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O15 - NSCLC - Chemotherapy II (ID 109)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Medical Oncology
- Presentations: 1
- Moderators:G. Richardson, J.V. Heymach
- Coordinates: 10/29/2013, 10:30 - 12:00, Bayside Auditorium A, Level 1
O15.02 - The Spanish Lung Cancer Group (SLCG) BRCA1-RAP80 Expression Customization (BREC) randomized phase III trial of customized chemotherapy in advanced non-small-cell lung cancer (NSCLC) patients with wild-type epidermal growth factor receptor (EGFR) (NCT00617656/GECP-BREC) (ID 1157)
10:30 - 12:00 | Author(s): I. Chaib
RAP80, a component of the BRCA1 complex, influenced outcome both in p with low BRCA1 expression treated with cisplatin (cis)/gemcitabine (gem) and in p with intermediate/high BRCA1 levels treated with cis/docetaxel (doc) or with doc alone in the SLCG phase II customized chemotherapy trial (NCT00883480). Based on these findings, the SLCG and the French Lung Cancer Group performed a prospective, randomized phase III trial in metastatic NSCLC patients to compare non-customized cis/doc with customized therapy customized according to BRCA1 and RAP80 mRNA expression levels.
From 2008 to 2013, patients with wild-type EGFR were randomized 1:1 to the control or experimental arm. Planned accrual was 391 patients. Treatment in the control arm was cis/doc, while patients in the experimental arm received treatment according to their BRCA1 and RAP80 levels: 1) those with low RAP80, regardless of BRCA1 levels, received cis/gem; 2) those with intermediate/high RAP80 and low/intermediate BRCA1 received cis/doc; and 3) those with intermediate/high RAP80 and high BRCA1 received doc alone. The primary endpoint was progression-free survival (PFS).
At 15 October 2012, 279 patients had been included and the planned interim analysis was performed. PFS was 5.49 months (m) in the control and 4.38 m in the experimental arm (P=0.07). Overall survival (OS) was 12.66 m in the control and 8.52 m in the experimental arm (P=0.006). Response rate (RR) was 37.3% in the control and 27% in the experimental arm (P=0.07). In the multivariate analysis including PS, treatment arm, BRCA1, RAP80, histology, smoking status and metastatic site, only extrathoracic metastases were associated with an increased risk of progression (HR, 1.78; P=0.02). In a post hoc analysis restricted to patients with ECOG PS 0, PFS was 3.91 m in the control and 7.47 m in the experimental arm (P=0.01) for those with low RAP80 levels (experimental group 1). PFS for patients in experimental groups 1, 2 and 3 was 7.47, 7.01 and 3.22 m, respectively (P=0.02). OS for patients in experimental groups 1, 2 and 3 was 28.88, 15.86 and 11.81 m, respectively (P=0.04).
Based on the negative results for PFS at the interim analysis, accrual was closed on this study. The negative results may be due to the poor predictive capacity of RAP80 and/or to the inclusion of doc alone as a treatment in the experimental arm. In addition, doc/cis may not have been the ideal combination for the control arm. Customized chemotherapy could be further encouraged in oncogene-driven pan-negative patients with PS 0.
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P3.01 - Poster Session 3 - Cancer Biology (ID 147)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P3.01-015 - <b>Outcome in pemetrexed/cisplatin-treated non-small-cell lung cancer (NSCLC) patients according to mRNA expression levels of BRCA1, TS, AEG1 and REV3 </b> (ID 1170)
09:30 - 16:30 | Author(s): I. Chaib
REV3, the catalytic subunit of the translesion synthesis (TLS) polymerase x, can continue replication past DNA adducts. Depletion of REV3 sensitizes A549 lung cancer cells to cisplatin. REV3 expression is part of a gene signature that predicted pemetrexed sensitivity in 17 NSCLC cell lines. BRCA1, TS, AEG1 and RAP80 are involved in DNA damage repair through homologous recombination. The homologous recombination and TLS pathways have non-redundant functions in response to cisplatin. We hypothesized that low mRNA expression of these genes – either alone or in combination – could confer improved outcome to cisplatin/pemetrexed in NSCLC patients.
REV3, BRCA1, RAP80, TS and AEG1 mRNA expression was examined by quantitative RT-PCR and categorized by terciles. Expression of each gene was correlated with outcome in 47 cisplatin/pemetrexed-treated NSCLC patients.
63.8% male; 47% smokers; 80.9% ECOG PS 1; 80.8% adenocarcinoma. Overall response rate was 51%, with no differences according to expression levels of any of the genes. Progression-free survival (PFS) for patients with low, intermediate and high BRCA1 levels was 13.4, 5.5 and 3.9 months (m), respectively (P=0.005). Similar differences in PFS were observed according to TS (P=0.003) and AEG1 (P<0.001) expression. The hazard ratio (HR) for PFS for patients with high BRCA1 levels was 4 (P=0.002). Overall survival (OS) for patients with low, intermediate and high BRCA1 levels was 29.7, 7.4 and 6.3 m, respectively (P=0.05). Similar differences in OS were observed according to TS (P=0.005) and AEG1 (P=0.001) expression. HR for OS for patients with high BRCA1 levels was 3.6 (P=0.004). There were no differences in PFS or OS according to REV3 or RAP80 levels. However, the joint effect of BRCA1 and REV3 was significant for predictive modeling. PFS for patients with low, intermediate and high levels of both genes was 14.9, 7.2 and 2.8 m, respectively (P=0.001). OS for patients with low, intermediate and high levels of both genes was 29.7, 7.8 and 6.3 m, respectively (P=0.04).
Low BRCA1 expression predicts longer PFS and OS in pemetrexed/cisplatin-treated NSCLC p. Low TS and AEG1 levels have similar predictive value. The combination of low BRCA1 and REV3 expression confers longer PFS and OS. Analysis of these genes could be useful for customizing pemetrexed/platinum chemotherapy.