Response-Adapted PULSAR Radiotherapy

Fractionated stereotactic radiosurgery (SRS, 5 doses total) for brain metastasis given in two "pulses" (3 fractions + 2 fractions) with second pulse adapted to interim radiographic response Adaptive Changes Allowed: Omission of 2nd "pulse" in >=25% responders or tumor target size/shape change in remainder

Radiographic response-adapted thoracic tumor radiotherapy given as single doses ('pulses') before standard of care chemoimmunotherapy cycles. Adaptive Changes Allowed: Tumor target (size/shape), # of doses (reduction) Adaptive Changes Allowed: Tumor target (size/shape), # of doses (reduction)

Cohort-Specific Rationale COHORT A (ES-SCLC Personalized ultrahypofractionated stereotactic ablative radiotherapy (PULSAR) Thoracic Tumor): Chemoimmunotherapy with 4-6 cycles of platinum/etoposide and PD-L1 (Programmed Death-Ligand 1 protein) inhibition has become the standard systemic therapy for extensive stage small cell lung cancer (ES-SCLC), based on modest but significant OS (overall survival) benefits seen with the addition of either atezolizumab or durvalumab to chemotherapy in the IMpower133 and CASPIAN trials, respectively.

To characterize feasibility, safety, and/or preliminary efficacy of personalized strategies to adapt standard radiotherapy treatments to individual patient responses.

Live record on ClinicalTrials.gov →

• Performance status ECOG 0-2
• Extensive stage small cell lung cancer diagnosed by tissue biopsy within 180 days of registration.
• Patient must be planned for or receiving standard of care chemoimmunotherapy.
• Patient must have received no more than 3 cycles by time of study enrollment.
• Able and indicated according to investigator to receive thoracic radiotherapy
• Diagnosis of solid tumor malignancy with MRI-defined brain metastasis lesions within 60 days of registration

Inclusion criteria as written on the registry, trimmed. The full list, with exclusions, is on the live record.