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MINI 27 - Biology and Other Issues in SCLC (ID 152)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Small Cell Lung Cancer
- Presentations: 1
MINI27.08 - NOTCH3 Protein Expression and Outcome in Small Cell Lung Cancer (SCLC) and Therapeutic Targeting with Tarextumab (Anti-Notch 2/3) (ID 2999)
16:45 - 18:15 | Author(s): A. Spira
NOTCH expression is associated with cancer cell survival via effects on cancer stem/progenitor cells. Targeting NOTCH2 and 3 decreases growth and survival of SCLC patient-derived human tumor xenografts (PDX). Phase1b/2 trials testing Tarextumab (TRXT) anti-NOTCH2/3 therapy are underway (NCT01647828 and NCT01859741) and show promising anti-tumor activity. Here, we studied NOTCH3 protein expression using immunohistochemistry (IHC) in SCLC human tissues and correlated with survival. Also, we studied NOTCH3 gene expression in phase 1b patients (pts) treated with TRXT.
For NOTCH IHC staining, murine monoclonal antibodies were generated by immunizing mice with a NOTCH3 extracellular domain (ECD) protein, then creating hybridomas. Clones were screened by FACS and western blots for specificity to NOTCH3.ECD. A lead clone was selected for NOTCH3 protein measurement in 47 SCLC samples represented in a tissue microarray from Yale Pathology Tissue Services (YPTS). NOTCH3 signal was determined in tumors using H-scores generated by Leica Aperio Scanscope IHC membrane image analysis. For survival analysis, NOTCH3 signal was binarized with cutoffs defined by X-tile software. For the phase 1b clinical trial, a standard 3+3 dose escalation design was employed with cohorts of 3 to 6 pts treated at each dose level. TRXT was given IV on Day 1 of each 21 day cycle with etoposide 100 mg/m (Days 1-3) and cisplatin 80 mg/m[2 ]or carboplatin at AUC 5 (Day 1) for 6 cycles, followed by TRXT alone every 21 days until progression of disease or unacceptable toxicities. Then, the MTD TRXT plus etoposide and carboplatin was confirmed in a cohort of 6 subjects. All pts are required to submit tissues for Notch 3 gene expression and IHC staining.
A single hybridoma clone demonstrating specific reproducible membranous staining with a dynamic range for NOTCH3.ECD in control and PDX tissues was chosen for IHC analysis in SCLC human FFPE tissues (n=47). Forty cases (85.1%) demonstrated NOTCH3 signal, with eighteen (38.3%) having none to very low signal. Of the 31 cases with adequate follow-up, there was a strong trend with worse outcome and high NOTCH3 expression in the extensive stage (p=0.063), but not in limited stage (p=0.857). The level of significance was a function of the experimental cut-point and can only be considered exploratory. Finally, 27 pts were treated with TRXT in the phase 1b trial, with an overall response rate of 84%. The median duration of treatment was 128 days (6 cycles) with mPFS and mOS of 124 and 228 days, respectively. The median follow-up for PFS and OS was 86 and 107 days, respectively. Twenty-five pts have tissues evaluable for NOTCH3 gene expression and the analysis is underway.
NOTCH3 IHC staining showed expression in most SCLC cases, with high NOTCH3 trending towards worse survival in extensive stage. This supports the rationale of targeting NOTCH3 by TXRT in SCLC pts. Further evaluation of the prognostic and predictive value of TRXT for anti-Notch therapies in SCLC is underway in an ongoing Phase 2 clinical trial.
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P1.01 - Poster Session/ Treatment of Advanced Diseases – NSCLC (ID 206)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Advanced Diseases - NSCLC
- Presentations: 1
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
P1.01-076 - TIGER-1: A Phase 2/3 Study of First Line Rociletinib or Erlotinib in EGFR-Mutant NSCLC (ID 944)
09:30 - 17:00 | Author(s): A. Spira
Activating EGFR mutations including the L858R mutation and exon 19 deletions (del19) are key drivers of non-small cell lung cancer (NSCLC) in 10%–15% of patients of European and 30%–35% of Asian descent. Acquired resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs) such as erlotinib can be driven by additional EGFR mutations, with exon 20 T790M accounting for 50%–60% of cases. Rociletinib (CO-1686) was designed to inhibit T790M as well as L858R and del19 while sparing wild-type EGFR and has demonstrated response rates up to 67% in patients with T790M mutations who had progressed on first or later line EGFR inhibitor therapy. Rociletinib continues to be well tolerated by patients in ongoing studies. Given that T790M mutated subclones commonly emerge during treatment with existing EGFR inhibitors, early targeting of T790M along with initial activating mutations is a rational approach to delay progression.
TIGER-1 (NCT02186301) is a randomized, open label study of rociletinib vs erlotinib in patients with mutant EGFR NSCLC. Patients with histologically or cytologically confirmed metastatic or unresectable locally advanced treatment-naive NSCLC (no prior therapy in the metastatic setting and no CNS disease), with documentation of ≥1 activating EGFR mutation (excluding exon 20 insertions) and biopsy within 60 days will be enrolled in this 2-part study. All patients will be randomized 1:1 to rociletinib (500 mg twice daily) or erlotinib (150 mg once daily) and treated until death, qualifying adverse events or disease progression. Patients will be stratified by sensitizing EGFR mutation (T790M, del19, L858R, or other) and territory (Asian vs non-Asian geography). The same patient eligibility criteria will be used for the Phase 2 and Phase 3 portions of TIGER-1. The phase 2 portion is currently enrolling and will transition to the Phase 3 portion upon enrollment of the 201[st] patient. The maturing Phase 2 dataset will contribute to decision-making rules for the Phase 3 interim analyses. The Phase 3 portion will incorporate larger cohorts; the final sample sizes will be determined by interim analyses where the chances of success will be estimated at pre-planned enrollment milestones. The primary endpoint is PFS; secondary efficacy endpoints include objective response rate, duration of response, disease control rate and overall survival. Safety will be assessed via standard adverse event reporting. PFS and OS will be summarized with Kaplan-Meier plots. The stratified log-rank and hazard ratio will compare PFS distributions for rociletinib- vs erlotinib-treated patients. Enrollment is ongoing. 1. Herbst R et al. N Engl J Med. 2008 2. Yu H et al. Clin Cancer Res. 2013 3. Sequist LV J Clin Oncol. 2014