Two biomarker-directed randomized trials in European and Chinese patients with nonsmall-cell lung cancer: the BRCA1-RAP80 Expression Customization (BREC) studies

BACKGROUND

In a Spanish Lung Cancer Group (SLCG) phase II trial, the combination of BRCA1 and receptor-associated protein 80 (RAP80) expression was significantly associated with outcome in Caucasian patients with nonsmall-cell lung cancer (NSCLC). The SLCG therefore undertook an industry-independent collaborative randomized phase III trial comparing nonselected cisplatin-based chemotherapy with therapy customized according to BRCA1/RAP80 expression. An analogous randomized phase II trial was carried out in China under the auspices of the SLCG to evaluate the effect of BRCA1/RAP80 expression in Asian patients.

PATIENTS AND METHODS

Eligibility criteria included stage IIIB-IV NSCLC and sufficient tumor specimen for molecular analysis. Randomization to the control or experimental arm was 1 : 1 in the SLCG trial and 1 : 3 in the Chinese trial. In both trials, patients in the control arm received docetaxel/cisplatin; in the experimental arm, patients with low RAP80 expression received gemcitabine/cisplatin, those with intermediate/high RAP80 expression and low/intermediate BRCA1 expression received docetaxel/cisplatin, and those with intermediate/high RAP80 expression and high BRCA1 expression received docetaxel alone. The primary end point was progression-free survival (PFS).

RESULTS

Two hundred and seventy-nine patients in the SLCG trial and 124 in the Chinese trial were assessable for PFS. PFS in the control and experimental arms in the SLCG trial was 5.49 and 4.38 months, respectively [log rank P = 0.07; hazard ratio (HR) 1.28; P = 0.03]. In the Chinese trial, PFS was 4.74 and 3.78 months, respectively (log rank P = 0.82; HR 0.95; P = 0.82).

CONCLUSION

Accrual was prematurely closed on the SLCG trial due to the absence of clinical benefit in the experimental over the control arm. However, the BREC studies provide proof of concept that an international, nonindustry, biomarker-directed trial is feasible. Thanks to the groundwork laid by these studies, we expect that ongoing further research on alternative biomarkers to elucidate DNA repair mechanisms will help define novel therapeutic approaches.

TRIAL REGISTRATION

NCT00617656/GECP-BREC and ChiCTR-TRC-12001860/BREC-CHINA.

Blood-based CHRNA3 single nucleotide polymorphisms (SNPs) and outcome in advanced non-small cell lung cancer (NSCLC) patients (p)

8033

Background: Nicotonic acetylcholine receptors (nAChRs) are associated with resistance to gemcitabine (gem), cisplatin (cis) and paclitaxel in NSCLC cell lines. Three SNPs of CHRNA3, CHRNA5 and LOC123688 increase lung cancer risk. These SNPs may have influenced outcome in p treated in our phase III trial (Cobo et al. J Clin Oncol 2007;25:2747–54). Methods: Stage IV NSCLC p were treated with customized chemotherapy based on ERCC1 mRNA expression. p in the control arm received docetaxel (doc)/cis; p in the genotypic arm with low ERCC1 levels (low genotypic group [LG]) received doc/cis; p in the genotypic arm with high ERCC1 levels (high genotypic group [HG]) received doc/gem. DNA was extracted from lymphocytes, and CHRNA3 (rs1051730), CHRNA5 (rs16969968) and LOC123688 (rs8034191) SNPs were genotyped with the Taqman allele discrimination assay. Results: A significant interaction was found for CHRNA3 and PS (P = 0.02). In p with PS 0, CT p had a better response than both CC (P = 0.01) and TT (P = 0.02) p, and LG p also had a better response (P = 0.01). When the CHRNA3 genotype was added in the multivariate analysis for progression-free survival (PFS), an improvement was observed in the LG in PS 0 p (P = 0.02). PS 0 p in the LG with the CT genotype attained an 84% response, 12.1-month PFS, and 19-month median survival (MS) ( Table ). Conclusions: CHRNA3 genotyping can improve customized chemotherapy based on tumor ERCC1 mRNA in stage IV NSCLC p with PS 0.

[Table: see text]

No significant financial relationships to disclose.

Phase I trial of vorinostat in combination with erlotinib in advanced non-small cell lung cancer (NSCLC) patients with EGFR mutations after erlotinib progression

e19057

Background: Vorinostat (SAHA) is a histone deacetylase inhibitor that induces differentiation, growth arrest and apoptosis of malignant cells. In vitro, there is a synergistic interaction of vorinostat in combination with gefitinib in NSCLC cell lines. Moreover, vorinostat increases levels of E-cadherin, p21, and downregulates expression of phospho-AKT and phospho-ERK1/2. These molecular findings could reverse resistance to erlotinib in mutant patients. Methods: We conducted a standard 3+3 Phase I trial of oral erlotinib 150 mg QD in combination with oral vorinostat (dose level 1 [DL1], 300 mg QD on days 1–7 every 21 days; DL2, 400 mg QD on days 1–7 every every 21 days, and; DL3, 400 mg QD on days 1–7 and 15–21 in a 28-day cycle). Cycles were repeated for a maximum of 6 cycles until progressive disease (PD) or intolerable toxicity. Pts with advanced NSCLC with EGFR mutations (Exon 19 and 21) after erlotinib progression and ECOG ≤2 were eligible. The main objectives were to determine the maximum tolerated dose (MTD), drug activity and safety of the combination regimen. Results: Thirteen patients have been enrolled up to date, with 9 patients available for this interim analysis (median age, 59 years; range 41–77). One patient (DL3 cohort) experienced a dose limiting toxicity (Grade 3 diarrhoea). The MTD has not been reached. The most common drug-related toxicities of any grade in the first cycle of treatment were anemia (77.8%), skin alterations (66.7%), diarrhoea (66.7%), xerostomy (55.6%), asymptomatic changes in liver function tests (55.6%), and asthenia (55.6%). There were no Grade ≥3 drug-related adverse events during first cycle of treatment and the global analysis of cycles showed asthenia (11.1%), somnolence (11.1%) and hyporexia (11.1%). Four pts discontinued treatment, all due to PD. Of 9 evaluable pts for efficacy, 6 had stable disease as best response (median duration of treatment 6.0 months, range 4–12). Final data will be presented at ASCO meeting. Conclusions: Although accrual continues to determine the MTD, the combination of vorinostat and erlotinib appears to be well tolerated and effective in this group of advanced NSCLC pts with EGFR mutations after erlotinib progression.

No significant financial relationships to disclose.

Characteristics and outcomes of non-small cell lung cancer (NSCLC) patients (pts) carrying epidermal growth factor receptor (EGFR) mutations who progress after initial erlotinib (E) response

8064

Background: Most NSCLC pts with EGFR mutations respond to E; however, resistance to this tyrosine kinase inhibitor (TKI) can be acquired. The resistant T790M mutation has been identified in 50% of progressing pts. We assessed pt characteristics and outcome to additional treatment in 55 EGFR mutated pts after progression to E. Results: Pts mean age was 59±12.5 years; 65% females; 94% never-smokers; 54 adenocarcinoma. 35 pts (63%) were PS ≤2; main metastasis sites were lung (39/71%), bone (21/38%) and liver (10/18%). 22 and 25 pts received E as first- or second-line treatment, respectively. Mutations in tumor were: 65% DelE19 (Δ746–750), 35% L858R mutation; with 31% and 20% serum detection respectively. For the complete cohort, overall response rate (ORR) with E was 78% and time to progression (TTP) was 11.2 months (m) (range, 4–29 m). After progressing to E, 8 pts were re-biopsied, of whom 2 had the T790M mutation; 9 had the T790M mutation in serum (16%). 49% received platinum-based chemotherapy, 14.5% E plus another agent (bevacizumab, fulvestrant, vorinostat), 25.5% single-agent chemotherapy and 11% a non-reversible TKI (HKI-272). ORR for first-line post-E treatments was 33% (CR 1/PR 9) and median TTP was 8 m (range, 4.1–11.8 m). There were no differences in TTP according to gender (p = 0.10), type of mutation (p = 0.63) or severity of skin toxicity (p = 0.16). 11 pts received a second-line post-E treatment with E plus chemotherapy, achieving an ORR of 40%. Median survival was 27 m for all 55 pts (range, 22.9–31.1 m). Conclusions: Pts with EGFR mutations present a biologically different disease which continued to be sensitive to other treatments after progressing to E.

No significant financial relationships to disclose.