Abstract 1355P
Background
Immune checkpoint inhibitors (ICIs) represent a cornerstone for treatment of advanced non-small cell lung cancer (NSCLC) patients. Discussion is ongoing about the best criteria for radiological assessment, as novel patterns of response have been described (eg. hyperprogression, pseudoprogression). Our paper aims to evaluate Tumor Growth Rate (TGR) as a tool to identify pts who are benefitting from ICI despite progressive disease (PD) at first CT.
Methods
Tumor real volume (TV) was calculated with a dedicated CT software (Philips IntelliSpace Portal v. 8.0, Philips Medical System, Nederland). Target lesions were identified according to RECIST 1.1 criteria. For each patient we had 3 measurement of TV. The CT performed immediately before ICI start was TC0; TC-1 was performed 8-12 weeks before, while TC+1 was the first assessment after ICI start. We calculated TGR1 and TGR2, that are respectively the percentage increase in TV before and during treatment. Finally, we compared TGR1 and TGR2 of each patient. If there was no Progressive Disease (PD), we called them DC (Disease Control). If disease progressed but TGR2 was lower than TGR1, we called them LvPD (Lower velocity PD) and if TGR2 was higher than TGR1, HvPD (Higher velocity PD).
Results
We retrospectively reviewed clinical records of 58 pretreated NSCLC patients who received ICI and a control group of 33 patients treated with standard 2nd line chemotherapy (Cht). In ICI group, 17 were considered HvPD, 21 LvPD and 20 DC. Median OS was 4.4 months (95% CI 2.0 - 6.8, reference) for HvPD, 7.1 months (95% CI 5.4 – 8.8) for LvPD, HR 0.43 (95% CI 0.21 - 0.87), p 0.018, and 20.9 months (95% CI 12.5 – 29.3) for DC group, HR 0.17 (95% CI 0.07 - 0.39), p < 0.001. The difference between LvPD and DC group was also significant, HR 2.55 (95% CI 1.13 – 5.74), p 0.024. The frequency of treatment beyond progression were similar between groups (p 0.333). No difference in OS was detected in control group (p 0.786).
Conclusions
Decrease of tumor growth velocity, even in the presence of radiological PD, may result in a clinical benefit in patients treated with ICI but not with Cht. Taking into consideration pre-treatment TGR could help physician in deciding to continue ICIs beyond PD or not.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
C. Caramella: Financial Interests, Institutional, Advisory Board: AstraZeneca, BMS, MSD, Roche. B. Besse: Financial Interests, Institutional, Research Grant: AbbVie, Amgen, AstraZeneca, Biogen, Blueprint Medicines, BMS, Celgene, Eli Lilly, GSK, Ignyta, Ipsen, Merck, MSD, Nektar, Onxeo, Pfizer, PharmaMar, Sanofi, Spectrum Pharmaceuticals, Takeda and Tiziana Pharm 4D Pharma, AbbVie, Amgen, Aptitude Health, Astr. A. Ardizzoni: Financial Interests, Institutional, Advisory Board: MSD, AstraZeneca, Novartis, Roche, and Bristol Myers Squibb. All other authors have declared no conflicts of interest.