Maintenance treatment with [225Ac]Ac-DOTATATE plus tislelizumab for extensive‑stage small cell lung cancer with somatostatin receptor–positive tumors

A Phase I Study to Evaluate the Safety and Preliminary Efficacy of [225Ac]Ac-DOTATATE Injection Combined With Tislelizumab in the Maintenance Treatment Period for Patients of Extensive-stage Small Cell Lung Cancer (ES-SCLC) With Somatostatin Receptors (SSTR)+ as First-line Treatment

This trial will try to see if adding a targeted radioligand ([225Ac]Ac‑DOTATATE) to the immunotherapy drug tislelizumab as maintenance helps people with extensive‑stage small cell lung cancer whose tumors are somatostatin receptor positive after first‑line treatment.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 24 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: Peking University Cancer Hospital & Institute (Academic / other)
• Drugs / interventions: chemotherapy, immunotherapy, tislelizumab
• Locations: 1 site (Beijing, Beijing Municipality)
• Trial ID: NCT07413042 on ClinicalTrials.gov

What this trial studies

This is a phase I, single‑center, open‑label study enrolling patients with extensive‑stage small cell lung cancer who have completed induction first‑line therapy and whose tumors are SSTR‑PET positive. Participants will receive [225Ac]Ac‑DOTATATE in combination with tislelizumab during the maintenance period, with close monitoring for safety and tolerability. The trial requires at least one measurable lesion per RECIST 1.1 and ECOG 0–1, and collects laboratory, adverse event, and tumor response data to identify preliminary signs of efficacy. Primary focus is on dose‑related and treatment‑related toxicities, with secondary observation of tumor control measures.

Who should consider this trial

Good fit: Ideal candidates are adults (18–80) with extensive‑stage SCLC confirmed by pathology who completed standard first‑line induction, are SSTR‑PET positive, have ECOG 0–1, at least one measurable lesion, and adequate organ and bone marrow function.

Not a fit: Patients whose tumors are SSTR‑PET negative, who have poor performance status (ECOG ≥2), significant organ dysfunction, or who have not completed first‑line induction are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, the combination could help keep disease under control longer during the maintenance period and delay relapse.

How similar studies have performed: Targeting somatostatin receptors with radioligands has shown benefit in certain neuroendocrine tumors, but use of an alpha‑emitter like [225Ac]Ac‑DOTATATE and its combination with PD‑1 blockade in SCLC is largely experimental with limited prior human data.

Eligibility criteria

Inclusion Criteria:

1. Patients must have the ability to understand and sign an approved informed consent form (ICF).
2. Patients must be \>= 18 and \<＝80 years of age.
3. Extensive-stage small cell lung cancer that requires histopathological or cytological confirmation.
4. Presence of at least 1 measurable site of disease (based on RECIST 1.1).
5. ECOG score of 0 or 1.
6. SSTR-PET positive.
7. Sufficient bone marrow capacity and organ function:

   Serum creatinine ≤1.5×ULN or creatinine clearance ≥50 ml/min (Cockcroft Gault formula).

   Hemoglobin≥90g/L, neutrophil count ≥1.5×10\^9/L, platelets≥100×10\^9/L. Serum total bilirubin ≤1.5×ULN. Serum albumin ≥30g/L. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≤ 2.5×ULN，or ALT/AST≤5×ULN with liver metastases.

   Partially activated prothrombin time (APTT) ≤1.5 x ULN.
8. Subjects of childbearing potential voluntarily use an effective method of contraception, such as condoms, oral or injectable contraceptives, IUDs, etc., during treatment and within 6 months of the last use of the trial drug.

Exclusion Criteria:

1. Pregnant or lactating females.
2. Received systemic antitumor therapy such as targeted therapy, immunotherapy, antitumor herbal therapy, chemotherapy within 4 weeks prior to initiation of study treatment.
3. Uncontrolled congestive heart failure.
4. uncontrolled diabetes mellitus, including baseline fasting glucose \> 2 x ULN.
5. Known hypersensitivity to Lutetium\[177Lu\] Oxodotreotide Injection or \[225Ac\]Ac-DOTATATE Injection and their excipients.
6. Other treatment options (e.g., chemotherapy, targeted therapy) that, in the opinion of the investigator, are more appropriate for the patient than the treatment provided in the study based on the patient's disease characteristics.
7. Unsuitable for the study for any reason, in the opinion of the investigator.

Where this trial is running

Beijing, Beijing Municipality

• Peking University Cancer Hospital & Institute — Beijing, Beijing Municipality, China (Recruiting)

Study contacts

• Study coordinator: Zhi Yang

Conditions SCLC, Extensive Stage