A simplified method for bortezomib determination using dried blood spots in combination with liquid chromatography/tandem mass spectrometry.

Bortezomib, a proteinase inhibitor currently used to treat multiple myeloma and mantle cell lymphoma, has a high incidence of adverse reactions and large inter-individual differences in plasma concentrations. A simple, validated LC-MS/MS method for the quantitative analysis of bortezomib in dried blood spot (DBS) samples was developed to provide support for determining the effective concentration range of bortezomib for clinical use. Fifty (i50) µL of spiked blood were added onto Whatman protein saver cards to prepare the DBS samples. Circular cards of 6 mm diameter were punched, extracted by methanol containing the internal standard (apatinib), and injected into the LC-MS/MS system. The method validation included selectivity, linearity, accuracy and precision, stability, matrix effect, recovery and hematocrit. The calibration curve showed correlation coefficient values higher than 0.999 in the range of 0.2 - 20.0 ng/mL for bortezomib. The acceptance criteria of accuracy (relative error < 12.5%) and precision (coefficient of variation < 10.7%) were met in all cases. The matrix effect was<13.2%, and the recovery was between 87.3 and 100.2%. DBS samples were shown to be stable when stored in cold conditions or at room temperature. Different hematocrit values did not significantly affect the accuracy of the measured concentrations. And there are no significant differences between bortezomib concentrations in DBS samples and plasma samples. This new method was successfully used for clinical concentration determinations of bortezomib and can be applied in future therapeutic drug monitoring and pharmacokinetic studies of bortezomib especially in pediatric patients.

A Semi-Mechanistic Population Pharmacokinetic/Pharmacodynamic Model of Bortezomib in Pediatric Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia.

INTRODUCTION: The pharmacokinetics (PK) of the 20S proteasome inhibitor bortezomib are characterized by a large volume of distribution and a rapid decline in plasma concentrations within the first hour after administration. An increase in exposure was observed in the second week of treatment, which has previously been explained by extensive binding of bortezomib to proteasome in erythrocytes and peripheral tissues. We characterized the nonlinear population PK and pharmacodynamics (PD) of bortezomib in children with acute lymphoblastic leukemia. METHODS: Overall, 323 samples from 28 patients were available from a pediatric clinical study investigating bortezomib at an intravenous dose of 1.3 mg/m2 twice weekly (Dutch Trial Registry number 1881/ITCC021). A semi-physiological PK model for bortezomib was first developed; the PK were linked to the decrease in 20S proteasome activity in the final PK/PD model. RESULTS: The plasma PK data were adequately described using a two-compartment model with linear elimination. Increased concentrations were observed in week 2 compared with week 1, which was described using a Langmuir binding model. The decrease in 20S proteasome activity was best described by a direct effect model with a sigmoidal maximal inhibitory effect, representing the relationship between plasma concentrations and effect. The maximal inhibitory effect was 0.696 pmol AMC/s/mg protein (95% confidence interval 0.664-0.728) after administration. CONCLUSION: The semi-physiological model adequately described the nonlinear PK and PD of bortezomib in plasma. This model can be used to further optimize dosing of bortezomib.

Bortezomib pharmacokinetics in tumor response and peripheral neuropathy in multiple myeloma patients receiving bortezomib-containing therapy.

The usefulness of pharmacokinetics of bortezomib for multiple myeloma (MM) with respect to the maximum response to bortezomib and bortezomib-induced peripheral neuropathy (BIPN) development was studied. Maximum response to subcutaneous bortezomib therapy and BIPN occurrence for the first 12 weeks of treatment in 35 MM patients treated by bortezomib-dexamethasone (VD) and bortezomib-melphalan-prednisone (VMP) were evaluated. On day 1 of cycle 1, seven whole-blood samples were collected for 3 h after dosing completion to obtain the maximum plasma concentration and area under the time-concentration curve during 3 h postdose (AUC0-3) in each patient. A total of 35 patients with complete data were analyzed and the overall response rate was 91.4%. Complete response (CR) was observed in 42.9% patients. The maximum plasma concentration (Cmax) was significant for the CR rate in two different models [full model: odds ratio (OR)=1.092; P=0.038, final model: OR=1.081; P=0.038]. In addition, Cmax was associated with a progression-free survival advantage. Overall, 48.6% of patients developed BIPN including peripheral sensory neuropathy and neuralgia. The VMP-treated patients had a higher risk compared with the VD-treated patients (OR=21.662; P=0.029). Cmax had a tendency to affect the occurrence of BIPN (≥grade 2) (OR=1.064; P=0.092). In real-world clinical practice using bortezomib for MM patients, Cmax among pharmacokinetic factors significantly affected the achievement of CR. The VMP-treated patients showed vulnerability to BIPN, suggesting the necessity for more careful monitoring.

Population Pharmacokinetic Analysis of Bortezomib in Pediatric Leukemia Patients: Model-Based Support for Body Surface Area-Based Dosing Over the 2- to 16-Year Age Range.

This population analysis described the pharmacokinetics of bortezomib after twice-weekly, repeat-dose, intravenous administration in pediatric patients participating in 2 clinical trials: the phase 2 AALL07P1 (NCT00873093) trial in relapsed acute lymphoblastic leukemia and the phase 3 AAML1031 (NCT01371981) trial in de novo acute myelogenous leukemia. The sources of variability in the pharmacokinetic parameters were characterized and quantified to support dosing recommendations. Patients received intravenous bortezomib 1.3 mg/m2 twice-weekly, on days 1, 4, and 8 during specific blocks or cycles of both trials and on day 11 of block 1 of study AALL07P1, in combination with multiagent chemotherapy. Blood samples were obtained and the plasma was harvested on day 8 over 0-72 hours postdose to measure bortezomib concentrations by liquid chromatography-tandem mass spectrometry. Concentration-time data were analyzed by nonlinear mixed-effects modeling. Covariates were examined using forward addition (P < .01)/backward elimination (P < .001). Data were included from 104 patients (49%/51% acute lymphoblastic leukemia/acute myelogenous leukemia; 60%/40% aged 2-11 years/12-16 years). Bortezomib pharmacokinetics were described by a 3-compartment model with linear elimination. Body surface area adequately accounted for variability in clearance (exponent 0.97), supporting body surface area-based dosing. Stratified visual predictive check simulations verified that neither age group nor patient population represented sources of meaningful pharmacokinetic heterogeneity not accounted for by the final population pharmacokinetic model. Following administration of 1.3 mg/m2 intravenous bortezomib doses, body surface area-normalized clearance in pediatric patients was similar to that observed in adult patients, thereby indicating that this dose achieves similar systemic exposures in pediatric patients.

A phase I pharmacokinetic study of intraperitoneal bortezomib and carboplatin in patients with persistent or recurrent ovarian cancer: An NRG Oncology/Gynecologic Oncology Group study.

PURPOSE: Intraperitoneal (IP) therapy improves survival compared to intravenous (IV) treatment for women with newly diagnosed, optimally cytoreduced, ovarian cancer. However, the role of IP therapy in recurrent disease is unknown. Preclinical data demonstrated IP administration of the proteasome inhibitor, bortezomib prior to IP carboplatin increased tumor platinum accumulation resulting in synergistic cytotoxicity. We conducted this phase I trial of IP bortezomib and carboplatin in women with recurrent disease. METHODS: Women with recurrent ovarian cancer were treated with escalating doses of IP bortezomib - in combination with IP carboplatin (AUC 4 or 5) every 21days for 6cycles. Pharmacokinetics of both agents were evaluated in cycle 1. RESULTS: Thirty-three women participated; 32 were evaluable for safety. Two patients experienced dose-limiting toxicity (DLT) at the first dose level (carboplatin AUC 5, bortezomib 0.5mg/m2), prompting carboplatin reduction to AUC 4 for subsequent dose levels. With carboplatin dose fixed at AUC 4, bortezomib was escalated from 0.5 to 2.5mg/m2 without DLT. Grade 3/4 related toxicities included abdominal pain, nausea, vomiting, and diarrhea which were infrequent. The overall response rate in patients with measurable disease (n=21) was 19% (1 complete, 3 partial). Cmax and AUC in peritoneal fluid and plasma increased linearly with dose, with a favorable exposure ratio of the peritoneal cavity relative to peripheral blood plasma. CONCLUSION: IP administration of this novel combination was feasible and showed promising activity in this phase I trial of heavily pre-treated women with ovarian cancer. Further evaluation of this IP combination should be conducted.

A phase II trial evaluating the effects and intra-tumoral penetration of bortezomib in patients with recurrent malignant gliomas.

One resistance mechanism in malignant gliomas (MG) involves nuclear factor-κB (NF-κB) activation. Bortezomib prevents proteasomal degradation of NF-κB inhibitor α (NFKBIA), an endogenous regulator of NF-κB signaling, thereby limiting the effects of NF-κB on tumor survival and resistance. A presurgical phase II trial of bortezomib in recurrent MG was performed to determine drug concentration in tumor tissue and effects on NFKBIA. Patients were enrolled after signing an IRB approved informed consent. Treatment was bortezomib 1.7 mg/m(2) IV on days 1, 4 and 8 and then surgery on day 8 or 9. Post-operatively, treatment was Temozolomide (TMZ) 75 mg/m(2) PO on days 1-7 and 14-21 and bortezomib 1.7 mg/m(2) on days 7 and 21 [1 cycle was (1) month]. Ten patients were enrolled (8 M and 2 F) with 9 having surgery. Median age and KPS were 50 (42-64) and 90 % (70-100). The median cycles post-operatively was 2 (0-4). The trial was stopped as no patient had a PFS-6. All patients are deceased. Paired plasma and tumor bortezomib concentration measurements revealed higher drug concentrations in tumor than in plasma; NFKBIA protein levels were similar in drug-treated vs. drug-naïve tumor specimens. Nuclear 20S proteasome was less in postoperative samples. Postoperative treatment with TMZ and bortezomib did not show clinical activity. Bortezomib appears to sequester in tumor but pharmacological effects on NFKBIA were not seen, possibly obscured due to downregulation of NFKBIA during tumor progression. Changes in nuclear 20S could be marker of bortezomib effect on tumor.

LC-MS/MS method for simultaneous determination of thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin in serum of multiple myeloma patients.

Multiple myeloma (MM), a malignant neoplastic serum-cell disorder, has been a serious threat to human health. The determination of 6 commonly used drug concentrations, including thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin, in MM patients was of great clinical interest. Herein, we reported a method for the rapid and simultaneous measurement of the above therapeutics by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method with solid phase extraction. Analysis was performed on a Waters XBridge(®) BEH C18 column (2.5µm, 2.1 mm×50mm), with formic acid aqueous solution and acetonitrile as the mobile phase at flow rate 0.3mL/min. All analytes showed good correlation coefficients (r>0.996), and LLOQ of thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin were 4, 2, 2, 2, 2 and 2ng/mL, respectively. The inter- and intra-day precisions and stability were expressed as variation coefficients within 15% and relative error less than 15%. Dilution effect, carryover and incurred sample reanalysis were investigated according to the 2015 edition Chinese Pharmacopoeia guidelines, as US FDA (2013, revision 1) required. The LC-MS/MS based assay described in this article may improve future clinical studies evaluating common therapeutics for MM treatment.

Panobinostat PK/PD profile in combination with bortezomib and dexamethasone in patients with relapsed and relapsed/refractory multiple myeloma.

PURPOSE: Panobinostat, a potent pan-deacetylase inhibitor, improved progression-free survival (PFS) in patients with relapsed and refractory multiple myeloma when combined with bortezomib and dexamethasone in a phase 3 trial, PANORAMA-1. This study aims to explore exposure-response relationship for panobinostat in this combination in a phase 1 trial, B2207 and contrast with data from historical single-agent studies. METHODS: Panobinostat plasma concentration-time profiles were obtained in patients from PANORAMA-1 (n = 12) and B2207 (n = 12) trials. Overall response rates (ORR) and major adverse events (AE) by panobinostat exposure were investigated in the B2207 trial. Panobinostat PK data from combination trials were contrasted with data from single-agent studies. RESULTS: At maximum tolerated dose (MTD), the geometric mean of panobinostat area under curve from 0 to 24 h (AUC0-24) was 47.5 ng h/mL (77 % CV), and maximum plasma concentration (Cmax) was 8.1 ng/mL (90 % CV). These values were comparable with exposure data obtained in PANORAMA-1, but were 20 % lower than those without dexamethasone, and ∼ 50 % lower from single-agent trials, likely due to enzyme induction by dexamethasone. Higher levels of panobinostat exposure were associated with higher response rates and higher incidences of diarrhea and thrombocytopenia. CONCLUSIONS: Apparent panobinostat exposure-AE and exposure-ORR relationships were observed when combined with bortezomib and dexamethasone in the treatment of patients with relapsed and refractory multiple myeloma. The addition of dexamethasone facilitated best response even though plasma exposure of panobinostat was reduced. Combination with a strong enzyme inducer should be avoided in future trials to prevent further reduction of panobinostat exposure.