Sensitive inductively coupled plasma mass spectrometry assay for the determination of platinum originating from cisplatin, carboplatin, and oxaliplatin in human plasma ultrafiltrate

Improved method for quantification of intact oxaliplatin by ultra high performance liquid chromatography-inductively coupled plasma mass spectrometry: Applications to clinical and speciation studies

Interest is increasing in the use of different liquid chromatography techniques coupled online to mass spectrometry for the quantification of platinum anticancer drugs in human plasma to inform cancer chemotherapy. We developed, validated and studied the application of a method for quantification of intact oxaliplatin in human plasma using ultra high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (UHPLC-ICP-MS). Plasma samples were processed instantly after collection from patients to preserve oxaliplatin speciation by methanol-deproteinization, and storage of diluted supernatants (plasma:methanol 1:2 v/v) at -80 °C. UHPLC separation of intact oxaliplatin and internal standard (carboplatin) was achieved using a C18 column and linear gradient mobile phase (Mobile phase A: water-methanol (97:3 v/v), 0.075 mM sodium dodecyl sulfate, 9.79 nM thallium adjusted to pH 2.5 with trifluoromethanesulfonic acid; Mobile phase B: 100 % methanol (v/v)) with ICP-MS detection to monitor platinum and thallium at m/z 195 and 205, respectively. The limit of quantification was 50 nM in methanol-deproteinized diluted plasma (1:2 v/v). Linearity was established for calibration standards ranging from 50 to 500 nM made in methanol-deproteinized diluted plasma (1:2 v/v), and for dilution of higher concentration samples in blank matrix containing internal standard (final dilution 1:29 v/v). Intra-day and inter-day accuracy ranged from 96.8 to 103 % of nominal concentration and precision from 0.62 to 2.49 % coefficient of variation. Recovery was complete and a matrix effect confirmed the requirement for matrix-matched standards. Intact oxaliplatin was stable during storage for at least 473 days, and during analysis, in methanol-deproteinized diluted plasma (1:2 v/v). The method was applied to determining the plasma concentrations of intact oxaliplatin in patients undergoing cancer chemotherapy, and studies of oxaliplatin degradation in vitro. This improved method based on UHPLC-ICP-MS will allow more specific, efficient and reliable quantification of intact oxaliplatin in human plasma.

Use of Sodium Thiosulfate as an Otoprotectant in Patients With Cancer Treated With Platinum Compounds: A Review of the Literature

PURPOSE

Hearing loss occurs in 50%-70% of children treated with cisplatin. Scientific efforts have led to the recent approval of a pediatric formula of intravenous sodium thiosulfate (STS) for otoprotection by the US Food and Drug Administration, the European Medicines Agency, and the Medicines and Health Regulatory Authority in the United Kingdom. To inform stakeholders regarding the clinical utility of STS, the current review summarizes available literature on the efficacy, pharmacokinetics (PK), and safety of systemic STS to minimize cisplatin-induced hearing loss (CIHL).

DESIGN

A comprehensive narrative review is presented.

RESULTS

Thirty-one articles were summarized. Overall, systemic STS effectively reduces CIHL in the preclinical and controlled clinical study settings, in both adults and children with cancer. The extent of CIHL reduction depends on the timing and dosing of STS in relation to cisplatin. Both preclinical and clinical data suggest that systemic STS may affect plasma platinum levels, but studies are inconclusive. Delayed systemic administration of STS, at 6 hours after the cisplatin infusion, does not affect cisplatin-induced inhibition of tumor growth or cellular cytotoxicity in the preclinical setting, nor affect cisplatin efficacy and survival in children with localized disease in the clinical setting.

CONCLUSION

Systemic administration of STS effectively reduces the development and degree of CIHL in both the preclinical and clinical settings. More studies are needed on the PK of STS and cisplatin drug combinations, the efficacy and safety of STS in patients with disseminated disease, and the ability of STS to prevent further deterioration of pre-established hearing loss.

Using HPLC for the determination of platinum drugs in biological matrixes after derivatization with diethyldithiocarbamate

Challenges and pitfalls in the application of diethyldithiocarbamate derivatization for LC analysis of cisplatin and oxaliplatin, as well as the suitability of this method for different biological matrices with implications for use in routine practice have been identified. The LC of platinum drugs presents a significant challenge. They are polar compounds with poor retention on reverse phase packings. Cisplatin also exhibits poor absorption in UV and ionization in mass spectrometry. Therefore, we developed and optimized a derivatization approach for the LC analysis of total platinum in plasma, plasma ultrafiltrate, peritoneal fluid, and urine. Derivatization in urine proved to be difficult due to the complexity of the matrix, and extended testing was required. Our results highlight the important issues affecting the efficiency, reliability, and suitability of platinum drug derivatization. Although precolumn derivatization is less selective than its postcolumn counterpart, the application of precolumn derivatization is a simple, rapid, and universal approach for the determination of platinum drugs by HPLC. One of its major advantages is that it allows a more affordable analysis using UV detection without the need for additional high-end instrumentation such as a MS detector.

The association of cisplatin pharmacokinetics and skeletal muscle mass in patients with head and neck cancer: The prospective PLATISMA study

BACKGROUND

Locally advanced head and neck squamous cell carcinoma (HNSCC) is commonly treated with cisplatin-based chemoradiotherapy (CRT). Cisplatin is associated with severe toxicity, which negatively affects survival. In recent years, a relationship between low skeletal muscle mass (SMM) and increased toxicity has been described. This increased toxicity may be related to altered cisplatin distribution and binding in the fat-free body mass of which SMM is the largest contributor. This study aims to investigate the association between cisplatin pharmacokinetics and SMM in patients with HNSCC.

METHODS

We performed a prospective observational study in patients with HNSCC treated with CRT. Patients received standard-of-care chemotherapy with three cycles of cisplatin at a dose of 100 mg/m² per cycle. Quantitative data on SMM, measured on computed tomography scans and cisplatin pharmacokinetics (total and ultrafilterable plasma concentrations) were collected, as well as data on toxicity.

RESULTS

A total of 45 evaluable patients were included in the study. A large proportion of the study population had a low SMM (46.7%). The majority of patients (57.8%) experienced cisplatin dose-limiting toxicities. Pharmacokinetic analysis showed a significant relationship between cisplatin pharmacokinetics and SMM, weight, fat-free mass and body surface area (p < 0.005). In a simulation, patients with a low SMM (<25.8 kg) were predicted to reach higher-bound cisplatin concentrations.

CONCLUSION

We found an association between cisplatin pharmacokinetics and SMM; however, this relationship was also seen between cisplatin pharmacokinetics and other body composition descriptors.

Full-dose cisplatin chemotherapy combined with hemodialysis in a patient with impaired renal function and a mediastinal germ cell tumor

Cisplatin is the first choice treatment in mediastinal germ cell tumors. However, concerns regarding increased toxicity of cisplatin hamper its administration in patients with impaired renal function. We describe a 42-year-old man with chronic kidney disease stage 4 who was diagnosed with a mediastinal germ cell tumor and metastases in lung and brain. Treatment with cisplatin-etoposide was considered essential for a chance of cure. In order to administer the full cisplatin dose, 4-hour hemodialysis sessions were performed after each cisplatin infusion. During treatment cycle 3, 4 and 5, total and unbound plasma platinum concentrations were measured. Trough concentrations and half-life were at the higher end of the range of those observed in patients with adequate renal function who received the same dose of cisplatin. Hemodialysis aided platinum clearance, although our patient was also able to clear some platinum by his own renal function. With this full dose treatment, our patient obtained a favorable tumor response, with a strong decrease of beta-human chorionic gonadotropin and tumor size. The side effects experienced by our patient were serious, although not worse than what could be expected with this type of treatment. His renal function remained stable during the treatment period.

Transtympanic Sodium Thiosulfate for Prevention of Cisplatin-Induced Ototoxicity: A Randomized Clinical Trial

OBJECTIVES

To determine safety, feasibility, and preliminary activity of transtympanic injection of sodium thiosulfate (STS) against cisplatin-induced hearing loss (CIHL).DESIGN Randomized controlled trial.SETTING Tertiary cancer hospital.PATIENTS Adults to be treated with high-dose cisplatin (≥ 75 mg/m2).INTERVENTION Selected by randomization, 0.1 M STS gel on one side and placebo gel on the other side was transtympanically applied to the middle ear 3 hours before cisplatin administration. After amendment, the placebo ear was left untreated.

MAIN OUTCOME MEASURE

Primary outcome was safety and feasibility. Secondary outcomes included pharmacokinetic analysis of systemic cisplatin and preliminary activity of STS. Clinically relevant CIHL was defined as a ≥ 10 dB threshold shift at pure-tone average 8-10-12.5 kHz (PTA8-12.5). Response to STS was defined as a threshold shift at PTA8-12.5 in the STS-treated ear of ≥ 10 dB smaller than the untreated ear.

RESULTS

Twelve patients were treated. Average CIHL at PTA8-12.5 was 12.7 dB in untreated ears and 8.8 dB SPL in STS-treated ears (p = 0.403). Four patients did not develop CIHL. Four out of eight patients with CIHL responded to STS: CIHL at PTA8-12.5 in STS-treated ears was 18.4 dB less compared to untreated ears (p = 0.068). Grade 1 adverse events were reported. Pharmacokinetic results were available for 11 patients.

CONCLUSION

Transtympanic application of STS was safe and feasible. Based on our pharmacokinetic analysis, we postulate that transtympanic STS does not interfere with the systemically available cisplatin. Our results provide a preliminary proof of concept for transtympanic application of STS in preventing CIHL and warrants further evaluation on a larger scale.

A Phase I dose-escalation study of two cycles carboplatin-olaparib followed by olaparib monotherapy in patients with advanced cancer

Preclinical studies have shown synergistic effects when combining PARP1/2 inhibitors and platinum drugs in BRCA1/2 mutated cancer cell models. After a formulation change of olaparib from capsules to tablets, we initiated a dose finding study of olaparib tablets bidaily (BID) continuously with carboplatin to prepare comparative studies in this patient group. Patients were included in a 3 + 3 dose‐escalation schedule: olaparib 25 mg BID and carboplatin area under the curve (AUC) 3 mg*min/mL d1/d22, olaparib 25 mg BID and carboplatin AUC 4 mg*min/mL d1/d22, followed by increasing dose‐levels of olaparib from 50 mg BID, 75 mg BID, to 100 mg BID with carboplatin at AUC 4 mg*min/mL d1/d22. After two cycles, patients continued olaparib 300 mg BID as monotherapy. Primary objective was to assess the maximum tolerable dose (MTD). Twenty‐four patients with a confirmed diagnosis of advanced cancer were included. Most common adverse events were nausea (46%), fatigue (33%) and platelet count decrease (33%). Dose‐level 3 (olaparib 75 mg BID and carboplatin AUC 4 mg*min/mL; n = 6) was defined as MTD. Fourteen out of 24 patients (56%) had a partial response as best response (RECIST 1.1). Systemic exposure of the olaparib tablet formulation appeared comparable to the previous capsule formulation with olaparib tablet AUC_0‐12 of 16.3 μg/mL*h at MTD. Polymers of ADP‐ribose levels in peripheral blood mononuclear cells were reduced by 98.7% ± 0.14% at Day 8 compared to Day 1 for dose‐level 3. Olaparib tablets 75 mg BID and carboplatin AUC 4 mg*min/mL for two cycles preceding olaparib monotherapy 300 mg is a feasible and tolerable treatment schedule for patients with advanced cancer.

What's new?

Preclinical studies have shown synergistic effects when combining PARP1/2‐inhibitors and platinum drugs in BRCA1/2 mutated cancer cell models. This phase I trial of olaparib tablets combined with carboplatin in advanced cancer patients showed that the combination has an acceptable side‐effect profile. The maximum tolerable dose was olaparib tablets 75 mg BID and carboplatin AUC 4 mg*min/ml. The observed preliminary anti‐tumor activity was encouraging, with 58% of patients having a decrease in tumor volume of more than 30%. This study shows that the tablet formulation of olaparib can be administered safely in combination with carboplatin, compared to the previous capsule formulation.

Diagnostic yield of colonoscopy surveillance in testicular cancer survivors treated with platinum-based chemotherapy: study protocol of a prospective cross-sectional cohort study

Background

Testicular cancer (TC) survivors have an increased risk of various second primary malignancies. A recent cohort study detected an increased risk of colorectal cancer (CRC) in TC survivors treated with platinum-based chemotherapy with a hazard ratio of 3.9. CRC risk increased with higher cisplatin-dose. We know that colonoscopy surveillance in high-risk populations results in reduced incidence and mortality of CRC. TC survivors treated with platinum-based chemotherapy can potentially benefit from colonoscopy surveillance; however, to which extent is unknown. Furthermore, the pathogenesis of these secondary CRCs is unknown, and better insights into the carcinogenesis may affect surveillance decisions.

Methods

This prospective multicenter study will be performed in four Dutch hospitals. TC survivors are eligible if treated with ≥ 3 cycles of cisplatin before age 50. Colonoscopy will be performed ≥ 8 years after initial treatment (minimum and maximum ages at colonoscopy, 35 and 75 years, respectively). The primary aim of the study is the diagnostic yield of advanced neoplasia detected during colonoscopy. As secondary aim, we will evaluate the molecular profile of advanced colorectal neoplasia and will assess current platinum levels in blood and urine and correlate blood-platinum levels with prevalence of colorectal lesions. Furthermore, we will investigate effectiveness of fecal immunochemical testing (FIT) and burden of colonoscopy by two questionnaires. Demographic data, previous history, results of colonoscopy, hemoglobin level of FIT and results of molecular and platinum levels will be obtained. Yield of colonoscopy will be determined by detection rate of adenoma and serrated lesions, advanced adenoma detection rate and CRC detection rate. The MISCAN model will be used for cost-effectiveness analyses of CRC surveillance. With 234 participants undergoing colonoscopy, we can detect an absolute difference of 6% of advanced neoplasia with 80% power.

Discussion

TC survivors treated with cisplatin-based chemotherapy can benefit from CRC surveillance. Evaluation of the diagnostic performance and patient acceptance of CRC surveillance is of importance to develop surveillance recommendations. Insight into the carcinogenesis of cisplatin-related advanced colorectal lesions will contribute to CRC prevention in the increasing number of TC survivors. The results may also be important for the many other cancer survivors treated with platinum-based chemotherapy.

Trial registration

Clinical Trials: NCT04180033, November 27, 2019, https://clinicaltrials.gov/ct2/show/NCT04180033.

Fast and reliable ICP-MS quantification of palladium and platinum-based drugs in animal pharmacokinetic and biodistribution studies

Palladium-(Pd)-based drugs are emerging as alternatives to platinum (Pt) anticancer chemotherapeutics, which increases the need for efficient and suitable procedures of Pd analysis in reduced amounts of pre-clinical animal samples. Herein, an ICP-MS (inductively coupled plasma-mass spectrometry) method was developed and validated for simple and fast analysis of Pd/Pt-based drugs in 11 distinct biological matrices (adipose tissue, muscle, liver, kidney, spleen, testis, heart, lungs, brain, blood and serum). The critical variables affecting sample preparation and Pd/Pt extraction were optimized using two-level (2^k) factorial and central composite designs. Biological samples (50 mg) were digested in closed tubes with a screw cap, using a 3 : 1 (v/v) mixture of nitric acid (900 μL) and hydrochloric acid (300 μL) for 60 min in a 90 °C water bath. Full method validation using in-house materials showed a LOD of 0.001 μg L^-1, linear dynamic range from 0.025-10 μg L^-1 (R² = 0.9999 for Pd; R² = 0.9998 for Pt), good repeatability (CV: 0.02-1.9%) and intermediate precision (CV: 0.52-1.53%) for both the studied metals. The accuracy ranged from 83.5-105.1% considering microwave-assisted digestion as the reference method. The developed and validated method allows the processing of hundreds of biological samples simultaneously, with low reagent and sample consumption. Therefore, the method is highly suitable for analysis of novel Pd/Pt-based drugs in pharmaco-toxicokinetic and biodistribution animal studies that involve a large number of multi-organ samples.

Diversity of dose-individualization and therapeutic drug monitoring practices of platinum compounds: a review

Introduction: Platinum-derived drugs are commonly used for the treatment of solid tumors. The differences in chemical structures of these molecules lead to different pharmacological properties, in terms of indication, efficacy, and toxicity. Their pharmacokinetics (PK) differ according to their respective renal elimination and have led to many studies investigating their dose optimization. Area covered: This review attempts to summarize and compare PK and pharmacodynamics of cisplatin, carboplatin, and oxaliplatin, with an emphasis on differences of dose calculations and opportunities for therapeutic drug monitoring (TDM) in various patient populations. Expert opinion: Although cisplatin and carboplatin can be considered as analogs since they share the same DNA interacting properties, the slower hydrolysis of the latter results in a better safety profile. Carboplatin is the only drug in oncology to be administrated according to a target area under the curve of concentration versus time, considering that its PK variability is almost fully explained by renal function, not by body size. This enables individual dosing based on predicted carboplatin clearance (along with patients renal characteristics) or on actual clearance with TDM, especially in a high-dose protocol.

Cisplatin and carboplatin pharmacokinetics in a pediatric patient with hepatoblastoma receiving peritoneal dialysis

Purpose

Cisplatin and carboplatin are frequently used drugs in the treatment of pediatric hepatoblastoma. Dosing guidelines for these drugs in children requiring peritoneal dialysis are lacking. Here, we describe the case of a 3-year-old boy with pre-existing end-stage renal disease on peritoneal dialysis, requiring treatment with cisplatin and carboplatin for hepatoblastoma.

Methods

Pharmacokinetic data were generated to support clinical dosing decisions, with the aim of adequate exposure and minimal toxicity. In the first chemotherapy cycle, 25% of the standard cisplatin dose and 75% of the carboplatin dose, calculated using the pediatric Calvert formula, were administered. Free platinum concentrations were determined in plasma ultrafiltrate and dialysate samples drawn after administration of cis- and carboplatin.

Results

Cisplatin was well tolerated and the observed AUC of cisplatin were 15.3 and 14.3 mg/L h in cycles 1 and 3, respectively. The calculated AUC of carboplatin in cycle 1 (9.8 mg/mL min) exceeded target AUC of 6.5 mg/mL min and toxicity was observed; therefore, the dose was reduced in cycles 2 and 3. The observed AUC in cycles 2 and 3 was 5.4 and 5.7 mg/mL min respectively. Platinum concentrations in the dialysate showed that 3–4% of the total dose of cisplatin and 10–12% of the total dose of carboplatin were excreted via peritoneal dialysis. Chemotherapy enabled extended hemihepatectomy and complete remission was achieved.

Conclusion

This report shows that it is feasible to measure AUCs for both drugs and to individualize the dose of these drugs according to the PK results and clinical parameters. Our advice for future cases would be to calculate the starting dose of carboplatin using the (pediatric) Calvert formula, assuming a dialytic clearance of zero, and to adjust the dose if required, based on therapeutic drug monitoring.

Systemic exposure of oxaliplatin and docetaxel in gastric cancer patients with peritonitis carcinomatosis treated with intraperitoneal hyperthermic chemotherapy

In the PERISCOPE I study, gastric cancer patients with limited peritoneal dissemination were treated with systemic chemotherapy followed by (sub)total gastrectomy, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) with 460 mg/m² hyperthermic oxaliplatin followed by normothermic docetaxel in escalating doses (0, 50, 75 mg/m²). In total, 25 patients completed the study protocol. Plasma samples were collected before the start of the HIPEC procedure, after oxaliplatin washing, after docetaxel washing and the following morning. Median peak plasma concentrations were 5.5∗10^-3 mg/ml for oxaliplatin, 89∗10^-6 mg/ml for docetaxel (dose 50 mg/m²) and 113∗10^-6 mg/ml for docetacel (dose 75 mg/m2). The following morning median plasma concentrations were 32% and 4% of the measured peak concentrations for oxaliplatin and docetaxel, respectively. For both cytostatic agents, no correlation was found between intraperitoneal fluid concentration and peak plasma concentration. High doses oxaliplatin and docetaxel can be given intraperitoneally without causing potentially toxic systemic concentrations.

How versatile is the use of ultrafiltration to study biointeractions of therapeutic metallodrugs?

For a representative number of approved or investigational anticancer metallodrugs varying in lipophilicity, unspecific adsorption onto ultracentrifugal filter units was studied. It was found that for fairly hydrophilic compounds, such as cisplatin and oxaliplatin, the binding to filters does not substantially affect their amount measured (by ICP-MS) after ultrafiltration (>95%). In the case of metal complexes with moderate lipophilicity (log P > -0.1), adsorption effects turn out to be substantial. This might impede using ultrafiltration for studying the transformations of such drugs in human serum, unless they are rapidly converted into the protein adducts. The adsorption-suppressing effect of proteins was proved for indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] whose recovery from the filters was 61 and 14% in free and HSA-bound form, respectively.

Intravenous lidocaine affects oxaliplatin pharmacokinetics in simultaneous infusion

BACKGROUND

Oxaliplatin is a chemotherapeutic agent used to treat malignancies of the gastrointestinal tract. Neuropathy is a frequent dose-limiting side-effect of oxaliplatin therapy, without preventive or curative strategies. Concomitant administration of intravenous lidocaine could be a promising treatment. However, the effect of intravenous lidocaine on oxaliplatin pharmacokinetics was never studied before. We evaluated the effect of lidocaine on the area under the curve and C_max of oxaliplatin as a part of a larger study addressing the prevention and treatment of oxaliplatin induced peripheral neuropathy with lidocaine.

METHODS

In this prospective cross-over trial, patients received an oxaliplatin cycle with and without lidocaine (bolus 1.5 mg kg^-1 followed by 1.5 mg kg^-1 h^-1 in 3 h). Levels of oxaliplatin, measured as ultrafiltrable platinum were determined at 10 min after cessation of oxaliplatin infusion and hourly thereafter. Outcomes are the difference in area under the curve of oxaliplatin (primary) and the difference in the C_max of oxaliplatin (secondary).

RESULTS

No difference in the %Δ area under the curve of oxaliplatin (-2.40 ± 7.66, 90% CI +10.50 to -15.31) was found. However, %Δ C_max of oxaliplatin (-28.72 ± 6.01, 90% CI -18.59 to -38.85) was lower to a statistically significant extent in the chemotherapy cycle with lidocaine. No (serious) adverse events were reported.

CONCLUSIONS

Lidocaine does not affect the area under the curve of oxaliplatin, which is the most important parameter in drug interaction studies and for oxaliplatin treatment effect. The lower C_max in the chemotherapeutic cycle with lidocaine is significant and remarkable, but with an unknown exact mechanism or clinical significance, making further research desirable.

Real-time detection of carboplatin using a microfluidic system

A novel on-line microfluidic assay for the chemotherapy agent carboplatin will allow sensitive detection of the drug directly applied to the tumour as it emerges from the tumour into healthy tissue.

A microfluidic sensor system based on a carbon nanotube-epoxy composite electrode was fabricated to allow detection of the presence of the anti-cancer drug carboplatin in healthy tissue in real time during chemotherapy. Detection of carboplatin was carried out by observing the effects of the drug on the differential pulse voltammetry of free purine bases using a novel carbon nanotube-epoxy composite electrode. In free solution these electrodes performed better than glassy carbon electrodes for oxidation of the free purine bases AMP and GMP, and than DNA-modified carbon nanotube-epoxy composite sensors for detection of carboplatin. On-line carboplatin detection was performed using a computer-controlled microfluidic platform. The methodology for on-line carboplatin detection was optimised in terms of the analysis time and to allow repeated carboplatin measurement using the same electrode. Microdialysis sampling and our microfluidic platform were combined to give a proof-of-concept system for real-time carboplatin detection with a limit of detection of 0.014 μM carboplatin in the sampled media. This paper is dedicated to Craig Lunte's pioneering work in analysis and microdialysis.

Intraductal cisplatin treatment in a BRCA-associated breast cancer mouse model attenuates tumor development but leads to systemic tumors in aged female mice

BRCA deficiency predisposes to the development of invasive breast cancer. In BRCA mutation carriers this risk can increase up to 80%. Currently, bilateral prophylactic mastectomy and prophylactic bilateral salpingo-oophorectomy are the only preventive, albeit radical invasive strategies to prevent breast cancer in BRCA mutation carriers. An alternative non-invasive way to prevent BRCA1-associated breast cancer may be local prophylactic treatment via the nipple.

Using a non-invasive intraductal (ID) preclinical intervention strategy, we explored the use of combined cisplatin and poly (ADP)-ribose polymerase 1 (PARP1) inhibition to prevent the development of hereditary breast cancer. We show that ID cisplatin and PARP-inhibition can successfully ablate mammary epithelial cells, and this approach attenuated tumor onset in a mouse model of Brca1-associated breast cancer from 153 to 239 days. Long-term carcinogenicity studies in 150 syngeneic wild-type mice demonstrated that tumor incidence was increased in the ID treated mammary glands by 6.3% due to systemic exposure to cisplatin. Although this was only evident in aged mice (median age = 649 days), we conclude that ID cisplatin treatment only presents a safe and feasible local prevention option if systemic exposure to the chemotherapy used can be avoided.

Antineoplastic drugs and their analysis: a state of the art review

We provide an overview of the analytical methods available for the quantification of antineoplastic drugs in pharmaceutical formulations, biological and environmental samples.

Sexual differentiation and reproductive development of female rat offspring after paternal exposure to the anti-tumor pharmaceutical cisplatin

Cisplatin (CP) is used to treat a number of cancers, including testicular cancer. Studies indicate that CP-treatment can impair spermatogenesis in humans and rodents by germ cell DNA binding, through different modes of action. CP-paternal exposure resulted in adverse effects in F1 male offspring. In this study, F1 female offspring was assessed for reproductive development after CP-paternal exposure. Peri-pubertal male rats, treated with 1mg/Kg/day of CP or vehicle for 3 weeks, were mated with unexposed females. F1 female offspring of CP-treated fathers showed a decrease in fetal ovary germ cells, in estrous cycle length and FSH levels, and an increase in the percentage of antral follicles in adults. Based on our previous results and the findings of the present work we concluded that CP-paternal exposure leads to adverse effects on rat male and female reproductive development, raising concern, in humans, for children born to men exposed to CP.

Subunit composition of VRAC channels determines substrate specificity and cellular resistance to Pt-based anti-cancer drugs

Although platinum‐based drugs are widely used chemotherapeutics for cancer treatment, the determinants of tumor cell responsiveness remain poorly understood. We show that the loss of subunits LRRC8A and LRRC8D of the heteromeric LRRC8 volume‐regulated anion channels (VRACs) increased resistance to clinically relevant cisplatin/carboplatin concentrations. Under isotonic conditions, about 50% of cisplatin uptake depended on LRRC8A and LRRC8D, but neither on LRRC8C nor on LRRC8E. Cell swelling strongly enhanced LRRC8‐dependent cisplatin uptake, bolstering the notion that cisplatin enters cells through VRAC. LRRC8A disruption also suppressed drug‐induced apoptosis independently from drug uptake, possibly by impairing VRAC‐dependent apoptotic cell volume decrease. Hence, by mediating cisplatin uptake and facilitating apoptosis, VRAC plays a dual role in the cellular drug response. Incorporation of the LRRC8D subunit into VRAC substantially increased its permeability for cisplatin and the cellular osmolyte taurine, indicating that LRRC8 proteins form the channel pore. Our work suggests that LRRC8D‐containing VRACs are crucial for cell volume regulation by an important organic osmolyte and may influence cisplatin/carboplatin responsiveness of tumors.

Multidrug Resistance-Associated Protein 2 (MRP2) Mediated Transport of Oxaliplatin-Derived Platinum in Membrane Vesicles

The platinum-based anticancer drug oxaliplatin is important clinically in cancer treatment. However, the role of multidrug resistance-associated protein 2 (MRP2) in controlling oxaliplatin membrane transport, in vivo handling, toxicity and therapeutic responses is unclear. In the current study, preparations of MRP2-expressing and control membrane vesicles, containing inside-out orientated vesicles, were used to directly characterise the membrane transport of oxaliplatin-derived platinum measured by inductively coupled plasma mass spectrometry. Oxaliplatin inhibited the ATP-dependent accumulation of the model MRP2 fluorescent probe, 5(6)-carboxy-2,'7'-dichlorofluorescein, in MRP2-expressing membrane vesicles. MRP2-expressing membrane vesicles accumulated up to 19-fold more platinum during their incubation with oxaliplatin and ATP as compared to control membrane vesicles and in the absence of ATP. The rate of ATP-dependent MRP2-mediated active transport of oxaliplatin-derived platinum increased non-linearly with increasing oxaliplatin exposure concentration, approaching a plateau value (Vmax) of 2680 pmol Pt/mg protein/10 minutes (95%CI, 2010 to 3360 pmol Pt/mg protein/10 minutes), with the half-maximal platinum accumulation rate (Km) at an oxaliplatin exposure concentration of 301 μM (95% CI, 163 to 438 μM), in accordance with Michaelis-Menten kinetics (r² = 0.954). MRP2 inhibitors (myricetin and MK571) reduced the ATP-dependent accumulation of oxaliplatin-derived platinum in MRP2-expressing membrane vesicles in a concentration-dependent manner. To identify whether oxaliplatin, or perhaps a degradation product, was the likely substrate for this active transport, HPLC studies were undertaken showing that oxaliplatin degraded slowly in membrane vesicle incubation buffer containing chloride ions and glutathione, with approximately 95% remaining intact after a 10 minute incubation time and a degradation half-life of 2.24 hours (95%CI, 2.08 to 2.43 hours). In conclusion, MRP2 mediates the ATP-dependent active membrane transport of oxaliplatin-derived platinum. Intact oxaliplatin and its anionic monochloro oxalate ring-opened intermediate appear likely candidates as substrates for MRP2-mediated transport.

Dosing of carboplatin in a patient with amputated legs: A case report

Carboplatin is a platinum derivative that is commonly used in combination chemotherapy for treatment of several malignancies, including small-cell lung carcinoma (SCLC). Because the estimated glomerular filtration rate, and therefore the carboplatin dose, is based on the serum creatinine level, dosing of carboplatin for amputees is a challenge. This case report describes how serum carboplatin levels were used to determine the most suitable carboplatin dose for an amputee. The patient received four cycles of etoposide in combination with carboplatin area under the curve = 5 mg·min/ml, with a dose reduction of 25% and concurrent radiotherapy. The measured area under the curve was found to be 3.41 mg·min/ml, while the target area under the curve was 3.75 mg·min/ml (75% of 5 mg·min/ml). Therefore, for the next cycles, the carboplatin dose was calculated using the Calvert formula. No recurrence of disease was seen within two years after completion of therapy. This case demonstrates that therapeutic drug monitoring can successfully be used to determine the carboplatin dose for an amputee.

Phase I dose-escalation study and population pharmacokinetic analysis of fixed dose rate gemcitabine plus carboplatin as second-line therapy in patients with ovarian cancer

OBJECTIVE

This phase I study of fixed dose rate (FDR) gemcitabine and carboplatin assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, pharmacokinetic (PK)/pharmacodynamic (PD) profile and preliminary anti-tumor activity in patients with recurrent ovarian cancer (OC).

METHODS

Patients with recurrent OC after first line treatment were treated with carboplatin and FDR gemcitabine (infusion speed 10mg/m(2)/min) on days 1, 8 and 15, every 28 days. Pharmacokinetics included measurement of platinum concentrations in plasma ultrafiltrate (pUF) and plasma concentrations of gemcitabine (dFdC) and metabolite dFdU. Intracellular levels of dFdC triphosphate (dFdC-TP), the most active metabolite of gemcitabine, were determined in peripheral blood mononuclear cells (PBMCs). Population pharmacokinetic modeling and simulation were performed to further investigate the optimal schedule.

RESULTS

Twenty three patients were enrolled. Initial dose escalation was performed using FDR gemcitabine 300 mg/m(2) (administered at infusion speed of 10 mg/m(2)/min) combined with carboplatin AUC 2.5 and 3. Excessive bone marrow toxicity led to a modified dose escalation schedule: carboplatin AUC 2 and dose escalation of FDR gemcitabine (300 mg/m(2), 450 mg/m(2), 600 mg/m(2) and 800 mg/m(2)). DLT criteria as defined per protocol prior to the study were not met with carboplatin AUC 2 in combination with FDR gemcitabine 300-800 mg/m(2) because of myelosuppressive dose-holds (especially thrombocytopenia and neutropenia).

CONCLUSIONS

FDR gemcitabine in combination with carboplatin administered in this 28 days schedule resulted in increased grade 3/4 toxicity compared to conventional 30-minute infused gemcitabine. A two weekly schedule (chemotherapy on days 1 and 8) would be more appropriate.

Inductively coupled plasma-MS in drug development: bioanalytical aspects and applications

The vast majority of today's modern bioanalytical methods for pharmacokinetic, pharmacodynamic and immunogenicity purposes are based on LC-MS/MS and immunoanalytical approaches. Indeed, these methodologies are suitable for a wide range of molecules from small to large. For a smaller but not insignificant group of compounds, LC-MS/MS is not suitable - or in some cases much less suitable - as a reliable bioanalytical methodology, and inductively coupled plasma (ICP)-MS is a more appropriate methodology. ICP-MS is one of these less widely used techniques in drug development. This methodology is predominantly used for elemental bioanalysis for pharmacokinetics, for imaging purposes, for mass-balance, food-effect and biomarker studies. In addition, in the last couple of years an increasing number of applications has been published, where ICP-MS and its various hyphenations (LC-ICP-MS, CE-ICP-MS) have been used for speciation/metabolism and proteomics studies. Here, the analytical potential, the quantitative bioanalytical aspects, the various modes of operation and the challenges of the application of ICP-MS in life sciences applications are given. This includes an overview of recent applications in this area in scientific literature, the various hyphenation possibilities and their application areas and the analysis of the various sample matrices applicable to these fields. It also provides a brief outlook of where the potential of this technique lies in the future of regulated bioanalysis and drug development.

Pharmacokinetics, tissue distribution, and plasma protein binding study of platinum originating from dicycloplatin, a novel antitumor supramolecule, in rats and dogs by ICP-MS

Dicycloplatin, as a new antitumor supramolecule, was considered to have higher solubility and higher stability compared with carboplatin. The aim of the present study was to evaluate the pharmacokinetic characteristics of platinum originating from dicycloplatin. A rapid, sensitive, and specific method with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of platinum in bio-samples. The study was performed in male rats and dogs at a single dose of 10 and 5 mg kg(-1) separately by intravenous injection. Pharmacokinetic parameters were calculated by non-compartmental method, and the dose of platinum was used in the calculation of these parameters. Results showed that plasma concentrations of platinum began to decrease rapidly initially but decline slowly with a long terminal phase. The mean half-life was 27.39 and 100.98 and clearance was 0.77 and 0.08 L/h/kg for rats and dogs separately. Tissue distribution showed that platinum originating from dicycloplatin had a certain distribution in testis and prostate. Plasma protein binding proportion of platinum was increased with time. In conclusion, this research investigated the pharmacokinetic characteristics including plasma kinetics, tissue distribution, and plasma protein binding of platinum originating from dicycloplatin in rats and dogs in detail for the first time by ICP-MS.

Impact of long-term serum platinum concentrations on neuro- and ototoxicity in Cisplatin-treated survivors of testicular cancer

PURPOSE

Cisplatin-induced neurotoxicity and ototoxicity (NTX) are important adverse effects after chemotherapy for testicular cancer (TC). Although serum platinum is measurable years after therapy, its impact on NTX has not been evaluated.

PATIENTS AND METHODS

In all, 169 cisplatin-treated survivors of TC provided blood samples at Survey I and reported NTX during Survey I (1998-2002) and Survey II (2007-2008). Serum platinum was quantified by inductively coupled plasma mass spectrometry. Patient-reported outcomes were evaluated with the Scale for Chemotherapy-Induced Neurotoxicity (SCIN), regarding the extent of symptom bother as 0, "not at all"; 1, "a little"; 2, "quite a bit"; or 3, "very much." Summing the six symptom scores yielded a total SCIN score of 0 to 18. Categorizing total SCIN scores into quartiles yielded similar-sized groups with increasing symptoms. Multivariate ordinal logistic regression analyses evaluated associations between NTX and long-term serum platinum levels, adjusting for cisplatin dose, dosing schedule, and age.

RESULTS

At Survey I, a significant four- to five-fold association with total SCIN score emerged for the highest serum platinum quartile (odds ratio [OR], 4.69; 95% CI, 1.82 to 12.08). Paresthesias and Raynaud's syndrome (hands and feet) showed significant two- to four-fold increased risks with the highest platinum quartile. At Survey II, total SCIN score remained significantly associated with the highest platinum quartile (OR, 4.28; 95% CI, 1.36 to 13.48). Paresthesias (hands and feet) and tinnitus showed significant three- to four-fold increased risks for the highest platinum quartile. Cumulative cisplatin dose was not associated with total SCIN score or individual SCIN symptoms in multivariate analyses.

CONCLUSION

Here we document a significant relationship between increasing levels of residual serum platinum and NTX severity after adjusting for initial cisplatin dose.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

Long-term platinum retention after treatment with cisplatin and oxaliplatin

Background

The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.

Methods

45 patients, treated 8–75 months before participating in this study, were included. Platinum levels in plasma and plasma ultrafiltrate (pUF) were determined. In addition, the reactivity of platinum species in pUF was evaluated. Relationships between platinum retention and possible determinants were evaluated.

Results

Platinum plasma concentrations ranged between 142–2.99 × 10³ ng/L. Up to 24% of plasma platinum was recovered in pUF. No platinum-DNA adducts in peripheral blood mononuclear cells (PBMCs) could be detected. Ex vivo incubation of DNA with pUF of patients revealed that up to 10% of the reactivity of platinum species was retained. Protein binding proceeded during sample storage. Sodium thiosulfate (STS) appeared to release platinum from the plasma proteins. Platinum levels were related to time, dose, STS co-administration, and glomerular filtration rates (GFR).

Conclusion

Our data suggest that plasma platinum levels are related to time, age, dose, GFR, and STS use. Platinum in plasma, probably, represent platinum eliminated from regenerating tissue. Platinum species in pUF were partly present in a reactive form. The effects of the reactivity on long-term consequences of Pt-containing chemotherapy, however, remains to be established.

The application of inductively coupled plasma mass spectrometry in clinical pharmacological oncology research

Metal-based anticancer agents are frequently used in the treatment of a wide variety of cancer types. The monitoring of these anticancer agents in biological samples is important to understand their pharmacokinetics, pharmacodynamics, and metabolism. In addition, determination of metals originating from anticancer agents is relevant to assess occupational exposure of health care personnel working with these drugs. The high sensitivity of inductively coupled plasma mass spectrometry (ICP-MS) has resulted in an increased popularity of this technique for the analysis of metal-based anticancer drugs. In addition to the quantitative analysis of the metal of interest in a sample, ICP-MS can be used as an ultrasensitive metal selective detector in combination with speciation techniques such as liquid chromatography. In the current review we provide a systematic survey of publications describing the analysis of platinum- and ruthenium-containing anticancer agents using ICP-MS, focused on the determination of total metal concentrations and on the speciation of metal compounds in biological fluids, DNA- and protein-adducts, and environmental samples. We conclude that ICP-MS is a powerful tool for the quantitative analysis of metal-based anticancer agents from multiple sample sources.

Determination of ruthenium originating from the investigational anti-cancer drug NAMI-A in human plasma ultrafiltrate, plasma, and urine by inductively coupled plasma mass spectrometry

We present a highly sensitive, rapid method for the determination of ruthenium originating from the investigational anti-cancer drug NAMI-A in human plasma ultrafiltrate, plasma, and urine. The method is based on the quantification of ruthenium by inductively coupled plasma mass spectrometry and allows quantification of 30 ng L(-1) ruthenium in plasma ultrafiltrate and urine, and 75 ng L(-1) ruthenium in human plasma, in 150 microL of matrix. The sample pretreatment procedure is straightforward and only involves dilution with appropriate diluents. The performance of the method, in terms of accuracy and precision, fulfilled the most recent FDA guidelines for bioanalytical method validation. Validated ranges of quantification were 30.0 to 1 x 10(4) ng L(-1) for ruthenium in plasma ultrafiltrate and urine and 75.0 to 1 x 10(4) ng L(-1) for ruthenium in plasma. The applicability of the method and its superiority to atomic-absorption spectrometry were demonstrated in two patients who were treated with intravenous NAMI-A in a phase I trial. The assay is now successfully used to support pharmacokinetic studies in cancer patients treated with NAMI-A.