TellDx-Enabled Circulating Tumor Cell Analysis Predicts Response to DLL3-Targeted Therapy in Small Cell Lung Cancer

-- Study Results Support the use of TellDx to Personalize Cancer Care Management –

-- Clinical study published in Cancer Discovery --

ANDOVER, Mass., Jan. 14, 2026 (GLOBE NEWSWIRE) -- TellBio, Inc., a medical technology company focused on revolutionizing the management of cancer through its unique and proprietary circulating tumor cell (CTC) technology, the TellDx CTC System, announces the publication of data demonstrating that analysis of circulating tumor cells using TellDx can predict patient response to the DLL3-targeting bispecific antibody tarlatamab in small cell lung cancer (SCLC). The paper, “Circulating Tumor Cells Predict Response to the DLL3-targeting Bispecific Antibody Tarlatamab,” was published in Cancer Discovery (DOI 10.1158/2159-8290.CD-25-1483).

“This publication highlights the power of our unique circulating tumor cell analysis to reveal clinically actionable biology that cannot be captured through traditional tissue-based testing. The ability to non-invasively stratify patients and monitor response at the single-cell level has important implications not only for DLL3-targeted therapies, but for the broader management of cancer,” said Annie Partisano, PharmD, MS, Senior Vice President and Head of Operations, TellBio, Inc.

The study, led by investigators at Massachusetts General Hospital (MGH) and Harvard Medical School, shows that quantifying DLL3 expression on circulating tumor cells isolated with TellDx prior to treatment accurately identifies patients most likely to benefit from tarlatamab therapy. Using our unbiased, microfluidic approach to isolate CTCs from blood samples, researchers found that patients with higher fractions of DLL3-positive CTCs experienced significantly improved clinical outcomes, and, importantly, patients with low DLL3 expression rarely responded to treatment.

Small cell lung cancer is an aggressive disease with limited treatment options and unpredictable responses to emerging targeted immunotherapies. Although DLL3 has been thought to be broadly expressed across SCLC tumors, the study reveals substantial heterogeneity at the single-cell level, heterogeneity that is not captured by conventional tissue biopsies.

“The use of an unbiased platform like TellDx to isolate circulating tumor cells in small cell lung cancer was particularly important to the success of the study, since these cancer cells are small in size and do not express classical epithelial markers, which are two features often used to enrich for cancer cells in the blood,” said Daniel A. Haber, MD, PhD, Director of the Massachusetts General Hospital Cancer Center and senior author of the study. “Our finding helps explain the paradox that only half of patients with small cell lung cancer derive major clinical benefit from an antibody-based treatment thought to target all of these cancer cells. In fact, only about half of patients with small cell lung cancer have circulating cancer cells with abundant expression of the targeted marker. This will enable better stratification of patients in future antibody-based therapies.”

The research also demonstrates the value of longitudinal CTC monitoring to assess treatment response and mechanisms of resistance, including loss of target expression or immune dysfunction despite persistent DLL3 positivity. These findings suggest that CTC-based assays may help guide therapeutic decision-making over the course of treatment and inform the development of next-generation strategies in SCLC.

The TellDx CTC iChip platform enables high-efficiency isolation of intact circulating tumor cells without reliance on cell size or epithelial markers. This unbiased approach is particularly well suited for cancers such as SCLC, where conventional enrichment strategies fail to capture key tumor cell populations.

About TellBio

A medical technology Company focused on revolutionizing the detection of cancer metastasis through its unique and proprietary CTC technology, TellDx.

The TellDx CTC System, a fully functional diagnostic solution, isolates live CTCs from patient liquid biopsies. The platform has been optimized following a decade of research and development and has been commercially adopted at multiple cancer centers of excellence. TellDx offers a unique opportunity to isolate CTCs via its microfluidic diagnostic platform to advance translational and clinical efforts and optimize of the care of patients with cancer.

Contacts:

Annie Partisano | apartisano@tellbio.com

For inquiries about deploying TellDx: Contact info@tellbio.com or visit tellbio.com