PURPOSE Neoadjuvant chemotherapy plus nivolumab has been shown to be effective in resectable non–small-cell lung cancer (NSCLC) in the NADIM trial (ClinicalTrials.gov identifier: NCT03081689 ). The 3-year overall survival (OS) and circulating tumor DNA (ctDNA) analysis have not been reported. METHODS This was an open-label, multicenter, single-arm, phase II trial in which patients with stage IIIA NSCLC, who were deemed to be surgically resectable, were treated with neoadjuvant paclitaxel (200 mg/m2 once a day) and carboplatin (area under curve 6) plus nivolumab (360 mg) once on day 1 of each 21-day cycle, for three cycles, followed by adjuvant nivolumab monotherapy for 1 year (240 mg once every 2 weeks for 4 months, followed by 480 mg once every 4 weeks for 8 months). The 3-year OS and ctDNA analysis were secondary objectives of the trial. RESULTS OS at 36 months was 81.9% (95% CI, 66.8 to 90.6) in the intention-to-treat population, rising to 91.0% (95% CI, 74.2 to 97.0) in the per-protocol population. Neither tumor mutation burden nor programmed cell death ligand-1 staining was predictive of survival. Conversely, low pretreatment levels of ctDNA were significantly associated with improved progression-free survival and OS (hazard ratio [HR]: 0.20; 95% CI, 0.06 to 0.63, and HR: 0.07; 95% CI, 0.01 to 0.39, respectively). Clinical responses according to RECIST v1.1 criteria did not predict survival outcomes. However, undetectable ctDNA levels after neoadjuvant treatment were significantly associated with progression-free survival and OS (HR: 0.26; 95% CI, 0.07 to 0.93, and HR: 0.04; 95% CI, 0.00 to 0.55, respectively). The C-index to predict OS for ctDNA levels after neoadjuvant treatment (0.82) was superior to that of RECIST criteria (0.72). CONCLUSION The efficacy of neoadjuvant chemotherapy plus nivolumab in resectable NSCLC is supported by 3-year OS. ctDNA levels were significantly associated with OS and outperformed radiologic assessments in the prediction of survival.

This study represents the real word experience with nivolumab and the results are consistent with previously reported in clinical trials. PS 2 and the presence of CNS metastases are associated with poor prognosis.

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8509 Background: Patients with stage IIIA (N2 or T4N0) are potentially curable but median overall survival is only around 15 months and complete pathologic response with conventional chemotherapy (CT) is no more than 9%. Methods: A Phase II, single-arm, open-label multicenter study of resectable stage IIIA N2-NSCLC adult patients with CT plus IO as a neoadjuvant treatment: three cycles of Nivolumab (NV) 360mg IV Q3W + paclitaxel 200mg/m2 + carboplatin AUC 6 IV Q3W followed by adjuvant NV treatment for 1 year. After complete neoadjuvant therapy, tumor assessment is performed prior to surgery. Surgery is performed in the 3rd or 4th week after day 21 of the third cycle of neoadjuvant treatment. The study aims to recruit 46 pts. The primary endpoint is Progression-Free Survival (PFS) at 24 months. Efficacy is explored using objective pathologic response criteria. We present final data on all patients included in this study that underwent surgical assessment. Results: At the time of submission, 46 pts had been included and 41 had undergone surgery. CT-IO was well-tolerated and surgery was not delayed in any patient. None of the pts withdrew from the study preoperatively due to progression or toxicity. 41 surgeries had been performed and all tumors were deemed resectable, with R0 resection in all cases. 34 pts (83%) achieved major pathologic response (MPR) (CI 95% 71-95%), and 24 (71%) of them had a complete pathologic response (CPR) (CI 95% 54-87%). Downstaging was seen in 90% (CI 95% 81-100%) of cases. By RECIST, 29 pts (71%) (CI 95% 56-85%) had partial response and 3 (7%) (CI 95% 0-16%) complete response. Conclusions: This is the first multicentric study to CT-IO in the neoadjuvant setting in stage IIIA. Neoadjuvant CT-IO with nivolumab in resectable IIIA NSCLC yields a high complete pathologic response rate that has never been seen previously and unsuspected by RECIST criteria. Preliminary correlative analyses in blood samples are included in a separate abstract. EudraCT Number: 2016-003732-20. Clinical trial information: NCT 03081689.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the digestive tract, and this disease has served as a paradigmatic model for successful rational development of targeted therapies. The introduction of tyrosine kinase inhibitors with activity against KIT/PDGFRA in both localized and advanced stages has remarkably improved the survival in a disease formerly deemed resistant to all systemic therapies. The Spanish Society of Medical Oncology (SEOM) guidelines provide a multidisciplinary and updated consensus for the diagnosis and treatment of GIST patients. We strongly encourage that the managing of these patients should be performed within multidisciplinary teams in reference centers.

With a higher overall response rate and lower toxicity, GD is a good first treatment option for advanced NSCLC.

9076 Background: PD-L1 has emerged as a potential biomarker for predicting responses to immunotherapy and as a prognostic factor in non-small cell lung cancer (NSCLC). In this network meta-analysis, we aimed to evaluate the efficacy of first-line PD-(L)1 monotherapy in advanced NSCLC patients with high PD-L1 expression. Methods: We conducted a systematic search in PubMed to identify all eligible trials from inception until 1 November 2020, with no start date limit applied. Only phase III trials evaluating the efficacy of first-line (1L) PD-(L)1 monotherapy in patients with stage IIIB/stage IV NSCLC and high PD-L1 expression were included. Results: Six clinical trials (KEYNOTE-024, KEYNOTE-042, EMPOWER Lung-01, IMpower110, MYSTIC and CheckMate-026) with 2,111 patients were included. In head-to-head comparisons, immunotherapy showed a significant improvement in progression-free survival (PFS: HRpooled = 0.69, 95% CI: 0.52-0.90, p = 0.007), overall survival (OS: HRpooled = 0.69, 95% CI: 0.61-0.78; p < 0.001) and overall response rate (ORR) (Risk ratio [RR]pooled = 1.354, 95% CI: 1.04-1.762, p = 0.024) compared to chemotherapy (CT). In the assessment of relative efficacy for PFS through indirect comparisons, pembrolizumab (results from KEYNOTE-024) ranked highest followed by cemiplimab and atezolizumab, with statistical significance determined across some of the drugs. In terms of OS, cemiplimab ranked highest followed by atezolizumab and pembrolizumab, although non-significant OS was determined across these drugs. Overall, 1L PD-(L)1 monotherapy improved OS in almost all subgroups, reaching statistical significance in men (HRpooled = 0.624, 95% CI: 0.51-0.72, p < 0.001), non-Asian patients (HRpooled = 0.66, 95% CI: 0.55-0.79, p < 0.001), all patients regardless of age ( < 65 years [HRpooled = 0.72, 95% CI: 0.57-0.90, p = 0.005]; ≥65 years [HRpooled = 0.61, 95% CI: 0.48-0.77, p < 0.001]), ECOG PS status (ECOG PS = 0 [HRpooled = 0.68, 95% CI: 0.56-0.82, p < 0.001; ECOG PS = 1 [HRpooled = 0.59, 95% CI: 0.43-0.82, p = 0.001) and histological tumour type (Squamous [HRpooled = 0.49, 95% CI: 0.37-0.67, p < 0.001; Non-squamous [HRpooled = 0.67, 95% CI: 0.52-0.87, p = 0.003). In the case of smokers and NSCLC stage, only current/former smokers (HRpooled = 0.623, 95% CI: 0.47-0.83, p = 0.001) and patients with stage IV disease* (HRpooled = 0.687, 95% CI: 0.59-0.81, p < 0.001) benefited from single PD-(L)1 monotherapy over CT. Conclusions: PD-(L)1 inhibitor monotherapy improves efficacy outcomes in the 1L setting of advanced NSCLC patients with high PD-L1 expression. Current/former smokers ≥65 years, with ECOG PS = 1 and squamous NSCLC benefited most from this therapy. *KEYNOTE-042 was the only study including patients with stage IIIB NSCLC.

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