PT  - JOURNAL ARTICLE
AU  - Dawei Chen
AU  - Hari Menon
AU  - Vivek Verma
AU  - Chunxiao Guo
AU  - Rishab Ramapriyan
AU  - Hampartsoum Barsoumian
AU  - Ahmed Younes
AU  - Yun Hu
AU  - Mark Wasley
AU  - Maria Angelica Cortez
AU  - James Welsh
TI  - Response and outcomes after anti-CTLA4 versus anti-PD1 combined with stereotactic body radiation therapy for metastatic non-small cell lung cancer: retrospective analysis of two single-institution prospective trials
AID  - 10.1136/jitc-2019-000492
DP  - 2020 Jan 01
TA  - Journal for ImmunoTherapy of Cancer
PG  - e000492
VI  - 8
IP  - 1
4099  - http://jitc.bmj.com/content/8/1/e000492.short
4100  - http://jitc.bmj.com/content/8/1/e000492.full
SO  - J Immunother Cancer2020 Jan 01; 8
AB  - Background This study compared response rates and outcomes of combined radiotherapy and immunotherapy (iRT) based on the type of checkpoint inhibitor (anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) vs antiprogrammed death-1 (PD1)) for metastatic non-small cell lung cancer (mNSCLC).Methods We retrospectively reviewed two prospective trials of radiation combined with anti-CTLA4 or anti-PD1 for patients with mNSCLC. Patients undergoing non-salvage stereotactic body radiation therapy (SBRT) to lung sites were selected from both trials and grouped by the immunotherapeutic compound received. Endpoints included in-field and out-of-field response rates, and overall response rate (complete or partial response) (all by response evaluation criteria in solid tumors). Progression-free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method.Results Median follow-up times for the 33 patients (n=17 SBRT+anti-CTLA4, n=16 SBRT+anti-PD1) were 19.6 and 19.9 months. Response rates for out-of-field lesions were similar between anti-PD1 (37%) and anti-CTLA4 (24%) (p=0.054). However, global response rates for all lesions were 24% anti-CTLA4 vs 56% anti-PD1 (p=0.194). The PFS was 76% for anti-CTLA4 vs 94% anti-PD1 at 3 months, 52% vs 87% at 6 months, 31% vs 80% at 12 months, and 23% vs 63% at 18 months (p=0.02). Respective OS values were 76% vs 87% at 6 months, 47% vs 80% at 12 months, and 39% vs 66% at 18 months (p=0.08).Conclusions Both anti-CTLA4 and anti-PD1 agents prompt a similar degree of in-field and out-of-field responses after iRT, although the global response rate and PFS were statistically higher in the anti-PD1 cohort. Further dedicated study and biological mechanistic assessment is required.Trial registration numbers NCT02239900 and NCT02444741.