Phase 2 cemiplimab PD-1 inhibitor + LITT ablation vs chemo after LITT in rGBM

This randomized Phase 2 study tests whether adding cemiplimab (Regeneron/Sanofi; a PD‑1/CD279–blocking monoclonal antibody that reactivates antitumor T cells) after laser interstitial thermal therapy (LITT; MRI-guided laser ablation of tumor) improves outcomes versus LITT followed by physician’s choice chemotherapy in recurrent, unresectable WHO grade 4 glioblastoma (2nd line+). Patients are randomized 2:1 to LITT + cemiplimab 350 mg IV every 3 weeks (first dose within 14 days after LITT; treatment up to 36 months) or LITT + adjuvant chemotherapy per treating physician (start within 14 days; up to 12 months). Washington University School of Medicine sponsors the trial, leveraging the idea that LITT can cytoreduce tumor and may transiently alter the local tumor microenvironment/blood–brain barrier, potentially making checkpoint blockade more effective than it has been historically in unselected GBM. Today’s care for recurrent GBM is individualized—repeat surgery or LITT when feasible, plus systemic options such as lomustine/temozolomide rechallenge in select patients, bevacizumab for symptom/radiographic control, and clinical trials—so this study asks whether a defined immunotherapy backbone can outperform heterogeneous post-LITT chemotherapy choices.