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R. Cajal



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    P2.11 - Poster Session 2 - NSCLC Novel Therapies (ID 209)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Medical Oncology
    • Presentations: 1
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      P2.11-044 - Phase IB study to evaluate the efficacy and tolerability of Olaparib (AZD2281) plus Gefitinib in patients (P) with Epidermal Growth Factor Receptor (EGFR) mutation positive advanced Non-Small Cell Lung Cancer (NSCLC) patients (P). (NCT=1513174/GECP-GOAL) (ID 3051)

      09:30 - 09:30  |  Author(s): R. Cajal

      • Abstract

      Background
      Progression-free survival (PFS) and response rate (RR) to EGFR tyrosine kinase inhibitors (TKIs) vary in P with NSCLC driven by EGFR mutations, suggesting that other genetic alterations may influence oncogene addiction. In our experience, high BRCA1 mRNA expression negatively influenced PFS among EGFR mutant P treated with erlotinib. We hypothesiszed that since olaparib can attenuate and/or prevent BRCA1 expression, the addition of olaparib to gefitinib could improve PFS in these P.

      Methods
      This is a Phase IB dose escalation study to identify the maximum tolerated dose (MTD), dose limiting toxicity (DLT), pharmacokinetics (PK), and clinical activity of orally administered olaparib in combination with gefitinib in EGFR mutant advanced NSCLC. In a standard 3+3 design based on toxicity, P were treated with gefitinib 250mg once daily plus olaparib tablets at escalating doses ranging from 100mg BID to 250mg TDS during a 28-day cycle. Steady state Cmax and AUC (AUC0-12) were determined following dosing on Day 7 and 14 of the study and the Day 14:Day 7 treatment ratio calculated to assess the impact on olaparib steady state exposure of dosing in combination with gefitinib

      Results
      22P have been included across four dose levels of olaparib: 100mg BID (3), 200mg BID (6), 200mg TDS (6) and 250mg TDS (7). Median age, 65 (range 39-84); male, 6P; PS 0-1, 20P; EGFR TKI treatment-naïve, 13P; Most toxicities were G1-2, including anemia, leucopenia, nausea, diarrhea, asthenia, rash and anorexia; G3 drug-related events included lymphopenia (1) and anemia (3). No DLT at dose levels 1, 2, and 3; 3 DLT at dose level 4 (G3 anemia and repeated blood transfusion within 4-6 weeks). Few dose reductions or interruptions for both drugs were needed. 1P died due to pulmonary embolism unrelated to study treatment. 19P were evaluated for response: For those not previously treated P, partial responses (PR) were observed in 8P (72,2%), stable disease (SD) in 3P (27,27%) and no progressive disease (PD) (0%). In previously TKI treated P, 3 (37,5%) PR were observed, 3 (37,5%) SD, and 2 (25,5%) PD. Durable PR and SD were observed in both EGFR TKI-naïve and previously treated P.10P are still on treatment. The derived PK parameters were the following: 100mg bid: Olaparib Cmaxss(ug/ml): Day 7:4.60; Day 14:3.53; TR(range) 0.77. AUCss(ug.h/ml) Day 7:24.4; Day 14:18.9; TR:0.79. 200mg bid: Cmaxss(ug/ml): Day 7:7.68; Day 14:6.60; TR:0.89. AUCss(ug.h/ml) Day 7:48.6; Day 14:40.0; TR:0.85; 200mg tds: Cmaxss(ug/ml): Day 7:8.35; Day 14:8.01; TR:0.96. AUCss(ug.h/ml) Day 7: 34.9*; Day 14: 32.7*; TR: 0.94; 250mg tds: Cmaxss(ug/ml): Day 7:9.85; Day 14:9.46; TR:0.97. AUCss(ug.h/ml) Day 7: 44.2*; Day 14: 43.3*; TR: 0.99. *AUC quoted is AUC0-6 not AUCss.

      Conclusion
      This phase IB trial of gefitinib plus olaparib, confirms the tolerability of the combination and the anti-tumor activity seen warrants further exploration in treatment-naïve patients. MTD of olaparib was 200mg TDS. Co-administration of gefitinib does not appear to have altered steady state exposure to olaparib. A phase II randomized trial in treatment-naïve EGFR-mutant advanced NSCLC is planned to start in 2013. The final recommended dose of olaparib will be 200 mg TDS