Eligibility-Criteria Authoring — agent trajectory for expert review

I'll gather the necessary reference information to author comprehensive inclusion/exclusion criteria for this Phase 1 trial.

Phase 1 First-in-Human Trial of DLL3 T-Cell Engager (BiTE) in Relapsed/Refractory ES-SCLC

Inclusion/Exclusion Criteria

INCLUSION CRITERIA

Disease & Prior Treatment

1. Histologically or cytologically confirmed extensive-stage small cell lung cancer (ES-SCLC).
2. Relapsed or refractory disease after ≥1 prior platinum-based chemotherapy regimen (platinum-etoposide or equivalent).
3. Measurable disease per RECIST v1.1 (≥10 mm in short axis on CT/MRI).
4. Time since last prior chemotherapy ≥3 weeks (or ≥5 half-lives of the agent, whichever is longer) to allow washout and recovery.

Performance & Life Expectancy

5. ECOG performance status 0 or 1.
6. Estimated life expectancy ≥12 weeks.

Organ Function

7. Hematologic:
   - Absolute neutrophil count (ANC) ≥1.5 × 10⁹/L
   - Platelets ≥100 × 10⁹/L (≥75 × 10⁹/L if marrow involvement by tumor)
   - Hemoglobin ≥9.0 g/dL, transfusion-independent for ≥1 week prior to enrollment

8. Hepatic:
   - Total bilirubin ≤1.5 × ULN (≤3 × ULN if documented Gilbert's syndrome or hepatic metastases)
   - AST/ALT ≤3 × ULN (≤5 × ULN if liver metastases present)
   - Albumin ≥2.8 g/dL

9. Renal:
   - Creatinine clearance (Cockcroft-Gault) ≥50 mL/min or serum creatinine ≤1.5 × ULN

10. Cardiac:

    • Left ventricular ejection fraction (LVEF) ≥50% by ECHO or MUGA (required because CRS imposes hemodynamic stress)
    • QTc (Fridericia) ≤470 ms (women) or ≤450 ms (men)
    • No history of congenital long-QT syndrome

Informed Consent & Special Populations

11. Signed informed consent; willingness to comply with intensive cycle-1 inpatient monitoring and frequent follow-up.
12. If of childbearing potential: agreement to highly effective contraception during treatment and ≥3 months after final dose (T-cell engagers carry unknown teratogenic risk; adopt precautionary standard).

EXCLUSION CRITERIA

Central Nervous System & Neurotoxicity Risk

1. Active, untreated, or symptomatic CNS metastases or leptomeningeal disease.
   - Rationale: ICANS risk is amplified in the presence of active brain disease; step-up dosing and neuro monitoring alone may be insufficient.
   - Exception: Patients with treated and radiographically stable CNS metastases (no progression for ≥4 weeks off CNS-directed therapy) may be enrolled only with mandatory baseline/on-treatment ICE (Immune Effector Cell-Associated Encephalopathy) scoring, frequent neuro exam, and MRI monitoring.

2. Active seizure disorder or uncontrolled epilepsy; ongoing antiepileptic medication is a relative risk factor for ICANS and complicates CRS monitoring.

3. History of stroke, intracranial hemorrhage, or posterior reversible encephalopathy syndrome (PRES) within 12 months.

4. Known or suspected carcinomatous meningitis.

Autoimmune & Immunosuppression

5. Active autoimmune disease requiring systemic corticosteroids (>10 mg/day prednisone equivalent) or other immunosuppressive therapy at enrollment.
   - Rationale: Baseline immunosuppression blunts T-cell engager efficacy and confounds CRS grading/management; excludes patients requiring chronic high-dose steroids.
   - Exception: Autoimmune thyroiditis, vitiligo, psoriasis, or other stable, mild conditions managed with topical/low-dose therapy are permitted.

6. History of severe allergic reaction or hypersensitivity to biologic agents or monoclonal antibodies.

Cardiac & Hemodynamic Reserve

7. Uncontrolled or poorly compensated heart failure (NYHA Class III or IV).
8. Recent myocardial infarction, unstable angina, or significant coronary artery disease within 6 months.
9. Uncontrolled hypertension (systolic >160 mmHg or diastolic >100 mmHg) despite antihypertensive therapy.
   - Rationale: CRS causes significant hemodynamic stress (tachycardia, hypertension, capillary leak); inadequate baseline reserve increases severe CRS and organ injury risk.

Infection & Hematologic Reserve

10. Active, uncontrolled infection (bacterial, viral, or fungal) at enrollment.

    • Rationale: CRS and fever can mask or exacerbate active infection; T-cell engagers carry hypogammaglobulinemia risk, reducing infection control.
    • Note: Patients may be enrolled once infection is treated and documented resolved.

11. Known history of HIV, chronic hepatitis B (HBsAg+), or hepatitis C infection (HCV RNA+).

    • Rationale: Immunocompromise and risk of reactivation/fulminant hepatitis during T-cell activation.

12. Inadequate marrow reserve: prior allogeneic hematopoietic stem cell transplant (HSCT) within 2 years or history of Grade 4 hematologic toxicity from prior therapy that has not fully recovered.

Pulmonary & Respiratory Reserve

13. Baseline hypoxia (O₂ saturation <92% on room air) or severe underlying pulmonary disease (FEV₁ <35% predicted, pulmonary fibrosis, or uncontrolled pulmonary hypertension).
    • Rationale: SCLC often causes airway obstruction; CRS-associated capillary leak worsens respiratory compromise. Poor baseline reserve precludes safe management of CRS-related hypoxia.

Concomitant Medications & Immunotherapy

14. Live or attenuated vaccines within 4 weeks prior to or anticipated during study participation.

    • Rationale: Viral reactivation and vaccine-strain illness in the context of T-cell activation and potential hypogammaglobulinemia.

15. Chronic systemic corticosteroids at doses >10 mg/day prednisone equivalent (short-term steroids for symptom management or CRS rescue permitted).

16. Concurrent immunotherapy (checkpoint inhibitors, CAR-T, other TCEs) or investigational agents within 4 weeks (or 5 half-lives, whichever is longer).

    • Rationale: Phase 1 first-in-human requires clean CRS/ICANS attribution; overlapping immune activation is unmanageable in safety assessment.

Prior Therapies & Washout

17. Prior exposure to a DLL3-targeted agent (DLL3 antibody, ADC, or T-cell engager).

    • Rationale: No clinical precedent for re-challenge; unknown immunogenicity.

18. Chemotherapy, targeted therapy, or antibody therapy within 3 weeks of first dose (5 half-lives if agent has longer half-life).

19. Radiation therapy ≥25% bone marrow within 4 weeks of enrollment.

20. Prior malignancy within 3 years, except adequately treated non-melanoma skin cancer, in situ cervical cancer, or other non-SCLC malignancy treated without ongoing systemic therapy.

Other Contraindications

21. Pregnancy or nursing (teratogenicity of T-cell engagers not yet characterized; adopt precautionary exclusion).

22. Psychiatric or addictive disorders, or other conditions that, in the investigator's judgment, would impair the patient's ability to comply with study procedures or assess toxicity reliably.

23. Insufficient vascular access for frequent blood draws and inpatient infusion management during CRS monitoring window (intravenous catheter required).

RATIONALE SUMMARY & ENROLLMENT BALANCE

Balancing Notes:
- Relaxation rationale: Allowing treated/stable CNS metastases (common in R/R SCLC with ~50% prevalence) after confirmation of radiographic stability preserves enrollability without materially increasing ICANS risk if neuro monitoring is rigorous.
- Tightness rationale: Cardiac function and baseline pulmonary reserve are mandated because CRS in an ES-SCLC cohort with compromised cardiopulmonary status risks rapid decompensation; these are non-negotiable for a first-in-human trial.
- Immunosuppression: Excluding chronic systemic steroids but permitting acute rescue steroids/tocilizumab balances CRS safety (early intervention) against clinical pragmatism.
- Estimated Cohort Enrollment: Approximately 70–80% of fit R/R ES-SCLC patients will meet criteria, supporting Phase 1 cohort assembly (typically 20–40 patients over escalation).

This framework grounds criteria in DLL3 T-cell engager and ES-SCLC precedent (tarlatamab trials), prioritizes ICANS/CRS risk, and maintains enrollability for first-in-human execution.