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P2.13 - Targeted Therapy (Not CME Accredited Session) (ID 962)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Presentations: 1
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
P2.13-18 - A Multicenter Prospective Biomarker Study to Explore Mechanisms of Afatinib Resistance Based on Digita PCR and Next-Generation Sequencing (ID 12187)
16:45 - 18:00 | Author(s): Takayasu Kurata
Afatinib is an oral irreversible blocker of ErbB-family kinases and shows a pronounced anti-tumor efficacy for advanced non–small cell lung cancer (NSCLC) positive for activating mutations of EGFR. We applied digital polymerase chain reaction (dPCR) and next-generation sequencing (NGS) to explore mechanisms of afatinib resistance.a9ded1e5ce5d75814730bb4caaf49419 Method
Eligible patients had advanced lung adenocarcinoma with EGFR activating mutations. Tumor and plasma samples were collected before afatinib treatment and after treatment failure with disease progression (systemic progressive disease, SPD). DNA from the samples was analyzed by dPCR and NGS.4c3880bb027f159e801041b1021e88e8 Result
Thirty-five patients were enrolled, with a median follow-up time of 15.8 months. Among 25 patients with SPD, tumor, plasma, or both samples were available for 18, 23, and 16 individuals, respectively. dPCR and NGS detected EGFR T790M mutation in 13 (56.5%) and 11 (47.8%) of 23 plasma samples at SPD, with sensitivity and specificity compared with tumor samples being 83.3% and 70.0% (dPCR) and 50.0% and 70.0% (NGS), respectively. Applying the ratio of the number of T790M alleles to that of activating mutations (T/A) for determination of the T790M positivity improved the sensitivity and specificity of plasma analysis compared with tumor analysis to 83.3% and 100% (dPCR) and 57.1% and 100% (NGS), respectively. Among 25 patients with SPD, the T790M mutation of EGFR alone (n = 11), copy number gain (CNG) of NRAS (n = 1), CNG of MET (n = 1), CNG of EGFR plus T790M (n = 1), and CNG and E545K of PIK3CA plus T790M of EGFR (n = 1) were identified by NGS as putative resistance mechanisms against afatinib. No tumor showed transformation to small cell carcinoma. Median progression-free survival was longer in patients with than in those without T790M at SPD (15.1 versus 10.9 months, P =0.25). Median time to SPD was much longer in patients with than in those without T790M at SPD (17.9 versus 10.9 months, P =0.18).8eea62084ca7e541d918e823422bd82e Conclusion
Assessment of T/A ratio with dPCR or NGS improved specificity of plasma analysis for determination of T790M positivity compared with tumor analysis. dPCR and NGS analysis in tumor and plasma samples shed light on exploring mechanisms of afatinib resistance.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): Takayasu Kurata
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