Phase I dose escalation and pharmacokinetic evaluation of two different schedules of LY2334737, an oral gemcitabine prodrug, in patients with advanced solid tumors.

BACKGROUND: This Phase-I-study aimed to determine the recommended Phase-II-dosing-schedule of LY2334737, an oral gemcitabine prodrug, in patients with advanced/metastatic solid tumors. Pharmacokinetics, cytokeratin-18 (CK18) levels, genetic polymorphisms, and antitumor activity were additionally evaluated. METHODS: Patients received escalating doses of LY2334737 either every other day for 21 days (d) followed by 7 days-drug-free period (QoD-arm) or once daily for 7 days every other week (QD-arm). The 28 days-cycles were repeated until disease progression or unacceptable toxicity. Standard 3 + 3 dose-escalation was succeeded by a dose-confirmation phase (12 additional patients to be enrolled on the maximum tolerated dose [MTD]). RESULTS: Forty-one patients received QoD- (40-100 mg) and 32 QD-dosing (40-90 mg). On QoD, 3/9 patients experienced dose-limiting toxicities (DLTs) on the 100 mg dose (2 × G3 diarrhea, 1 × G3 transaminase increase); 1 additional DLT (G3 diarrhea) occurred during dose confirmation at 90 mg (12 patients). On QD, 1 patient each experienced DLTs on 60 mg (G3 transaminase increase) and 80 mg (G3 prolonged QTcF-interval); 2/7 patients had 3 DLTs on the 90 mg dose (diarrhea, edema, liver-failure; all G3). The MTD was established at 90 mg for the QoD-arm. Seven patients on QoD and 4 on QD achieved SD (no CR + PR). Pharmacokinetics showed a dose-proportional increase in exposure of LY2334737 and dFdC without accumulation after repeated dosing. Significant increases in CK18 levels were observed. Genetic polymorphism of the cytidine deaminase gene (rs818202) could be associated with ≥ G3 hepatotoxicity. CONCLUSIONS: Both schedules displayed linear pharmacokinetics and acceptable safety profiles. The recommended dose and schedule of LY2334737 for subsequent Phase-II-studies is 90 mg given QoD for 21 day.

Pharmacokinetics and safety of DTS-108, a human oligopeptide bound to SN-38 with an esterase-sensitive cross-linker in patients with advanced malignancies: a Phase I study.

BACKGROUND: DTS-108 is a hydrosoluble prodrug, where the SN-38 moiety is covalently linked to a 20-amino acid vector peptide by a specific esterase-sensitive cross-linker, releasing 7-ethyl-10-hydroxycampthotecin (SN-38) by esterase bond cleavage. METHODS: The pharmacokinetics of DTS-108, adverse events graded according to NCI-CTCv3.1, dose-limiting toxicities at cycle 1, the maximum tolerated dose (MTD), and the recommended Phase II dose (RP2D) of intravenous DTS-108 (1-2 hours) every 2 weeks were evaluated in a first-in-human Phase I study in patients with advanced/metastatic carcinomas, according to an accelerated dose escalation design. SN-38 and SN-38 glucuronide (SN-38G) levels were evaluated with fluorescence high-performance liquid chromatography (HPLC) test, then liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods. RESULTS: Forty-two patients received DTS-108 across 14 dosing cohorts (range 3-416 mg/m2). At 416 mg/m2, three out of six patients had grade 4 neutropenia thereby defining the MTD and the RP2D at 313 mg/m2. Fluorescence HPLC was inaccurate to quantify DTS-108 and its metabolites (SN-38 and SN-38G). New processes and analytical LC/MS/MS methods for testing SN-38 were implemented. At a dose of 313 mg/m2, mean DTS-108, SN-38, and SN-38G area under the plasma concentration-time curve to infinity (coefficients of variation %) were 439,293 (24%), 1,992 (34%), and 4,538 (46%) h·ng/mL. Stable disease (according to Response Evaluation Criteria in Solid Tumors) was observed in nine patients. CONCLUSION: Assessing SN-38 concentration using fluorescence HPLC is questionable since this method failed to monitor dose escalation of DTS-108, a new topoisomerase I inhibitor, due to ex vivo degradation. LC/MS/MS methods were consistent in evaluating SN-38 exposures allowing drug monitoring. The maximum tolerated dose of DTS-108 was 416 mg/m2. The RP2D for intravenous DTS-108 was 313 mg/m2 every 2 weeks in patients with advanced/metastatic solid tumors.