Midostaurin administration in two hemodialysis patients.

Midostaurin is a multitargeted tyrosine kinase inhibitor approved by the Food and Drug Administration for FMS-related tyrosine kinase 3-positive acute myeloid leukemia in combination with standard daunorubicin and cytarabine induction and high-dose cytarabine consolidation. The pharmacokinetics of midostaurin in the setting of severe renal impairment (creatinine clearance [CrCl] 15-29 mL/min utilizing Cockcroft-Gault method) and end-stage renal disease are unknown. Midostaurin is primarily metabolized by the liver through the CYP3A4 enzyme with fecal excretion accounting for 95% of the dose (4% recovered as unchanged drug). Only 5% of the parent drug is found in the urine. This is the first case report documenting the administration of midostaurin in two patients with end-stage renal disease on HD. Given the limited excretion of both active and inactive metabolites of midostaurin in the urine, one does not expect an increase in toxicity related to impaired drug excretion. Although this report describes the likely successful utilization of midostaurin, caution should be exercised when administering in patient populations with end organ disease. Medical history, concomitant comorbidities, and goals of therapy should be taken into account.

Simultaneous Physiologically Based Pharmacokinetic (PBPK) Modeling of Parent and Active Metabolites to Investigate Complex CYP3A4 Drug-Drug Interaction Potential: A Case Example of Midostaurin.

Midostaurin (PKC412) is being investigated for the treatment of acute myeloid leukemia (AML) and advanced systemic mastocytosis (advSM). It is extensively metabolized by CYP3A4 to form two major active metabolites, CGP52421 and CGP62221. In vitro and clinical drug-drug interaction (DDI) studies indicated that midostaurin and its metabolites are substrates, reversible and time-dependent inhibitors, and inducers of CYP3A4. A simultaneous pharmacokinetic model of parent and active metabolites was initially developed by incorporating data from in vitro, preclinical, and clinical pharmacokinetic studies in healthy volunteers and in patients with AML or advSM. The model reasonably predicted changes in midostaurin exposure after single-dose administration with ketoconazole (a 5.8-fold predicted versus 6.1-fold observed increase) and rifampicin (90% predicted versus 94% observed reduction) as well as changes in midazolam exposure (1.0 predicted versus 1.2 observed ratio) after daily dosing of midostaurin for 4 days. The qualified model was then applied to predict the DDI effect with other CYP3A4 inhibitors or inducers and the DDI potential with midazolam under steady-state conditions. The simulated midazolam area under the curve ratio of 0.54 and an accompanying observed 1.9-fold increase in the CYP3A4 activity of biomarker 4ß-hydroxycholesterol indicated a weak-to-moderate CYP3A4 induction by midostaurin and its metabolites at steady state in patients with advSM. In conclusion, a simultaneous parent-and-active-metabolite modeling approach allowed predictions under steady-state conditions that were not possible to achieve in healthy subjects. Furthermore, endogenous biomarker data enabled evaluation of the net effect of midostaurin and its metabolites on CYP3A4 activity at steady state and increased confidence in DDI predictions.

Midostaurin, a Novel Protein Kinase Inhibitor for the Treatment of Acute Myelogenous Leukemia: Insights from Human Absorption, Metabolism, and Excretion Studies of a BDDCS II Drug.

The absorption, metabolism, and excretion of midostaurin, a potent class III tyrosine protein kinase inhibitor for acute myelogenous leukemia, were evaluated in healthy subjects. A microemulsion formulation was chosen to optimize absorption. After a 50-mg [14C]midostaurin dose, oral absorption was high (>90%) and relatively rapid. In plasma, the major circulating components were midostaurin (22%), CGP52421 (32.7%), and CGP62221 (27.7%). Long plasma half-lives were observed for midostaurin (20.3 hours), CGP52421 (495 hours), and CGP62221 (33.4 hours). Through careful mass-balance study design, the recovery achieved was good (81.6%), despite the long radioactivity half-lives. Most of the radioactive dose was recovered in feces (77.6%) mainly as metabolites, because only 3.43% was unchanged, suggesting mainly hepatic metabolism. Renal elimination was minor (4%). Midostaurin metabolism pathways involved hydroxylation, O-demethylation, amide hydrolysis, and N-demethylation. High plasma CGP52421 and CGP62221 exposures in humans, along with relatively potent cell-based IC50 for FMS-like tyrosine kinase 3-internal tandem duplications inhibition, suggested that the antileukemic activity in AML patients may also be maintained by the metabolites. Very high plasma protein binding (>99%) required equilibrium gel filtration to identify differences between humans and animals. Because midostaurin, CGP52421, and CGP62221 are metabolized mainly by CYP3A4 and are inhibitors/inducers for CYP3A, potential drug-drug interactions with mainly CYP3A4 modulators/CYP3A substrates could be expected. Given its low aqueous solubility, high oral absorption and extensive metabolism (>90%), midostaurin is a Biopharmaceutics Classification System/Biopharmaceutics Drug Disposition Classification System (BDDCS) class II drug in human, consistent with rat BDDCS in vivo data showing high absorption (>90%) and extensive metabolism (>90%).

Comparison of two endogenous biomarkers of CYP3A4 activity in a drug-drug interaction study between midostaurin and rifampicin.

PURPOSE: Midostaurin, a multitargeted tyrosine kinase inhibitor, is primarily metabolized by CYP3A4. This midostaurin drug-drug interaction study assessed the dynamic response and clinical usefulness of urinary 6ß-hydroxycortisol to cortisol ratio (6ßCR) and plasma 4ß-hydroxycholesterol (4ßHC) for monitoring CYP3A4 activity in the presence or absence of rifampicin, a strong CYP3A4 inducer. METHODS: Forty healthy adults were randomized into groups for either placebo or treatment with rifampicin 600 mg QD for 14 days. All participants received midostaurin 50 mg on day 9. Midostaurin plasma pharmacokinetic parameters were assessed. Urinary 6ßCR and plasma 4ßHC levels were measured on days 1, 9, 11, and 15. RESULTS: Both markers remained stable over time in the control group and increased significantly in the rifampicin group. In the rifampicin group, the median increases (vs day 1) on days 9, 11, and 15 were 4.1-, 5.2-, and 4.7-fold, respectively, for 6ßCR and 3.4-, 4.1-, and 4.7-fold, respectively, for 4ßHC. Inter- and intrasubject variabilities in the control group were 45.6 % and 30.5 %, respectively, for 6ßCR, and 33.8 % and 7.5 %, respectively, for 4ßHC. Baseline midostaurin area under the concentration-time curve (AUC) correlated with 4ßHC levels (ρ = -0.72; P = .003), but not with 6ßCR (ρ = 0.0925; P = .6981). CONCLUSIONS: Both 6ßCR and 4ßHC levels showed a good dynamic response range upon strong CYP3A4 induction with rifampicin. Because of lower inter- and intrasubject variability, 4ßHC appeared more reliable and better predictive of CYP3A4 activity compared with 6ßCR. The data from our study further support the clinical utility of these biomarkers.

Effect of midostaurin on the pharmacokinetics of P-gp, BCRP, and CYP2D6 substrates: assessing potential drug-drug interactions in healthy participants : Brief title: Drug-drug interaction of midostaurin.

PURPOSE: Midostaurin, approved for FLT3-mutated acute myeloid leukemia and advanced systemic mastocytosis, is mainly metabolized by cytochrome P450 (CYP) 3A4. Midostaurin exhibited potential inhibitory effects on P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic anion-transporting polyprotein 1B1, and CYP2D6 in in vitro studies. This study investigated the pharmacokinetic (PK) effects of midostaurin on P-gp (digoxin), BCRP (rosuvastatin) and CYP2D6 (dextromethorphan) substrates in healthy adults. METHODS: This was an open-label, single-sequence, phase I clinical study evaluating the effect of single-dose midostaurin (100 mg) on the PK of digoxin and rosuvastatin (Arm 1), and dextromethorphan (Arm 2). Participants were followed up for safety 30 days after last dose. In addition, the effect of midostaurin on the PK of dextromethorphan metabolite (dextrorphan) was assessed in participants with functional CYP2D6 genes in Arm 2. RESULTS: The effect of midostaurin on digoxin was minor and resulted in total exposure (AUC) and peak plasma concentration (Cmax) that were only 20% higher. The effect on rosuvastatin was mild and led to an increase in AUCs of approximately 37-48% and of 100% in Cmax. There was no increase in the primary PK parameters (AUCs and Cmax) of dextromethorphan in the presence of midostaurin. The study treatments were very well tolerated with no occurance of severe adverse events (AEs), AEs of grade ≥ 2, or deaths. CONCLUSION: Midostaurin showed only a minor inhibitory effect on P-gp, a mild inhibitory effect on BCRP, and no inhibitory effect on CYP2D6. Study treatments were well tolerated in healthy adults.

Midostaurin drug interaction profile: a comprehensive assessment of CYP3A, CYP2B6, and CYP2C8 drug substrates, and oral contraceptives in healthy participants.

PURPOSE: Midostaurin, approved for treating FLT-3-mutated acute myeloid leukemia and advanced systemic mastocytosis, is metabolized by cytochrome P450 (CYP) 3A4 to two major metabolites, and may inhibit and/or induce CYP3A, CYP2B6, and CYP2C8. Two studies investigated the impact of midostaurin on CYP substrate drugs and oral contraceptives in healthy participants. METHODS: Using sentinel dosing for participants' safety, the effects of midostaurin at steady state following 25-day (Study 1) or 24-day (Study 2) dosing with 50 mg twice daily were evaluated on CYP substrates, midazolam (CYP3A4), bupropion (CYP2B6), and pioglitazone (CYP2C8) in Study 1; and monophasic oral contraceptives (containing ethinylestradiol [EES] and levonorgestrel [LVG]) in Study 2. RESULTS: In Study 1, midostaurin resulted in a 10% increase in midazolam peak plasma concentrations (Cmax), and 3-4% decrease in total exposures (AUC). Bupropion showed a 55% decrease in Cmax and 48-49% decrease in AUCs. Pioglitazone showed a 10% decrease in Cmax and 6% decrease in AUC. In Study 2, midostaurin resulted in a 26% increase in Cmax and 7-10% increase in AUC of EES; and a 19% increase in Cmax and 29-42% increase in AUC of LVG. Midostaurin 50 mg twice daily for 28 days ensured that steady-state concentrations of midostaurin and the active metabolites were achieved by the time of CYP substrate drugs or oral contraceptive dosing. No safety concerns were reported. CONCLUSION: Midostaurin neither inhibits nor induces CYP3A4 and CYP2C8, and weakly induces CYP2B6. Midostaurin at steady state has no clinically relevant PK interaction on hormonal contraceptives. All treatments were well tolerated.

Phase I study of UCN-01 and perifosine in patients with relapsed and refractory acute leukemias and high-risk myelodysplastic syndrome.

BACKGROUND: The PI3K-Akt pathway is frequently activated in acute leukemias and represents an important therapeutic target. UCN-01 and perifosine are known to inhibit Akt activation. METHODS: The primary objective of this phase I study was to determine the maximum tolerated dose (MTD) of UCN-01 given in combination with perifosine in patients with advanced acute leukemias and myelodysplastic syndrome. Secondary objectives included safety, pharmacokinetics, pharmacodynamics, and efficacy. Perifosine 150 mg every 6 h was given orally on day 1 followed by 100 mg once a day continuously in 28-day cycles. UCN-01 was given intravenously over 3 h on day 4 at three dose levels (DL1=40 mg/m(2); DL2=65 mg/m(2); DL3=90 mg/m(2)). RESULTS: Thirteen patients were treated (DL1, n=6; DL2, n=4; DL3, n=3) according to a traditional "3+3" design. Two patients at the DL3 experienced dose-limiting toxicity including grade 3-4 pericardial effusion, hypotension, hyperglycemia, hyperkalemia, constitutional symptoms and grade 5 pneumonitis. Other frequent toxicities were grade 1-2 nausea, diarrhea, vomiting, fatigue and hyperglycemia. The MTD was determined to be UCN-01 65 mg/m(2) with perifosine 100 mg a day. No appreciable direct Akt inhibition could be demonstrated in patients' mononuclear cells using Western blot, however, reduced phosphorylation of the downstream target ribosomal protein S6 in leukemic blasts was noted by intracellular flow cytometry. No objective responses were observed on this study. CONCLUSION: UCN-01 and perifosine can be safely administered, but this regimen lacked clinical efficacy. This approach may have failed because of insufficient Akt inhibition in vivo.

A mechanism-based population pharmacokinetic model for characterizing time-dependent pharmacokinetics of midostaurin and its metabolites in human subjects.

BACKGROUND AND OBJECTIVE: Midostaurin, a novel potent inhibitor of protein kinase C enzyme and class III receptor tyrosine kinases, including Fms-like tyrosine kinase-3 (FLT3) and c-KIT, shows time-dependent pharmacokinetics in human subjects, presumably due to enzyme auto-induction. The purpose of this study was to develop a mechanism-based population pharmacokinetic model to describe the plasma concentration profiles of midostaurin and its metabolites and to characterize the time course of auto-induction. SUBJECTS AND METHODS: Data from 37 diabetic patients who received oral doses of midostaurin (25 mg twice daily, 50 mg twice daily or 75 mg twice daily) for 28 days were analysed using nonlinear mixed-effects modelling. The structural model included a gut compartment for drug input and central and peripheral compartments for midostaurin, with drug output from the central compartment to either of two compartments for the midostaurin metabolites CGP62221 and CGP52421. Different enzyme induction sub-models were evaluated to account for the observed time-dependent decrease in midostaurin concentrations. RESULTS: An enzyme turnover model, with CGP62221 formation (CL(1)) being a linear process but CGP52421 formation (CL(2)) being inducible, was found to be most appropriate. In the pre-induced state, CL(1) and CL(2) of midostaurin were determined to be 1.47 L/h and 0.501 L/h, respectively. At the end of 28 days of dosing, CL(2) was increased by 5.2-, 6.6- and 6.9-fold in the 25 mg, 50 mg and 75 mg groups, respectively, resulting in a 2.1- to 2.5-fold increase in total clearance of midostaurin. The final model estimated a mean maximum fold of induction (E(max)) of 8.61 and a concentration producing 50% of the E(max) (EC(50)) of 1700 ng/mL (approximately 2.9 micromol/L) for CGP52421-mediated enzyme induction. CONCLUSIONS: The population pharmacokinetic model that was developed was able to describe the time-dependent pharmacokinetic profiles of midostaurin and its auto-induction mechanism. Thus it may be useful for designing an appropriate dosage regimen for midostaurin. The unique feature of this model included a precursor compartment that was able to capture the time delays of auto-induction. The use of such precursor extension in the model may be applicable to other drugs showing long time delays in enzyme auto-induction.

Dose- and time-dependent pharmacokinetics of midostaurin in patients with diabetes mellitus.

Midostaurin is a novel potent inhibitor of both protein kinase C and the major receptor for vascular endothelial growth factor involved in angiogenesis, presenting a rationale for its use in diabetic retinopathy. This study evaluated the safety and pharmacokinetics of midostaurin following multiple oral doses of midostaurin for 28 days at 4 dose levels (25 mg bid, 50 mg bid, 75 mg bid, 75 mg tid), as well as a single oral 100-mg dose in patients with diabetes mellitus (n = 9-13 per dose cohort). Pharmacokinetic parameters were determined on days 1 and 28 based on the plasma concentrations of midostaurin and its metabolites, CGP62221 and CGP52421. The plasma exposures (C(max) and AUC(0-tau)) of midostaurin and metabolites increased less than proportionally over the dose range of 25 to 100 mg, showing a 2.2-fold increase after the first dose. Midostaurin concentrations increased during the first 3 to 6 days of dosing, then declined with time (by 30%-50%) until a steady state was achieved, representing an average accumulation factor (R) of 1.7. CGP62221 showed a similar concentration-time pattern as midostaurin (R = 2.5), but CGP52421 accumulated significantly (R = 18.8). A high-fat meal was found to significantly increase the C(max) and AUC(0-12 h) of midostaurin by 1.5-fold (P = .04) and 1.8-fold (P = .01), respectively, compared with taking the drug after an overnight fast. Midostaurin administered at 50 to 225 mg/day appeared to be generally safe in this group of patients. The most common treatment-related adverse events (eg, loose stools, nausea, vomiting, and headache) were found to be dose related, and the frequency increased markedly above the 150-mg/day dose level.

Phase I and pharmacokinetic study of UCN-01 in combination with irinotecan in patients with solid tumors.

PURPOSE: 7-Hydroxystaurosporine (UCN-01) is a protein kinase inhibitor that inhibits several serine-threonine kinases including PKC and PDK1. Due to the preclinical synergistic effects seen with topoisomerase I inhibitors and non-overlapping toxicity, UCN-01 and irinotecan were combined in a dose-finding study designed to determine the maximum tolerated dose (MTD), toxicity profile, and pharmacokinetics (PK) of UCN-01 and irinotecan. METHODS: Patients with incurable solid malignancies received UCN-01 intravenously (IV) as a 3-h infusion on day 1 and irinotecan IV over 90 min on days 1 and 8 of a 21-day cycle. Doses of UCN-01 for subsequent cycles were half the starting dose. Dose level 1 (DL1) consisted of UCN-01 and irinotecan doses of 50 and 60 mg/m(2), respectively. Blood samples were collected in cycle 1 for UCN-01, irinotecan, and irinotecan metabolites. RESULTS: A total of 16 patients were enrolled on the trial at UCN-01/Irinotecan doses of 50/60 mg/m(2) (DL1; n = 1), 70/60 mg/m(2) (DL2; n = 6), 90/60 mg/m(2) (DL3; n = 4), and 70/90 mg/m(2) (DL4; n = 5). Two dose-limiting toxicities were observed each in DL3 and DL4 (2 grade 3 hypophosphatemia, 1 grade 4 hyperglycemia and grade 3 hypophosphatemia, 1 grade 4 febrile neutropenia). Fatigue, diarrhea, nausea, and anorexia were the most prevalent toxicities. No objective responses were documented, and four patients had stable disease for at least ten cycles. The long half-life (292.0 +/- 135.7 h), low clearance (0.045 +/- 0.038 l/h), and volume of distribution (14.3 +/- 5.9 l) observed for UCN-01 are consistent with prior UCN-01 data. There was a significant decrease in C(max) of APC, AUC of APC and SN-38, and AUC ratio of SN-38:irinotecan when comparing days 1 and 8 PK. CONCLUSIONS: APC and SN-38 exposure decreased when administered in combination with UCN-01. The MTD of the combination based on protocol criteria was defined as 70 mg/m(2) of UCN-01 on day 1 and 60 mg/m(2) of irinotecan on days 1 and 8 in a 21-day cycle.

Phase I and pharmacokinetic study of 7-hydroxystaurosporine and carboplatin in advanced solid tumors.

PURPOSE: Based on preclinical data showing synergy between 7-hydroxystaurosporine (UCN-01) and platinum agents, a phase I trial of carboplatin with UCN-01 administered as a 3 h infusion in patients with advanced solid tumors was done. The primary goals of this trial were to evaluate the tolerability of this combination and the pharmacokinetics of UCN-01 when administered over 3 h and to compare the tolerability and pharmacokinetics with previously described schedules. PATIENTS AND METHODS: Patients with advanced solid tumors, good performance status, normal organ function, and no potentially curative therapy were eligible for the trial. Carboplatin was escalated from an area under the curve (AUC) of 3 to an AUC of 5. UCN-01 was escalated from 50 to 90 mg/m(2). RESULTS: Twenty-three patients with advanced solid tumors (20 with prior platinum treatment) received a total of 60 cycles of therapy. Full doses of both agents (carboplatin AUC 5, UCN-01 90 mg/m(2) in cycle 1, 45 mg/m(2) in subsequent cycles) could be administered. The major toxicity noted was hypotension, which could be abrogated with the use of saline prehydration and posthydration. No responses were seen; however, seven patients were able to receive more than two courses of therapy. Of note, two of three patients with refractory, progressive small cell lung cancer were able to receive six cycles of therapy without evidence of progression. One patient experienced resolution of paraneoplastic syndrome of inappropriate antidiuretic hormone. The pharmacokinetic variables C(max) and t(1/2) of the 3 h infusion were essentially identical to those previously observed when UCN-01 was administered over 72 h. The average t(1/2) for cycle 1 was 506 +/- 301 h, and the mean C(max) for all dose levels was >30 micromol/L. The mean AUC over the dosing interval for each dose level ranged from approximately 6,000 to 9,000 micromol/L h. Thus, the AUC of UCN-01 after the 3 h infusion was lower than was observed after a 72 h infusion. CONCLUSION: The regimen of carboplatin and UCN-01 (administered as a 3 h infusion) was well tolerated. Further development of this combination, particularly in small cell lung cancer, is warranted.

Controlled release of a protein kinase inhibitor UCN-01 from liposomes influenced by the particle size.

A protein kinase inhibitor UCN-01 binds with high affinity to human alpha 1-acid glycoprotein (hAGP) which may compromise the drugs therapeutic effectiveness. Liposomal formulations of UCN-01 have been evaluated as a means of reducing the impact of binding to hAGP. However, in an initial study, UCN-01 was released rapidly from liposomes added to rat plasma containing hAGP. The purpose of this study was to develop a liposomal formulation of UCN-01 that only slowly released drug. Liposomes composed of lipids with a high phase transition temperature and having an average particle size of 120 nm and above reduced leaking of UCN-01 when the formulations were evaluated by adding to rat plasma containing hAGP. Furthermore, formulations composed of larger liposomes were also more effective in vivo; in tests in which liposomal preparations were injected together with hAGP into rats, more UCN-01 was retained in liposomes for 24h after administration of 155 nm liposomes as compared to 112 nm liposomes.

Modulation of cell cycle progression in human tumors: a pharmacokinetic and tumor molecular pharmacodynamic study of cisplatin plus the Chk1 inhibitor UCN-01 (NSC 638850).

BACKGROUND: UCN-01, a Chk1 inhibitor, abrogates S and G(2) arrest and enhances cancer cell killing by DNA-damaging drugs in preclinical models. UCN-01 avidly binds alpha1-acid glycoprotein in plasma; whether sufficient drug concentrations are achieved in human tumors is unknown. A phase I trial tested the hypothesis that UCN-01 abrogates cisplatin-induced cell cycle arrest (in tumors) at tolerable doses. METHODS: Patients with advanced cancer received i.v. cisplatin, followed 22 hours later by UCN-01 (3-day continuous i.v. infusion of a 28-day cycle). Platinum was measured by atomic absorption, UCN-01 by high-performance liquid chromatography, and cell cycle progression in tumor biopsies by geminin immunostaining (biomarker for S/G(2) phases of cell cycle). RESULTS: The first two patients treated with cisplatin (20 mg/m(2) plus UCN-01 45 mg/m(2)/d) experienced dose-limiting toxicities (subarachnoid hemorrhage, hyperglycemia, hypoxia, cardiac ischemia, and atrial fibrillation). Following 25% UCN-01 dose reduction, no toxicities greater than grade 2 were seen. Median plasma UCN-01 half-life (T(1/2)) was 405 hours. Salivary UCN-01 concentrations showed a rapid initial decline (median T(1/2alpha), 29.9 hours), followed by a terminal decay parallel to that in plasma. UCN-01 pharmacokinetics, and the timing of clinical toxicities, suggests that UCN-01 is bioavailable despite alpha1-acid glycoprotein binding. Marked suppression of cells in S/G(2) in tumor biopsies was seen by geminin immunohistochemistry, suggesting that UCN-01 is bioavailable at concentrations sufficient to inhibit Chk1. CONCLUSIONS: Cisplatin (30 mg/m(2)), followed 22 hours later by UCN-01 (34 mg/m(2)/d for 3 days), is well tolerated clinically and yields UCN-01 concentrations sufficient to affect cell cycle progression in tumors.

Midostaurin: First Global Approval.

Midostaurin (Rydapt®) is a multikinase inhibitor being developed by Novartis Pharmaceuticals. In April 2017, midostaurin was approved in the USA for the treatment of adult patients with newly diagnosed, FMS-like tyrosine kinase 3 (FLT3) mutation-positive acute myeloid leukaemia (AML) [in combination with standard cytarabine and daunorubicin induction, and cytarabine consolidation], or aggressive systemic mastocytosis (ASM), systemic mastocytosis with associated haematological neoplasm (SM-AHN) or mast cell leukaemia (MCL) [collectively known as advanced SM]. The article summarizes the milestones in the development of midostaurin leading to this first global approval.

Midostaurin for the treatment of adult patients with newly diagnosed acute myeloid leukemia that is FLT3 mutation-positive.

Midostaurin is a multitargeted tyrosine kinase inhibitor (TKI) that potently inhibits activated fms-related tyrosine kinase 3 (FLT3) in the nanomolar range and other kinases including platelet-derived growth factor receptors α (PDGFR- α) and ß (PDGFR- ß), cyclin-dependent kinase, proto-oncogene tyrosine-protein kinase Src, tyrosine-protein kinase Fgr, spleen tyrosine kinase (Syk), KIT proto-oncogene receptor tyrosine kinase and the major vascular endothelial growth factor receptor (VEGFR). Activating mutations in FLT3, which is one of the more common acute myeloid leukemia (AML) mutations, particularly those that result in an FLT3-ITD (internal tandem duplication) mutation, confer poor prognosis and represent a therapeutic target. Small molecule TKIs that vary in potency and selectivity for FLT3 are under investigation. Here, we provide a comprehensive review of the preclinical and clinical activity of midostaurin, a recently approved drug indicated to be used in combination with cytarabine and daunorubicin induction and cytarabine consolidation chemotherapy for the treatment of AML featuring an FLT3 mutation.

Phase I trial of the cyclin-dependent kinase inhibitor and protein kinase C inhibitor 7-hydroxystaurosporine in combination with Fluorouracil in patients with advanced solid tumors.

PURPOSE: Preclinical studies indicate that the cyclin-dependent kinase and protein kinase C inhibitor 7-hydroxystaurosporine (UCN-01) potentiates the cytotoxic effects of fluorouracil (FU). We designed a phase I clinical trial of FU in combination with UCN-01. PATIENTS AND METHODS: FU was administered as a weekly 24-hour infusion. Doses were escalated in successive cohorts according to a modified Fibonacci design. UCN-01 was administered once every 4 weeks, immediately after disconnection from FU, at a dose of 135 mg/m(2) over 72 hours in cycle 1 and 67.5 mg/m(2) over 36 hours in subsequent cycles. FU and UCN-01 pharmacokinetics were obtained on all patients, and thymidylate synthetase (TS) activity was measured in peripheral-blood mononuclear cells by reverse-transcriptase polymerase chain reaction. RESULTS: We escalated the weekly FU dose to 2,600 mg/m(2) in combination with once a month infusions of UCN-01. Dose-limiting toxicity included arrhythmia and syncope. Other toxicities included hyperglycemia, headache, and nausea and vomiting. The mean maximal plasma concentration of UCN-01 was 33.5 micromol/L. There was significant interpatient variability, which correlated with plasma concentrations of alpha-1 acid glycoprotein. FU was rapidly cleared and the dose had no effect on the area under the curve of UCN-01. Changes in TS expression were detectable in peripheral-blood mononuclear cells after administration of UCN-01 but did not correlate with toxicity or activity. We observed no objective response, although seven patients had stable disease, six of whom had received prior fluoropyrimidines. CONCLUSION: The combination of weekly infusions of FU and monthly UCN-01 can be administered safely and warrants further study in phase II trials. The recommended phase II dose of FU in combination with monthly UCN-01 is 2,600 mg/m(2).

On the observed large interspecies overprediction of human clearance ("vertical allometry") of UCN-01: further support for a proposed model based on plasma protein binding.

The prediction of a human clearance (CL) value for UCN-01, an extreme example of vertical allometry (a large overprediction by allometric scaling), was examined using commonly used simple allometry and the "rule of exponents," as well as a newly proposed model, which quantitatively incorporates plasma protein-binding information from rats and humans. Simple allometry and the rule of exponents were shown to overpredict the human CL value of UCN-01 by about 5000- and 1750-fold, respectively. The new model incorporating the ratio of fraction unbound between rats and humans improved the prediction by about 20-fold compared to the rule of exponents. The model is expected to improve if a more accurate measurement of the unbound fraction in human plasma is obtained. The prediction of volume distribution for UCN-01 by allometric scaling was also shown to be dependent on the difference of fraction unbound between animal species and humans. In summary, plasma protein binding has been demonstrated to be an important measure for interspecies scaling of pharmacokinetics.

The cyclin-dependent kinase inhibitor UCN-01 plus cisplatin in advanced solid tumors: a California cancer consortium phase I pharmacokinetic and molecular correlative trial.

BACKGROUND: UCN-01 (7-hydroxy-staurosporine) is a novel antineoplastic agent targeting cyclin-dependent kinases, which shows potent in vitro and in vivo activity against a broad range of tumor types. Our group has previously shown that UCN-01 potentiates the apoptotic response of agents such as cisplatin in vitro by preventing sequence-specific abrogation of G2 arrest caused by DNA-damaging chemotherapies. PATIENTS AND METHODS: This National Cancer Institute-sponsored phase I trial was designed to determine the safety, maximum tolerated dose, and pharmacokinetics of escalating doses of cisplatin in combination with UCN-01 in patients with advanced malignant solid tumors, as well as to do molecular correlative studies on tumor specimens. Cisplatin was infused over 1 hour before UCN-01 (45 mg/m2/d) given as a 72-hour continuous infusion. Escalation of cisplatin was planned through five dose levels at 20, 30, 45, 60, and 75 mg/m2. RESULTS: Ten patients were accrued. Accrual was halted at dose level 2 (cisplatin, 30 mg/m2) due to dose-limiting toxicities consisting of grade 5 sepsis with respiratory failure associated with grade 3 creatinine (one patient) and grade 3 atrial fibrillation (one patient). Plasma and salivary pharmacokinetics of UCN-01 were unaffected by cisplatin. Pretreatment and posttreatment tumor biopsies showed that UCN-01 was active against a key molecular target, the checkpoint kinase Chk1. CONCLUSIONS: This phase I trial failed to achieve targeted therapeutic dose levels of cisplatin when combined with prolonged infusion UCN-01. However, because preclinical data indicate that UCN-01 potentiates response to platinum, further studies with alternative dose schedules of the combination, or with other platinum analogues, are warranted.

Phase I and pharmacokinetic study of PKC412, an inhibitor of protein kinase C.

PURPOSE: N-Benzoyl staurosporine (PKC412) is a protein kinase C inhibitor with antitumor activity in laboratory models. We determined the toxicity of oral PKC412 administered daily for repeat cycles of 28 days. PATIENTS AND METHODS: Thirty-two patients with advanced solid cancers were treated at seven dose levels (12.5 to 300 mg daily) for a total of 68 cycles. RESULTS: The most frequent treatment-related toxicities were nausea, vomiting, fatigue, and diarrhea. At the two top dose levels (225 and 300 mg/d), 15 of 16 patients experienced nausea/vomiting (common toxicity criteria [CTC], version 1), grade 2 in nine of 16 and grade 3 in three of 16 patients; and six of 16 patients developed CTC grade 2 diarrhea. After 1 month of treatment, there were significant reductions in circulating lymphocyte (P <.02) and monocyte (P <.01) counts in patients receiving doses > or = 100 mg/d. Nevertheless, only two patients developed myelosuppression (both grade 2). Of two patients with progressive cholangiocarcinoma, one attained stable disease lasting 4.5 months and one a partial response lasting 4 months. There was a linear relationship between PKC412 dose and area under the curve (0-24 hours) and maximum plasma concentration with marked interpatient variability. The estimated median elimination half-life was 1.6 days (range, 0.9 to 4.0 days), and a metabolite with a median half-life of 36 days was detected. Steady-state PKC412 plasma levels at the top three dose cohorts (150 to 300 mg) were five to 10 times the cellular 50% inhibitory concentration for PKC412 of 0.2 to 0.7 micromol/L. CONCLUSION: PKC412 can be safely administered by chronic oral therapy, and 150 mg/d is suitable for phase II studies. The pharmacokinetics and lack of conventional toxicity indicate that pharmacodynamic measures may be additionally needed to optimize the drug dose and schedule.