IDE849 is an investigational DLL3-targeting antibody-drug conjugate (ADC) carrying a TOP1 inhibitor payload. It is being studied as a potential treatment for cancers that express DLL3, including certain high-grade neuroendocrine carcinomas.

DLL3 is a protein that can be expressed on neuroendocrine cancer cells. Testing for DLL3 expression may help determine whether a patient meets the study's eligibility requirements.

• SCLC patients who have received no more than 3 prior lines of therapy.

• Pulmonary LCNEC who have progressed after any standard treatment.

• Extrapulmonary NECs who have progressed after any standard treatment, including:

  • High-grade gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC)

  • NEC of the prostate (de novo or transformed)

  • Small cell carcinoma or large cell neuroendocrine carcinoma of any other organ

  • Merkel cell carcinoma

  • Transformed SCLC (including any AGA), so long as histology is not mixed

  • Any other NEC with DLL3 2+ by IHC (or high DLL3 expression by local testing, of which they have agreed to accept MDACC’s CLIA assay)

• Any solid tumor with DLL3 2+ by IHC (or high, roughly 50%+ by MDACC local testing)

Note: Future cohorts may or may include additional NEC and DLL3 positive patients, but, at this time, all are being enrolled.

• Must have RECIST v1.1 measurable disease

• Must have acceptable lab values including Hgb >9.0 g/dL, CrCl by Cockroft-Gault >/= 60 mL/min (CrCl 50-59 mL/min will be considered per medical monitor review)

• Mixed histology NSCLC + SCLC excluded (SCLC + LCNEC allowed)

• Untreated symptomatic brain metastases excluded. Previously treated brain metastases or asymptomatic brain metastases not requiring immediate intervention are permitted.

• Chemotherapy washout – 3 weeks; immunotherapy washout – 2 weeks

• Allows prior tarlatamab or other DLL3 T-cell engager

DLL3 expression is an important consideration for this study.

Patients may need tumor testing to determine whether their cancer expresses DLL3 at the required level.

If you have been diagnosed with small cell or large cell neuroendocrine cervical cancer, consider asking your oncologist:

• Has my tumor been tested for DLL3 expression?

• Is additional tissue testing needed?

• Can my existing tumor sample be used?

• Would I meet the study's biomarker requirements?

nectur@mdanderson.org

This information is provided by Lifted Through Hope for educational and informational purposes. It is not medical advice, a treatment recommendation, or a guarantee of eligibility.

Clinical trials have specific inclusion and exclusion criteria, and eligibility must be determined by the study's research team. Trial availability, enrollment status, treatment protocols, and eligibility requirements may change.

Lifted Through Hope does not endorse or recommend any particular clinical trial or treatment. We encourage patients to discuss potential research opportunities with their treating oncologist and the clinical trial team.

Last Information Review: November 5, 2026