P3.02c-031 Immune Checkpoint Inhibitors (IC) and Paradoxical Progressive Disease (PPD) in a Subset of Non-Small Cell Lung Cancer (NSCLC) Patients: Topic: IT

In non-squamous NSCLC PD-L1 negative patients (pts), IC might increase the risk of early death compared to docetaxel in the phase III study Checkmate 057. Tumor Growth Rate (TGR) is calculated using 2 CTscans and the time interval between the 2 exams. It integrates tumor dynamics and kinetics. We hypothesized that TGR could identify a subset of pts named PPD, in which IC could accelerate tumor progression, leading to early death. We performed a retrospective case study of all NSCLC pts treated by IC in a single institution between Dec. 12 and Feb. 16. CT scan were centrally reviewed by a senior radiologist and assessed according to RECIST 1.1 criteria. We calculated TGR at baseline of IC (baseline CTscan (n) vs n-1 CTscan) and TGR during IC (n+2 CTscan vs n+1 CTscan). We further estimated the difference (deltaTGR) between TGR during IC and TGR at baseline. DeltaTGR>0 means IC speeds up tumor growth. PPD was defined as deltaTGR>50%, corresponding to an absolute increase in TGR greater than 50% per month. PDL1 expression was assessed with the SP142 clone. 89 pts were eligible. 58% were male, median age 60 (41-78); 15% never smokers. 62 pts had adenocarcinoma, 21 squamous and 6 other histologies. Mutational status was unknown for 14 pts; 36% wild type, 9 pts EGFRmut, 25 pts KRASmut. PDL1 expression was positive in 25 pts, unknown in 57 pts. 52 pts (58%) received nivolumab, 25 pembrolizumab and 12 atezolizumab. Treatement was received as 1-3rd line in 52 pts, and as ≥ 4th line in 37 pts. Overall, 25 pts (28%) had a response according to RECIST 1.1 criteria, 31 (35%) a stable disease. Median OS was 14.7 months. During IC, deltaTGR was <0 in 79 pts and >0 in 20 pts. Among the 20 pts with deltaTGR>0, 9 had a PPD. Characteristics (age, sex, smoking status, pathology, number of previous line, PDL1 status) of the 9 pts were not different from other pts. None of the PPD were pseudoprogression. Median OS of PPD vs others was 3.2 and 23 months, respectively. PPD was not more frequent in tumors with high baseline TGR. Our results suggest that PPD is a new subset of response criteria in which IC may increase tumor progression, leading to a poorer survival. Rapidly growing disease at study entry nor RECIST criteria could predict the occurrence of PPD.