Penfluridol for Relapsed/Refractory Small-Cell Carcinoma of the Lung or Cervix: A Multicenter, Open-Label, Single-Arm Phase Ib/II Trial This study evaluates the safety and anti-tumor activity of oral penfluridol, a first-generation antipsychotic that pre-clinically inhibits small-cell carcinoma (SCC) growth via DRD2 blockade, metabolic reprogramming and apoptosis induction. After ≥2 prior systemic regimens, 33 adult patients (18-75 y) with measurable, metastatic or recurrent lung or cervical SCC will be enrolled across five Chinese centers. A 3+3 dose-escalation (Ib) will establish the recommended Phase II dose (RP2D); an expansion cohort (II) will examine objective response rate (ORR, RECIST 1.1). Secondary end-points include duration of response, progression-free survival, overall survival, safety and exploratory biomarkers. Key inclusion: ECOG 0-1, adequate organ function, no active brain metastases. Penfluridol is administered once weekly, dose-escalated from 20 mg to RP2D, continued until progression or intolerance. Patients receive free study drug, PET imaging and laboratory monitoring.