Ultrafilterable Platinum Research Articles

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.

Effect of Severe Renal Dysfunction on the Plasma Levels of DNA-Reactive Platinum after Oxaliplatin Administration.

Higher amounts of circulating ultrafilterable platinum (fPt) are found in patients with renal dysfunction receiving a constant dose of oxaliplatin. However, the increased systemic fPt levels do not increase oxaliplatin-induced toxicities. We hypothesized that renal dysfunction has minimal effect on the elimination rate of reactive fPt, and that the DNA-binding capacity is one of the properties of reactive Pt species. This study aimed to quantify DNA-reactive fPt in plasma and to evaluate the impact of severe renal dysfunction on its pharmacokinetics. The pharmacokinetics of oxaliplatin was assessed in rats with bilateral nephrectomy (BNx) and in a hemodialysis patient who received mFOLFOX7 therapy for advanced metastatic gastric cancer. The platinum concentrations were determined using inductively coupled plasma-mass spectrometry. The amount of DNA-reactive fPt in the plasma was evaluated by the reaction between plasma and calf thymus DNA. Compared to the sham group in rats, the BNx group had significantly higher plasma total fPt concentrations at 24 h after drug administration. However, there was no significant difference in the plasma levels of DNA-reactive fPt between the two groups. In a hemodialysis patient, the plasma levels of total fPt decreased to 35.9 and 7.3% at 2 and 14 d after treatment, respectively. The plasma level of DNA-reactive fPt also decreased to 1.9 and 0.6%, respectively, on these days. This study showed that severe renal dysfunction has a limited effect on the plasma levels of DNA-reactive fPt after oxaliplatin administration.

Intravenous lidocaine affects oxaliplatin pharmacokinetics in simultaneous infusion.

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 Cmax of oxaliplatin as a part of a larger study addressing the prevention and treatment of oxaliplatin induced peripheral neuropathy with lidocaine. In this prospective cross-over trial, patients received an oxaliplatin cycle with and without lidocaine (bolus 1.5 mgkg-1 followed by 1.5 mgkg-1h-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 Cmax of oxaliplatin (secondary). 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 Cmax 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. 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 Cmax in the chemotherapeutic cycle with lidocaine is significant and remarkable, but with an unknown exact mechanism or clinical significance, making further research desirable.

A pharmacokinetic analysis of cisplatin and 5-fluorouracil in a patient with esophageal cancer on peritoneal dialysis

Very little is known about the pharmacokinetics of chemotherapeutic agents in patients also being treated with continuous ambulatory peritoneal dialysis. We sought to evaluate the pharmacokinetics of cisplatin and 5-fluorouracil in plasma and peritoneal dialysate in a patient being treated for esophageal adenocarcinoma. A single patient with esophageal adenocarcinoma and on peritoneal dialysis for end-stage renal disease was treated with cisplatin 25mg/m(2) on day 1 of weeks 1 and 5 and continuous infusional 5-fluorouracil 1000mg/m(2)/day on days 1-4 of weeks 1 and 5 along with daily radiation therapy. Intense plasma and dialysate sampling was performed during the week 5 administration, followed by quantitation of platinum by atomic absorption spectrophotometry and 5-fluorouracil by LC-MS/MS. Following systemic administration, clearance of ultrafilterable (active) platinum over the first 6h was 20.8L/h, which is lower than previously reported clearance levels of ultrafilterable platinum. Total platinum AUC was 131μgh/mL, also higher than an AUC previously reported for total platinum in patients with normal renal function. Platinum-related material was detected in the peritoneal cavity, but this is likely inactive. 5-Fluorouracil penetrated the intraperitoneal cavity, but the contribution of peritoneal dialysis to drug clearance was negligible at 0.072%. Administration of intravenous cisplatin and 5-fluorouracil chemotherapy to a patient treated with continuous ambulatory peritoneal dialysis is feasible, but clearance in dialysate is nominal, thus suggesting that dose reduction is indicated for cisplatin. Systemic drug administration results in limited intraperitoneal penetration of 5-fluorouracil and inactive platinum species.

Plasma pharmacokinetics and tissue and brain distribution of cisplatin in musk shrews.

Cisplatin induces nausea and emesis, even with antiemetic supportive care. To assess platinum exposure, which could activate nausea and emesis, we quantitated platinum in the brain and various organs, and hindbrain and spinal cord substance P, a key neuropeptide for the neuronal signaling of nausea and emesis. Musk shrews, a model species for nausea and emesis research, were dosed intraperitoneally with 20 mg/kg cisplatin and euthanized at up to 72 h after injection. Concentrations of platinum were quantitated in plasma ultrafiltrate, plasma, lung, kidney, combined forebrain and midbrain, hindbrain, and spinal cord by flameless atomic absorption spectrometry. Hindbrains and spinal cords were analyzed for substance P by immunohistochemistry after injection of 20 or 30 mg/kg. Plasma ultrafilterable platinum concentrations decreased rapidly till 60 min after dosing and then more slowly by 24 h. The concentrations of total platinum in both the fore- and midbrain and the hindbrain were similar at all time points and were at least 20-fold lower than plasma total platinum concentrations. There were no significant changes in substance P immunoreactivity after cisplatin dosing. Histology revealed damage to the renal cortex by 72 h after injection of cisplatin. This is the first study to examine platinum concentrations in musk shrews after administration of cisplatin and delineate substance P immunohistochemical staining in the hindbrain and spinal cord of this species. The platinum concentrations detected in the brain could potentially contribute to the neurological side effects of cisplatin, such as nausea and emesis.

A phase I and pharmacokinetic study of oxaliplatin and bortezomib: activity, but dose-limiting neurotoxicity

The potential synergy of modulating platinum-induced DNA damage by combining the proteasome inhibitor bortezomib with oxaliplatin was studied in patients with solid tumors, with special attention to avoidance of cumulative neurotoxicity (NT). In a 3 + 3 dose escalation design, patients received bortezomib at 1.0-1.5 mg/m² on days 1 and 4 and oxaliplatin at 60-85 mg/m² on day 1 of a 14-day cycle. NT assessments were performed at the start of every two cycles. Oxaliplatin pharmacokinetics (PK) were determined pre- and post-bortezomib. Thirty patients were enrolled with 25 (11 men, 14 women) fully evaluable for NT assessments at cycle 2. The median age was 56 years (range 35-74 years); median number of cycles received 2 (range 1-10). At dose levels 2-5 (B 1.3 mg/m²), patients manifested NT grades 3 and 4 at a median 3.4 cycles (range 2-9 cycles): 3 had ataxia (one also with sensory neuropathy or neurogenic hypotension, respectively) and 3 had just sensory neuropathy. A 6th dose-level reducing bortezomib to 1.0 mg/m² with oxaliplatin 85 mg/m²) was explored and no NT or dose limiting toxicities were noted among 7 evaluable patients (5 receiving two or more cycles). Four patients experienced a partial response--one with platinum-resistant ovarian cancer, another with gastroesophageal cancer, another with ampulla of Vater carcinoma, and a patient with cholangiocarcinoma. PK studies at dose levels 1 and 2 showed greater mean ultrafiltrable platinum when oxaliplatin was dosed after bortezomib. Bortezomib 1.0 mg/m² × 2 every 14 days combines safely with oxaliplatin. At higher doses, cumulative NT (i.e., cerebellar signs and sensory neuropathy) occurs at an accelerated pace perhaps from a PK interaction.

Phase I trial and pharmacokinetic (PK) study of satraplatin in children and young adults with refractory solid tumors including brain tumors.

2554 Background: Satraplatin is an orally bioavailable platinum analog. Based on pre-clinical activity (IC500.02-8 µg/ml) including activity in cisplatin resistant cell lines, and clinical activity without neuro-, nephro-, or ototoxicity in adults with refractory tumors, we developed a phase 1 trial to determine the toxicities, maximum tolerated dose (MTD), and PKs of satraplatin in children with refractory solid tumors. Methods: Satraplatin (10 and 50 mg capsules) was administered orally once daily on days 1 - 5 of a 28 day cycle to cohorts of 3-6 patients (pts) at 60 mg/m2/dose (DL 1) and 80 mg/m2/dose (DL 2). Plasma ultrafiltrate (PUF) platinum was measured using atomic absorption spectroscopy during cycle 1 for PK analysis. Results: 9 pts [5 male, 4 female, median age 17 years (range 8-19)] with malignant glioma (n=4), ependymoma (n=2), medulloblastoma (n=1), osteosarcoma (n=1), or hepatoblastoma (n=1) received 1-10+ cycles (median 2). The MTD was exceeded at DL 2 as 2/4 pts had dose limiting toxicities (DLT) of delayed and prolonged myelosuppression (grade 3 thrombocytopenia, n=1; grade 3-4 neutropenia, n=2). 0/5 pts at DL 1 had DLTs. Grade 1 ototoxicity was seen in 1 pt at cycle 10. Non-DLTs included myelosuppression, gastrointestinal toxicities, fatigue, headache, liver enzyme elevation, and electrolyte abnormalities. No objective responses were observed, but 1 pt with gliomatosis cerebri has had radiographic stable disease through cycle 10+. Satraplatin mean exposure (AUC) and peak concentration (Cmax) were similar at both dose levels [day 1 PUF AUC0-24h 1.22 ± 0.55 µg/ml*h at DL1 (n=3), 1.02 ± 0.45 µg/ml*h at DL2 (n=3); Cmax0.17 ± 0.08 µg/ml at DL 1 (n=3), 0.16 ± 0.05 µg/ml at DL 2 (n=3)]. Terminal half-life was 14 ± 6 h and apparent clearance was 76 ± 29 L/h (n=6). Conclusions: The MTD of oral satraplatin in children with solid tumors is 60 mg/m2/dose daily x 5 q28 days. The toxicity profile was similar to adults, and delayed myelosuppression was DLT. Satraplatin exposure appears higher in pediatric pts compared to adults (PUF AUC0-24h 0.25-0.47 µg/ml*h at 60-80 mg/m2/dose). DL 1 will be expanded to gain additional experience regarding toxicities and PKs in a broader age range. Clinical trial information: NCT01259479.

Phase I study of the effects of renal impairment on the pharmacokinetics and safety of satraplatin in patients with refractory solid tumors

Satraplatin is an oral platinum analog with demonstrated activity in a range of malignancies. The current study was designed to evaluate the effect of varying degrees of renal impairment on the safety and pharmacokinetics (PKs) of satraplatin. Patients with advanced solid tumors, refractory to standard therapies, were eligible. The study included four cohorts of patients with varying levels of renal function, and eight patients per cohort: Group 1 (G1) = normal renal function; G2 = mild renal impairment [creatinine clearance (CrCl) 50-80 ml/min]; G3 = moderate impairment (CrCl 30 to <50 ml/min); G4 = severe impairment (CrCl <30 ml/min). Satraplatin was administered orally at 80 mg/m(2)/day on days 1-5 every 35 days. A total of 32 patients were enrolled, 8 patients in each renal function group. Each group tolerated the dose of 80 mg/m(2)/day on days 1-5 every 35 days without the need for dose deescalation. The most common adverse events were fatigue (63%), nausea (56%), diarrhea (53%), anorexia (47%), constipation (38%), vomiting (28%), anemia, dyspnea, and thrombocytopenia (25%). There were no dose-limiting toxic effects in any study group. There was increased exposure to plasma platinum and plasma ultrafiltrate platinum in patients with moderate to severe renal impairment. Satraplatin PKs was altered in patients with renal impairment. However, a corresponding increase in satraplatin-related toxic effects was not observed.

Pharmacokinetics of miriplatin in experimental dog models of hepatic or renal impairment

Miriplatin is an anticancer platinum complex for treatment of hepatocellular carcinomas by intra-hepatic arterial injection suspended in an iodinated ethyl ester of fatty acids from poppy seed oil as a carrier. Effects of liver and kidney function on( 14)C-miriplatin pharmacokinetics were assessed using dog models of hepatic and renal impairment introduced by thioacetamide exposure and 7/8 nephrectomy, respectively. Miriplatin was selectively delivered to the liver; platinum and radioactive component were gradually released into systemic circulation and excreted into urine. Microautoradiographic analysis of liver specimens showed( 14)C-miriplatin to be localized in blood vessels and/or macrophage-like cells. These features of miriplatin disposition were not affected by hepatic impairment. Thus, in clinical settings, hepatic impairment would not be expected to affect the intra-hepatic distribution and systemic pharmacokinetics of miriplatin. In dogs with renal impairment, although inconclusive, plasma concentrations of ultrafilterable platinum and radioactivity increased due to reduction in renal clearance.

A Phase I clinical study of cisplatin-incorporated polymeric micelles (NC-6004) in patients with solid tumours

Background:On the basis of preclinical studies of NC-6004, a cisplatin-incorporated micellar formulation, we hypothesised that NC-6004 could show lower toxicity than cisplatin and show greater anti-tumour activity in phase I study.Methods:A total of 17 patients were recruited in a range of advanced solid tumour types. NC-6004 was administered intravenously (i.v.) every 3 weeks. The dose escalation started at 10 mg m−2 and was increased up to 120 mg m−2 according to the accelerated titration method and modified Fibonacci method.Results:One dose-limiting toxicity (DLT) occurred in a patient who was given 90 mg m−2 of NC-6004, otherwise any significant cisplatin-related toxicity was not observed or generally mild toxicity was observed. Despite the implementation of post-hydration and pre-medication regimen, renal impairment and hypersensitivity reactions still developed at 120 mg m−2, which led to the conclusion that the maximum tolerated dose was 120 mg m−2, and the recommended dose was 90 mg m−2, although DLT was not defined as per protocol. Stable disease was observed in seven patients. The maximum concentration and area under the concentration–time curve of ultrafilterable platinum at 120 mg m−2 NC-6004 were 34-fold smaller and 8.5-fold larger, respectively, than those for cisplatin.Conclusion:The delayed and sustained release of cisplatin after i.v. administration contributes to the low toxicity of NC-6004.

A phase I trial combining oral cisplatin (CP Ethypharm) with radiotherapy in patients with locally advanced head and neck squamous cell carcinoma

Purpose To determine the maximum tolerated dose (MTD) of oral cisplatin (CP Ethypharm®) in combination with radiotherapy in head and neck squamous cell carcinoma (HNSCC) and the recommended dose for phase II trials. Patients and methods Phase I, multicenter, open-labelled, non-comparative and dose escalating trial. CP Ethypharm® was administered on five consecutive days every other week for 7 weeks (4 treatment cycles) in combination with radiotherapy. Eighteen patients with locally advanced HNSCC were allocated to four cisplatin dose levels: 10 mg/m 2/day: 4 patients; 15 mg/m 2/day: 4, 20 mg/m 2/day: 5 and 25 mg/m 2/day: 5. The inclusion of patients was dictated by occurrence of dose limiting toxicities (DLTs) at each dosing level. Results The most frequently experienced AEs were gastrointestinal (GI) disorders. Five DLTs were observed, including three at 25 mg/m 2 level (two grade 2 renal toxicities, one grade 3 GI and renal toxicities), one at 20 mg/m 2 level (grade 3 GI disorders), one at 10 mg/m 2 level (grade 4 mucositis). PK analysis showed no significant difference of C max values between day 1 and day 5 of treatment at each dose level (total & ultrafilterable platinum). Conclusion Due to 3 DLTs experienced at 25 mg/m 2/day, MTD was reached and the recommended dose for phase II studies was determined as 20 mg/m 2/day.

A comparative study of pharmacokinetics, urinary excretion and tissue distribution of platinum in rats following a single-dose oral administration of two platinum(IV) complexes LA-12 (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) and satraplatin (OC-6-43)-bis(acetato)amminedichloro(cyclohexylamine)platinum(IV)

This study compared the pharmacokinetics, tissue distribution, and urinary excretion of platinum in rats after single oral doses of LA-12 and satraplatin. Both platinum derivatives were administered to male Wistar rats as suspensions in methylcellulose at four equimolar doses within the range of 37.5-300 mg LA-12/kg body weight. Blood sampling was performed until 72 h, and plasma and plasma ultrafiltrate were separated. Moreover, urine was collected until 72 h, and kidney and liver tissue samples were obtained at several times after administration. Platinum was measured by atomic absorption spectrometry. The pharmacokinetics of platinum was analyzed by population modelling and post hoc Bayesian estimation as well as using non-compartmental pharmacokinetic analysis of the mean concentration-time curves. Platinum was detected in all plasma and ultrafiltrate samples 15 min after oral administration of both compounds and peaked between 3-4 h and 1-3 h, respectively. Similar for LA-12 and satraplatin, the C (max) and AUC values of plasma and ultrafiltrate platinum increased less than in proportion to dose. The mean C (max) and AUC values of plasma platinum observed after administration of LA-12 were from 0.84 to 2.5 mg/l and from 20.2 to 75.9 mg h/l. For ultrafiltrate platinum, the corresponding ranges were 0.16-0.78 mg/l and 0.63-1.8 mg h/l, respectively. The AUC of plasma platinum was higher after satraplatin (P < 0.001). However, administration of LA-12 resulted in significantly higher AUC values of ultrafiltrate platinum after the doses of 150 mg and 300 mg/kg (P < 0.01), respectively, and the C (max) values were significantly higher starting from the dose of 75 mg/kg LA-12 and upward (P < 0.01). Cumulative 72-h urinary recovery of platinum dose was below 5% for both compounds, and it decreased with the dose of satraplatin (P < 0.01), while a numerical decrease was observed after administration of LA-12 that did not reach statistical significance (P = 0.41). The renal clearance of free platinum was similar regardless of the dose and compound administered. Platinum concentrations in the liver homogenate exceeded those in the kidney. Distribution of platinum to tissues was higher after LA-12 compared to satraplatin. The difference in kidney platinum increased with dose and was twofold after 350 mg/kg LA-12. Liver platinum was twofold higher after LA-12 across all four doses. In conclusion, this first comparative pharmacokinetic study with LA-12 and satraplatin shows that characteristics of platinum exposure evaluated in the plasma, plasma ultrafiltrate and kidney and liver tissues increase less than in proportion to dose following a single-dose administration of 37.5-300 mg/kg to Wistar rats. These findings together with the dose-related elevation in the pharmacokinetic characteristics V/F and CL/F of platinum and ultrafiltrate platinum as well as a drop in platinum urinary recovery are consistent with a dose-related decrease in the extent of oral bioavailability most likely due to saturable intestinal absorption.

A phase II trial and pharmacokinetic study of oxaliplatin in children with refractory solid tumors: A Children's Oncology Group study

Platinating agents are used in the treatment of a spectrum of childhood cancers. Oxaliplatin, a third generation platinum compound, may provide less toxicity and be more effective. A phase 2 study was performed to estimate the response rate to single agent oxaliplatin in patients with refractory pediatric solid tumors, and to further describe the toxicities and pharmacokinetics of the drug in this population. Subjects, < or =21 years of age at original diagnosis, received oxaliplatin (130 mg/m(2)) intravenously every 21 days. Prior platinum exposure was acceptable. Histologies included: Ewing sarcoma/peripheral PNET, osteosarcoma, rhabdomyosarcoma, neuroblastoma, high and low grade astrocytoma, brain stem glioma, ependymoma, hepatoblastoma and selected rare tumors. A two-stage design, enrolling 10 + 10 subjects, was used for each disease stratum. Limited sampling pharmacokinetic studies were performed. Of 124 eligible subjects (75 males), 113 were evaluable for response and 69 (62%) had received platinum previously. Only one objective response was observed, a partial response in a 6-year-old child with ependymoma. An additional 13 subjects with various other solid tumors had stable disease, receiving a median (range) of 13.5 (2-17) cycles. Five subjects completed 17 treatment cycles. Thrombocytopenia was the most common toxicity observed. The median (range) terminal half-life and clearance for ultrafiltrable platinum were 293 (187-662 hr) and 14.0 (1.9-24.9 L/hr/m(2)), respectively (n = 49). Although reasonably well tolerated, oxaliplatin administered as a single agent has limited activity in pediatric patients with relapsed or refractory solid tumors.

Pharmacokinetics (PK) of oxaliplatin (OX) after intraperitoneal (IP) and intravenous (IV) administration in patients with gynecological malignancies.

2584 Background: Combined IV/IP chemotherapy has been associated with improved survival in ovarian cancer patients. Cisplatin is the most common drug used IP but is associated with significant toxicity. OX is a significantly larger molecule and may therefore have improved IP PK as compared to cisplatin IP. We evaluated the PK disposition of IP and IV OX as part of a phase I study. Methods: A phase I study with 2 arms was performed using modified Fibonacci dose escalation in patients (pts) with intraperitoneal ovarian cancer. In arm 1, pts received docetaxel (Doc) 75 mg/m2 IV on day 1 and OX 50 mg/m2 IP (dose level [DL] 1; n = 3) or OX 75 mg/m2 IP (DL2; n = 6) on day 2. In arm 2, pts received OX 75 mg/m2 IV on day 1 and Doc 50 mg/m2 IP (DL1; n = 3) or Doc 75 mg/m2 IP (DL2; n = 1) on day 2. IP fluid and plasma was collected at 0-24 h, 48 h, and 72 h after OX IP. Plasma was collected at 0-24 h after OX IV. Total and ultrafiltrate (UF) platinum (Pt) were measured in plasma and IP fluid via inductively coupled plasma mass spectrometry (ICP-MS). Area under the concentration versus time curve (AUC) and maximum concentration (Cmax) were estimated. Results: The PK of OX IP at 50 mg/m2 and 75 mg/m2 were similar and thus combined in the Table. Conclusions: Total and UF Pt were approximately 1.9- and 10.8-fold higher, respectively, in IP fluid compared with plasma after OX IP. The plasma exposure of UF Pt was approximately 1.5- to 2-fold lower after OX IP as compared with OX IV. The intraperitoneal tumor site has a higher exposure of the active unbound Pt with less systemic exposure following OX IP compared with OX IV. The PK properties of OX IP appear to be superior to OX IV and potentially cisplatin IP. Units IP Plasma Ratio IP:Plasma Arm 1 OX IP (n=9) Total Pt (mean ± SD) UF Pt (mean ± SD) Total Pt (mean ± SD) UF Pt (mean ± SD) Total Pt (mean ± SD) UF Pt (mean ± SD) AUC0–72h μg/mL·h 88.5 ± 58.5 50.9 ± 35.8 46.3 ± 10.6 4.7 ± 1.5 1.9 10.8 AUC0–24h μg/mL·h 60.5 ± 39.4 47.6 ± 34.4 21.1 ± 7.3 3.1 ± 1.0 2.9 15.4 Cmax μg/mL 11.1 ± 5.9 11.8 ± 7.6 1.2 ± 0.6 0.2 ± 0.05 9.4 65.9 Arm 2 OX IV (n=4) AUC0–24h μ g/mL·h — — 32.4 ± 12.3 5.7 ± 3.1 — — Cmax μ g/mL — — 7.0 ± 9.2 1.7 ± 2.6 — — Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration sanofi-aventis

In Vitro Circuit Stability of 5-Fluorouracil and Oxaliplatin in Support of Hyperthermic Isolated Hepatic Perfusion

Over the years, a large number of drugs have been used in isolated perfusion of extremities or organs. To interpret the pharmacokinetics of these drugs correctly, the contributions of tissue or organ clearance and chemical degradation, respectively, to overall drug elimination from the circuit need to be identified. In support of a phase I clinical trial of isolated hepatic perfusion (IHP), delivering 5-fluorouracil (5-FU) and oxaliplatin to patients with colorectal cancer hepatic metastases, we aimed to characterize the stability of 5-FU and oxaliplatin in the IHP circuit. Stability of 5-FU and oxaliplatin was assessed in human blood, lactated Ringer infusion (LRI), and in an in vitro IHP circuit consisting of both blood and LRI. Samples were analyzed with liquid chromatography tandem mass spectrometry (5-FU) and atomic absorption spectrophotometry (oxaliplatin). 5-FU was stable under all tested in vitro conditions, but ultrafilterable platinum concentrations decreased slowly with a half-life of 85 minutes in both IHP perfusate and whole blood. The stability of 5-FU in the media containing blood is likely attributable to saturation of dihydropyrimidine dehydrogenase. The decrease of ultrafilterable platinum in blood-containing media with an 85 minutes half-life is in agreement with previous reports on oxaliplatin biotransformation. Oxaliplatin and 5-FU are sufficiently stable in the circuit for the 1-hour perfusion in ongoing and planned clinical trials.

Drug Monitoring During FOLFOX6 Therapy in a Rectal Cancer Patient on Chronic Hemodialysis

Long-term hemodialysis is considered to be a significant risk factor for cancer, but little is known about the use of oxaliplatin in patients on chronic hemodialysis. A 58-year-old man on chronic hemodialysis was treated for unresectable rectal cancer with synchronous hepatic metastasis by FOLFOX6 therapy with therapeutic drug monitoring. Plasma levels of total platinum, ultrafiltrate (free) platinum and 5-fluorouracil were monitored from the start of oxaliplatin administration to 120 h after the end of oxaliplatin infusion. Pharmacokinetic data of free platinum showed a bimodal pattern, decreased rapidly during the first dialysis and subsequently rose until 48 h after oxaliplatin infusion. The free platinum area under the curve was 15.7-18.9 microg h/ml when 40 mg/m(2) of oxaliplatin was administered, which was comparable to the area under the curve at 85 mg/m(2) in patient with normal renal function. The total platinum level reached a peak immediately before dialysis and gradually decreased. The 5-fluorouracil level decreased rapidly after the start of dialysis and remained constant during the continuous infusion of 5-fluorouracil. Tumor response was judged to be stable disease for >6 months, and no peripheral neuropathy or other toxicity was observed even after 11 courses. FOLFOX6 therapy with reduced dose of oxaliplatin had been safely performed for >6 months without any severe toxicity. The serum levels of free platinum showed bimodal pattern, and this second peak increased the area under the curve of free platinum. This pattern seems to be unique in patients on hemodialysis.

Satraplatin, an Oral Platinum, Administered on a Five-day Every-Five-Week Schedule: a Pharmacokinetic and Food Effect Study

The study aimed to assess the pharmacokinetic behavior of satraplatin under fasted and fed conditions, and its safety and preliminary antitumor activity in adults with advanced solid tumors. Satraplatin was administered orally at 80 mg/m(2) once daily with prophylactic antiemetics for 5 consecutive days every 5 weeks. Patients were randomized to receive day 1 and day 5 doses of satraplatin in either the fed or fasted state, the order being reversed for cycle 2. Pharmacokinetic sampling was done during the first two cycles. For all subsequent cycles, patients received satraplatin in the fasted state. Seventeen patients were treated with 60 total cycles of satraplatin. There was no dose-limiting toxicity during cycle 1. Severe hematologic toxicity was rare and the hematologic nadir occurred during week 4. Nausea, vomiting, and diarrhea were grade 1/2. No significant cardiac, renal, hepatic, or neurologic toxicity was observed. The hypothesis that food decreased ultrafiltrate platinum bioavailability could not be rejected, as the lower limit of the 90% confidence intervals for peak plasma concentration and area under the concentration-time curve from time 0 to 24 hours were 56.14% and 73.53%, respectively, both below the 80% bioequivalence acceptance criterion. One partial response (hormone refractory prostate cancer) and four durable stable diseases (breast, ovarian, parotid, and hormone refractory prostate cancer) were confirmed. There is an effect of food on the pharmacokinetics of satraplatin, the clinical significance of which is unclear. It is recommended that satraplatin be administered in the fasting state. This 5-week interval schedule of satraplatin was well tolerated in heavily pretreated patients.

Phase 1 and pharmacokinetic study of concurrent carboplatin and irinotecan in subjects aged 1 to 21 years with refractory solid tumors

Preclinical testing suggests the combination of carboplatin and irinotecan has at least additive antitumor activity. The primary objectives of the current study were to determine the maximum tolerated doses (MTDs) and recommended phase 2 doses of carboplatin administered with irinotecan to pediatric patients with refractory solid tumors. This was a multicenter, open-label, single-arm dose escalation study in which subjects with refractory solid tumors received 21-day treatment cycles of intravenous carboplatin on Day 1 followed by intravenous irinotecan administered daily for 10 days within 2 consecutive weeks. The plasma pharmacokinetics of ultrafiltrable platinum, irinotecan, and 2 irinotecan metabolites were determined during Cycle 1. The interpatient plan for dose escalation at study initiation was to increase irinotecan first followed by increases in carboplatin. Twenty-eight patients with a median age of 8.5 years (range, 1-21 years) were enrolled with a variety of solid tumors. Two of 6 subjects at the first dose level (carboplatin target area under the curve [AUC], 4.0 mg/mL*min; irinotecan, 18 mg/m2/dose) experienced dose-limiting gastrointestinal toxicities requiring a dose de-escalation scheme (carboplatin AUC, 4.0 mg/mL*min; irinotecan, 15 mg/m2/dose). Three of 6 subjects at the second dose level experienced dose-limiting gastrointestinal complications and bone marrow suppression. A further dose de-escalation to carboplatin AUC of 4.0 mg/mL*min and irinotecan of 12 mg/m2/dose resulted in dose-limiting bone marrow suppression in 1 of 13 patients treated at that dose, and therefore was determined to be the MTD. One complete response (in a patient with medulloblastoma) and 3 partial responses (in patients with neuroblastoma, medulloblastoma, and lymphoendothelial carcinoma, respectively) were observed. The recommended phase 2 dose in heavily pretreated pediatric patients is carboplatin (AUC, 4 mg/mL*min on Day 1) and irinotecan (12 mg/m2/dayx10 days) given every 21 days.

A Phase I Study of Hyperthermic Isolated Hepatic Perfusion with Oxaliplatin in the Treatment of Unresectable Liver Metastases from Colorectal Cancer

Isolated hepatic perfusion (IHP) is a proven approach for regional delivery of chemotherapy in patients with unresectable primary and metastatic tumors of the liver. Most trials of IHP have utilized melphalan as the active drug in the perfusate. We performed a phase I trial to evaluate the efficacy, safety, and maximum tolerated dose (MTD) of oxaliplatin delivered by hyperthermic isolated hepatic perfusion. A phase I dose-escalation trial of hyperthermic IHP with oxaliplatin in patients with unresectable metastatic colorectal cancer scheduled to undergo placement of a hepatic arterial infusion (HAI) pump was carried out. Thirteen patients were enrolled between November 2003 and September 2006. Dose-limiting veno-occlusive disease was observed at 60 mg/m(2). At the MTD of 40 mg/m(2) only minor transient liver dysfunction was observed. Ultrafilterable platinum area under the curve and maximum concentration delivered by IHP increased nonlinearly with dose as did platinum concentrations in liver biopsies obtained at the end of the 60 min IHP. Seventy-seven percent of patients had a >50% decrease in serum carcinoembryonic antigen (CEA) after IHP. The overall response rate to the combined IHP and HAI therapy was 66%. One patient had a durable complete response (>4 years). We conclude that hyperthermic IHP with oxaliplatin was safe and feasible at a dose of 40 mg/m(2). The ability to obtain complete vascular isolation with open IHP was confirmed. The response rate in this small phase I study was encouraging.

A Phase I and Pharmacokinetic Study of Weekly Oxaliplatin Followed by Paclitaxel in Patients with Solid Tumors

Oxaliplatin and paclitaxel are widely used in treating solid tumors. We designed a phase I study with the purpose of determining the maximal tolerated dose and pharmacokinetic properties of weekly oxaliplatin followed by paclitaxel based on evidence suggesting that weekly administration of both drugs allows equivalent dose intensity with less neurotoxicity. Twenty-three patients with advanced solid tumors were treated. Starting doses were 35 mg/m2 oxaliplatin followed by 45 mg/m2 paclitaxel weekly for 4 weeks every 6 weeks. Dose was escalated as follows: 45 mg/m2 oxaliplatin and 45 mg/m2 paclitaxel, 60 mg/m2 oxaliplatin and 45 mg/m2 paclitaxel, and 60 mg/m2 oxaliplatin and 60 mg/m2 paclitaxel. Pharmacokinetic studies were evaluated during the first course of therapy for oxaliplatin using population kinetics approach. A total of 49 courses were administered. The dose-limiting toxicity was peripheral neuropathy with oxaliplatin and paclitaxel both at 60 mg/m2. There were three partial responses. There was evidence of pharmacokinetic interaction with a significant amount of total platinum (46.2-49.5%/24 h) eliminated in the urine in this group of patients, consistent with published data from others. The total body clearance values of plasma platinum and ultrafiltrable platinum were higher in this combination compared with corresponding values from our previous study with oxaliplatin only (P < 0.001). The recommended phase II dose of this combination is 60 mg/m2 oxaliplatin followed by 45 mg/m2 paclitaxel. Evidence of antitumor activity and acceptable toxicity with this combination and schedule warrants further investigation. We have obtained more definitive pharmacokinetic properties of oxaliplatin and confirmed its drug interaction with paclitaxel in the current sequence.