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P3.01 - Advanced NSCLC (Not CME Accredited Session) (ID 967)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Presentations: 1
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
P3.01-45 - Multifactorial Gene Alterations in EGFR Bypass Pathway are Induced by Afatinib in T790M-Mutant NSCLC Resistant to Osmertinib (ID 13247)
12:00 - 13:30 | Author(s): Takaaki Tokito
The 3rd generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) was developed to target the EGFR T790M resistance mutation in non-small cell lung cancer patients resistant to 1st or 2nd generation EGFR-TKIs. Although some mechanisms of acquired resistance to 3rd generation EGFR-TKI such as EGFR C797S mutation have been reported, the effect and resistant mechanisms to afatinib followed by osmertinib has not been well-known.a9ded1e5ce5d75814730bb4caaf49419 Method
Nine patients with EGFR T790M-mutant NSCLC resistance to 3rd generation EGFR-TKI were enrolled in this study and treated with afatinib. Plasma samples were collected before treatment, 4 weeks after treatment, and at disease progression. Mutation profile and tumor mutation burden (TMB) in plasma cell free DNA (cfDNA) were analyzed by CAPP-seq.4c3880bb027f159e801041b1021e88e8 Result
The objective response rate and median progression-free survival of afatinib were 0% and 2.0 months, respectively. At the time of 4 weeks after treatment, four patients developed disease progression and five patients showed stable disease. A total of 36 somatic mutations or amplification were detected in plasma cfDNA before afatinib treatment; EGFR activating mutations in 8 patients, T790M mutation in 4, TP53 mutations in 6, PIK3CA mutations in 3, BRAF mutations in 3, MET amplification in 3, CTNNB1 mutations in 2, ERBB2 mutations in 2, C797S mutation in 1, SMAD4 mutation in 1, EGFR minor mutation in 1, KRAS mutation in 1, and APC mutation in one patient. EGFR C797S mutation in cfDNA was detected during afatinib treatment in two cases. In the patients having stable disease at 4 weeks after treatment, mutant allele frequency and TMB tended to decline once, and then increased in association with disease progression.8eea62084ca7e541d918e823422bd82e Conclusion
Detection of mutant allele frequency and TMB of ctDNA by CAPP-seq could monitor the effectiveness and resistance to afatinib. Resistant mechanisms to afatinib might be characterized by multifactorial bypass pathway activation.6f8b794f3246b0c1e1780bb4d4d5dc53
PL02 - Presidential Symposium - Top 5 Abstracts (ID 850)
- Event: WCLC 2018
- Type: Plenary Session
- Track: Advanced NSCLC
- Presentations: 1
- Coordinates: 9/25/2018, 08:15 - 09:45, Plenary Hall
PL02.01 - Overall Survival with Durvalumab Versus Placebo After Chemoradiotherapy in Stage III NSCLC: Updated Results from PACIFIC (ID 14701)
08:15 - 08:25 | Author(s): Takaaki Tokito
In the global, Phase 3 PACIFIC study (Antonia 2017; NCT02125461), durvalumab significantly improved progression-free survival (PFS) versus placebo in Stage III, unresectable NSCLC patients without progression after chemoradiotherapy (CRT) (stratified HR, 0.52; 95% CI, 0.42–0.65; P<0.001). This was the first major advance in this disease setting for many years. Here we report the second primary endpoint overall survival (OS) for PACIFIC.
Patients with WHO PS 0/1 (any PD-L1 tumor status) who received ≥2 cycles of platinum-based CRT were randomized (2:1) 1–42 days post-CRT to durvalumab 10 mg/kg IV Q2W or placebo up to 12 months, stratified by age, sex, and smoking history. Primary endpoints were PFS from randomization (blinded independent central review; RECIST v1.1) and OS (interim analysis reported). Secondary endpoints included time to death or distant metastasis (TTDM) and PFS2 (time to second progression) from randomization and safety. Time to first/second subsequent therapy or death (TFST/TSST) were supportive assessments for PFS/PFS2.
Between May 2014 and April 2016, 713 patients were randomized of whom 709 received treatment (durvalumab, n=473; placebo, n=236). As of March 22, 2018 (data cutoff), median follow-up duration was 25.2 months (range, 0.2–43.1). After discontinuation, 41.0% and 54.0% in the durvalumab and placebo groups received subsequent anticancer therapy; overall, 8.0% and 22.4% received additional immunotherapy. Durvalumab significantly improved OS versus placebo (stratified HR 0.68, 99.73% CI, 0.469–0.997; P=0.00251), with the median not reached (NR; 95% CI, 34.7 months–NR) and 28.7 months (95% CI, 22.9–NR), respectively. Durvalumab improved OS in all pre-specified subgroups. Updated PFS remained similar (stratified HR 0.51, 95% CI, 0.41–0.63), with medians of 17.2 and 5.6 months with durvalumab and placebo, respectively. Durvalumab improved the updated TTDM (stratified HR 0.53, 95% CI, 0.41–0.68), as well as PFS2 (stratified HR 0.58, 95% CI, 0.46–0.73), TFST (stratified HR 0.58, 95% CI, 0.47–0.72) and TSST (stratified HR 0.63, 95% CI, 0.50–0.79). Within the durvalumab and placebo groups, 30.5% and 26.1% had grade 3/4 any-causality AEs, 15.4% and 9.8% discontinued due to AEs, and no new safety signals were identified.
Durvalumab demonstrated statistically significant and clinically meaningful improvement in OS compared with placebo, supported by secondary endpoints such as PFS2. PACIFIC is the first study to show a survival advantage following CRT in this population, providing compelling evidence for the unprecedented benefit of durvalumab treatment as the standard of care.a9ded1e5ce5d75814730bb4caaf49419
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