and NiKang. Dr. Borgman received an M.D. from Loyola University Chicago Stritch School of Medicine and completed a residency in pediatrics at Baylor College of Medicine and a fellowship in pediatric hematology-oncology and bone marrow transplantation from the David Geffen School of Medicine at UCLA. She received her B.S. in biochemistry from University of Illinois.
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Steve Klass
1AB
SOUTH SAN FRANCISCO, CA, November 4, 2025 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced management will participate in upcoming investor conferences in November:
LifeSci Growth & Innovation Summit
November 17, 2025
Participants: David J. Earp, J.D., Ph.D., president and chief executive officer; Rob Lauzen, chief financial officer
Location: London, UK
Jefferies Global Healthcare Conference – London
November 18-20, 2025
Participants: David J. Earp, J.D., Ph.D., president and chief executive officer; Rob Lauzen, chief financial officer
Location: London, UK
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer and other serious illnesses. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Steve Klass
1AB
SOUTH SAN FRANCISCO, CA, November 3, 2025 – Circle Pharma, Inc., a clinical-stage biopharmaceutical company pioneering next-generation targeted macrocycle therapeutics for cancer, today announced the appointment of Rob Lauzen as chief financial officer. Mr. Lauzen brings deep financial expertise and broad experience within the life sciences industry, having most recently served as chief financial officer of Prilenia Therapeutics, where he oversaw all aspects of the company’s capital strategy, finance, and investor relations functions.
“We are thrilled to welcome Rob to the Circle Pharma leadership team,” said David J. Earp, J.D., Ph.D., president and chief executive officer of Circle Pharma. “This is an exciting time for Circle as we advance our lead program, CID-078, through Phase 1 clinical development and continue to expand our pipeline of first-in-class oral macrocycle therapeutics that target cyclins — key drivers of cancer that have long been considered undruggable. Rob’s proven expertise in corporate finance, capital markets, and strategic planning will be instrumental as we build on our strong momentum and position the company for long-term growth.”
Prior to serving as chief financial officer of Prilenia Therapeutics, Mr. Lauzen was vice president, investor relations and head of financial planning & analysis at Dyne Therapeutics. Earlier, Mr. Lauzen held roles in the healthcare investment banking group at Morgan Stanley, where he advised clients on a broad range of strategic and financing needs, executing over $185 billion in M&A transactions and over $10 billion of equity offerings. Mr. Lauzen holds a B.A. in engineering sciences from Dartmouth College.
“I’m excited to join Circle Pharma at such a pivotal stage in its evolution,” said Mr. Lauzen. “With a strong scientific foundation and a clear focus on cyclins that are implicated in large populations of cancer patients, Circle is well positioned to deliver transformative new therapies. I look forward to supporting the team’s mission to translate this groundbreaking science into meaningful benefits for patients and value for our stakeholders.”
About Circle Pharma
Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop next-generation targeted therapies for cancer and other serious illnesses. The company’s proprietary MXMO™ platform overcomes key challenges in macrocycle drug development, enabling the creation of intrinsically cell-permeable and orally bioavailable therapies, including for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. The company’s lead program, CID-078, is a cyclin A/B RxL inhibitor in Phase 1 clinical development for patients with advanced solid tumors. Circle Pharma is based in South San Francisco, CA. For additional information, please visit us at circlepharma.com and follow us on LinkedIn and X.
Contacts:
Media:
Josie Butler
1AB
Investors:
Steve Klass
1AB