Circle Pharma Receives FDA Orphan Drug Designation for CID-078 for the Treatment of Small Cell Lung Cancer

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7:05 AM on Monday, June 16

The Associated Press

SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)--Jun 16, 2025--

Circle Pharma, a clinical-stage biopharmaceutical company advancing macrocycle therapeutics for difficult-to-treat cancers, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to CID-078 for the treatment of small cell lung cancer (SCLC).

Small-cell lung cancer is a highly aggressive form of lung cancer that accounts for approximately 13–15% of all lung cancer cases 1 and is strongly linked to tobacco exposure. Despite existing treatments, SCLC has a high recurrence rate and is associated with poor overall prognosis. While improvements in overall survival are occurring with newer therapies, most patients experience rapid disease progression 2.

“The Orphan Drug Designation from the FDA underscores both the seriousness of small cell lung cancer and the lack of effective treatment options,” said Michael C. Cox, PharmD, MHSc, BCOP, SVP, and head of early development Circle Pharma. “We are committed to accelerating the clinical development of CID-078 to offer new hope for patients who face limited therapeutic choices.”

The FDA’s Orphan Drug Designation program is intended to promote the development of drugs for rare diseases or conditions affecting fewer than 200,000 people in the United States 3. This designation provides several development incentives, including seven years of market exclusivity upon regulatory approval, tax credits for qualified clinical trial costs, and eligibility to apply for FDA-administered research grants 4.

Circle Pharma has initiated a Phase 1 clinical trial ( NCT06577987 ) of CID-078 to evaluate its safety, tolerability, pharmacokinetics, and early signs of anti-tumor activity in patients with advanced solid tumors, including SCLC.

About CID-078, Circle Pharma’s Cyclin A/B RxL Inhibitor Program 

CID-078 is an orally bioavailable macrocycle with dual cyclin A and B RxL inhibitory activity that selectively targets tumor cells with oncogenic alterations that cause cell cycle dysregulation. In biochemical and cellular studies, Circle Pharma’s cyclin A/B RxL inhibitors have been shown to potently and selectively disrupt the protein-to-protein interaction between cyclins A and B and their key substrates and modulators, including E2F (a substrate of cyclin A) and Myt1 (a modulator of cyclin B). Preclinical studies have demonstrated the ability of these cyclin A/B RxL inhibitors to cause single-agent tumor regressions in multiple in vivo models. A multi-center phase 1 clinical trial ( NCT06577987 ) is currently enrolling patients.

About Circle Pharma, Inc.

South San Francisco-based Circle Pharma is a clinical-stage biopharmaceutical company harnessing the power of macrocycles to develop 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 for historically undruggable targets. Circle Pharma’s pipeline is focused on targeting cyclins, key regulators of the cell cycle that drive many cancers. Its lead program, CID-078, a cyclin A/B-RxL inhibitor, is in a Phase 1 clinical trial ( NCT06577987 ) for patients with advanced solid tumors.

To learn more about Circle Pharma, please visit www.circlepharma.com.