Radiotherapy to augment pembrolizumab responses and outcomes in metastatic non-small cell lung cancer: Pooled analysis of two randomized trials.
Abstract Number : 9548
Abstract : Poster Session
Indication : Non-Small Cell Lung Cancer
Intervention: Pembrolizumab alone versus pembrolizumab combined with radiation therapy (RT).
Companies : Merck Sharp & Dohme
Technology : Monoclonal antibody
In all, 131 patients were analyzed (n = 66 pembrolizumab; n = 65 pembrolizumab/RT (iRT)). ORR was 21% in the pembrolizumab arm vs. 38% in the iRT arm (p =0.01); DCR was 53% in the pembrolizumab arm vs. 67% in the iRT arm (p = 0.0009); PFS was 4.4 m vs 8.3 m (p = 0.046); and OS was 9.2 m vs 19.2 m (HR 0.66; p = 0.040). Ablative RT (24Gy/3 fractions and 50Gy/4 fractions) had better ORRs of 48% and 54%, respectively, compared to 18% for nonablative RT (45Gy/15 fractions) and 20% for pembrolizumab alone (p , 0.05, respectively).
The addition of RT to immunotherapy significantly increased the ORR of unirradiated lesions and was additionally associated with significant improvements in PFS and OS. Ablative RT was associated with response rates significantly higher than those of non-ablative RT, possibly due to a detrimental effect of non-ablative RT on ALC. These hypothesis-generating findings require dedicated, large-volume, and randomized studies for corroboration.
The addition of RT to immunotherapy significantly increased the ORR.