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A. Frymoyer



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    P3.11 - Poster Session 3 - NSCLC Novel Therapies (ID 211)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Medical Oncology
    • Presentations: 1
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      P3.11-006 - Erlotinib (E) and Dovitinib (TKI258) (D) in Patients (pts) with Metastatic Non-Small Cell Lung Cancer (NSCLC): A Significant Pharmacokinetic (PK) Interaction (ID 878)

      09:30 - 09:30  |  Author(s): A. Frymoyer

      • Abstract

      Background
      Dovitinib (TKI 258) is an oral antiangiogenic agent that targets PDGFR, KIT, FLT3, VEGF, RET, and FGFR. Dovitinib induces CYP1A1/A2, CYP2C19, CYP2C9, and it inhibits CYP3A4. Dovitinib is metabolized mainly by FMO, CYP3A4, and CYP1A1/A2. Erlotinib is metabolized mostly by CYP3A4 (70%) but also by CYP3A5, CYP1A1, and CYP1A2.

      Methods
      This is a phase I 3+3 trial of E+D in patients with EGFR wild-type or mutated metastatic NSCLC who could have previously received E. Four cohorts were planned with E given daily and D given 5 days on/2 days off, starting after a 2-week lead-in of E alone. Only two cohorts enrolled due to dose limiting toxicity (DLT): cohort 1 [150 mg E +300 mg D] and cohort -1 [150 mg E+200 mg D]. Plasma concentrations of E and its metabolite OSI-420 were measured on day 14+/-4 (E alone; pre-dose, 2, 4, 6, 8, and 24 hours) and day 29 +/- 4 (D+E, at same time points). Pharmacokinetic (PK) samples were analyzed by a validated liquid chromatography-tandem mass spectrometry assay. PK parameters for E and OSI-420 were estimated from the plasma concentration data via noncompartmental analysis. Paired-t tests on log transformed PK parameters were used to detect a statistical difference (α < 0.05, 2-sided) between E alone versus E+D treatment days.

      Results
      Nine patients enrolled (3 in cohort 1 and 6 in cohort (-1)). The study was suspended due to excess of DLTs. Best response was evaluable in seven patients. Two unevaluable patients on follow-up scan were on E monotherapy for ~1 month. Four patients discontinued due to grade 3 AEs (syncope (n=1), fatigue (n=1), and pulmonary embolism (n=2)). Three patients had progressive disease and 4 had stable disease (duration: 6 cycles(C), 8 C, and 1-2 C for two patients who stopped due to AE). Two patients required a dose delay in D (one for grade 2 LFT elevation, the other for grade 3 fatigue) and one required dose reduction of E to 100 mg prior to initiation of D (dose-corrected for PK analysis). Six patients had data available for PK analysis. During E alone, erlotinib exposure (average C~max~ 2308 +/- 697 ng/ml and AUC~ 0-24 ~41.0 +/- 15.6 μg*h/ml) was similar to previous reports for multiple daily doses of 150 mg. During D co-administration, the concentrations of E were reduced. C~max~ on average decreased by 83% (p= 0.022) and AUC~0-24 ~by 94% (p= 0.0039). OSI-420 exposure was also reduced during D co-administration.

      Conclusion
      Our small study demonstrates a potential significant PK interaction with decrease of E and its metabolite in the presence of D. This decrease is higher than that reported in combination studies with other CYP1A1 or CYP3A4 inducers. Dovitinib PK data is pending. Given the toxicity and the potential PK interaction, further investigation with this drug combination will be challenging.