Martin A. Graham

Dose-Escalating and Pharmacological Study of Oxaliplatin in Adult Cancer Patients With Impaired Renal Function: A National Cancer Institute Organ Dysfunction Working Group Study

PURPOSE This study was undertaken to determine the toxicities, pharmacokinetics, and maximum tolerated doses of oxaliplatin in patients with renal impairment and to develop formal guidelines for oxaliplatin dosing in this patient population. PATIENTS AND METHODS Thirty-seven adult cancer patients with variable renal function received intravenous oxaliplatin at 60 to 130 mg/m2 every 3 weeks. Patients were stratified by 24-hour creatinine clearance (CrCL) into four cohorts: group A (controls, CrCL > or =60 mL/min), group B (mild dysfunction, CrCL 40 to 59 mL/min), group C (moderate dysfunction, CrCL 20 to 39 mL/min), and group D (severe dysfunction, CrCL <20 mL/min). Doses were escalated in cohorts of three patients, and urine and plasma ultrafiltrates were assayed for platinum concentrations. RESULTS No dose-limiting toxicities were observed in any patient group during the first cycle of therapy. Escalation of oxaliplatin to the maximum dose of 130 mg/m2 was well tolerated in all patient groups with a CrCL > or =20 mL/min (groups A, B, and C). Pharmacokinetic analysis showed that patients with decreased CrCL had a corresponding decrease in the clearance of plasma ultrafiltrable platinum (r2 = 0.765). However, oxaliplatin-induced side effects were not more common or severe in patients with mild to moderate renal dysfunction, despite the decrease in ultrafiltrable platinum clearance. CONCLUSION Oxaliplatin at 130 mg/m2 every 3 weeks is well tolerated by patients with mild to moderate degrees of renal dysfunction. These data strongly support the recommendation that dose reductions of single-agent oxaliplatin are not necessary in patients with a CrCL greater than 20 mL/min.

Validation of a highly sensitive ICP-MS method for the determination of platinum in biofluids : application to clinical pharmacokinetic studies with oxaliplatin

ELOXATIN (Oxaliplatin) is a novel platinum containing anti-cancer agent with a diaminocyclohexane carrier ligand which has been approved in several major European countries. Clinical studies have demonstrated that the compound exhibits marked activity against colorectal cancers in combination with 5-fluorouracil (5-FU). The aim of this work was to develop and validate a highly sensitive inductively coupled plasma mass spectrometry assay for the determination of oxaliplatin-derived platinum in plasma ultrafiltrate, plasma and whole blood and to apply this technique to clinical pharmacokinetic studies with oxaliplatin. Ultratrace detection of platinum in plasma ultrafiltrate was achieved using ultrasonic nebulisation combined with ICP-MS. This technique allows detection of platinum at the 0.001 microg Pt/ml level in only 100 microl of matrix. Assays in blood and plasma utilised a standard Meinhardt nebuliser and spray chamber, achieving detection limits of 0.1 microg Pt/ml in 100 and 200 microl of matrix, respectively. The assays were validated (accuracy and precision within +/- 15%) over the concentration ranges: 0.001-0.250 microg Pt/ml in plasma ultrafiltrate and 0.1-10 microg Pt/ml for plasma and whole blood. The effect of sample digestion. dilution, long term frozen storage and quantitation in the presence of 5-FU were also investigated and validated. The method was used to monitor platinum exposure following oxaliplatin administration (130 mg/m2) to cancer patients. Following a 2 h i.v. infusion, peak platinum levels declined in a triphasic manner in all blood compartments. Free platinum was detected in plasma ultrafiltrate at low levels (0.001 0.010 microg Pt/ml) for up to 3 weeks. In conclusion, a highly sensitive and specific assay has been developed for the determination of platinum in biofluids. This method enabled characterisation of the long term exposure to platinum in patients following oxaliplatin treatment.

Birinapant (TL32711), a Bivalent SMAC Mimetic, Targets TRAF2-Associated cIAPs, Abrogates TNF-Induced NF-κB Activation, and Is Active in Patient-Derived Xenograft Models

The acquisition of apoptosis resistance is a fundamental event in cancer development. Among the mechanisms used by cancer cells to evade apoptosis is the dysregulation of inhibitor of apoptosis (IAP) proteins. The activity of the IAPs is regulated by endogenous IAP antagonists such as SMAC (also termed DIABLO). Antagonism of IAP proteins by SMAC occurs via binding of the N-terminal tetrapeptide (AVPI) of SMAC to selected BIR domains of the IAPs. Small molecule compounds that mimic the AVPI motif of SMAC have been designed to overcome IAP-mediated apoptosis resistance of cancer cells. Here, we report the preclinical characterization of birinapant (TL32711), a bivalent SMAC-mimetic compound currently in clinical trials for the treatment of cancer. Birinapant bound to the BIR3 domains of cIAP1, cIAP2, XIAP, and the BIR domain of ML-IAP in vitro and induced the autoubiquitylation and proteasomal degradation of cIAP1 and cIAP2 in intact cells, which resulted in formation of a RIPK1:caspase-8 complex, caspase-8 activation, and induction of tumor cell death. Birinapant preferentially targeted the TRAF2-associated cIAP1 and cIAP2 with subsequent inhibition of TNF-induced NF-κB activation. The activity of a variety of chemotherapeutic cancer drugs was potentiated by birinapant both in a TNF-dependent or TNF-independent manner. Tumor growth in multiple primary patient–derived xenotransplant models was inhibited by birinapant at well-tolerated doses. These results support the therapeutic combination of birinapant with multiple chemotherapies, in particular, those therapies that can induce TNF secretion. Mol Cancer Ther; 13(4); 867–79. ©2014 AACR.

Oxaliplatin Pharmacokinetics and Pharmacodynamics in Adult Cancer Patients with Impaired Renal Function

Purpose: To characterize the pharmacokinetics and pharmacodynamics of oxaliplatin in cancer patients with impaired renal function. Experimental Design: Thirty-four patients were stratified by 24-h urinary creatinine clearance (CrCL) into four renal dysfunction groups: group A (control, CrCL, ≥60 mL/min), B (mild, CrCL, 40-59 mL/min), C (moderate, CrCL, 20-39 mL/min), and D (severe, CrCL, <20 mL/min). Patients were treated with 60 to 130 mg/m2 oxaliplatin infused over 2 h every 3 weeks. Pharmacokinetic monitoring of platinum in plasma, plasma ultrafiltrates, and urine was done during cycles 1 and 2. Results: Plasma ultrafiltrate platinum clearance strongly correlated with CrCL (r2 = 0.712). Platinum elimination from plasma was triphasic, and maximal platinum concentrations (Cmax) were consistent across all renal impairment groups. However, only the β-half-life was significantly prolonged by renal impairment, with values of 14.0 ± 4.3, 20.3 ± 17.7, 29.2 ± 29.6, and 68.1 h in groups A, B, C, and D, respectively (P = 0.002). At a dose level of 130 mg/m2, the area under the concentration time curve increased in with the degree of renal impairment, with values of 16.4 ± 5.03, 39.7 ± 11.5, and 44.6 ± 14.6 μg·h/mL, in groups A, B, and C, respectively. However, there was no increase in pharmacodynamic drug-related toxicities. Estimated CrCL using the Cockcroft-Gault method approximated the measured 24-h urinary CrCL (mean prediction error, −5.0 mL/min). Conclusions: Oxaliplatin pharmacokinetics are altered in patients with renal impairment, but a corresponding increase in oxaliplatin-related toxicities is not observed.

Oxaliplatin: A Review of Evolving Concepts

Department of Oncology, Weiler Hospital/Montefiore Medical Center and the Albert Einstein Cancer Center of the Albert Einstein College of Medicine, Room 2S-63, 1825 Eastchester Road, Bronx, NY 10461 Department of Clinical Pharmacokinetics and Drug Metabolism, Sanofi-Synthelabo, 9 Great Valley Parkway, Malvern, Pennsylvania Department of Pathology, Albert Einstein College of Medicine, Bronx, New York Cancer Therapy Evaluation Program of the National Cancer Institute, Bethesda, Maryland Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Dose-Escalating and Pharmacologic Study of Oxaliplatin in Adult Cancer Patients with Impaired Hepatic Function: A National Cancer Institute Organ Dysfunction Working Group Study

Purpose: To determine the toxicities, pharmacokinetics, and maximally tolerated doses of oxaliplatin in patients with hepatic impairment and to develop formal guidelines for oxaliplatin dosing in this patient population. Experimental Design: Sixty adult cancer patients with variable hepatic function received i.v. oxaliplatin ranging from 60 to 130 mg/m2 every 3 weeks. Patients were stratified by levels of total bilirubin, aspartate aminotransferase (AST), and alkaline phosphatase (AP) into five cohorts based on the degree of hepatic dysfunction: control group A [bilirubin, AST, and AP ≤ upper limit of normal (ULN)], mild dysfunction group B (bilirubin ≤ ULN, ULN < AST ≤ 2.5 × ULN, or ULN < AP ≤ 5 × ULN), moderate dysfunction group C (ULN < bilirubin ≤ 3.0 mg/dL, AST > 2.5 × ULN, or AP > 5 × ULN), severe dysfunction group D (bilirubin > 3.0 mg/dL, any AST, and any AP), and liver transplantation group E (any bilirubin, any AST, and any AP). Doses were escalated in cohorts of three patients, and urine and plasma ultrafiltrates were assayed for platinum concentrations. Results: Dose escalation of single-agent oxaliplatin to 130 mg/m2 was well tolerated in all cohorts. Platinum clearance did not correlate with any liver function test. Two of 56 assessable patients with a diagnosis of laryngeal carcinoma and cervical adenocarcinoma experienced partial responses lasting 3 and 5.5 months. Conclusions: Oxaliplatin at 130 mg/m2 every 3 weeks was well tolerated in all patients with impaired liver function. Dose reductions of single-agent oxaliplatin are not indicated in patients with hepatic dysfunction.

Absence of Adverse Effects in Cynomolgus Macaques Treated with CNTO 95, a Fully Human Anti-αv Integrin Monoclonal Antibody, Despite Widespread Tissue Binding

Purpose: CNTO 95 is a fully human anti-αv integrin monoclonal antibody that inhibits macaque and rodent angiogenesis and inhibits human tumor growth in rodents. The purpose of these studies was to evaluate the preclinical safety of long-term administration of CNTO 95 in cynomolgus macaques. Experimental Design: The in vitro binding profiles of CNTO 95 to human and macaque tissues and the in vivo binding to macaque tissues was evaluated by immunohistochemistry. The preclinical safety of CNTO 95 (10 and 50 mg/kg, i.v.) was evaluated in macaques treated once per week for up to 6 months. Safety was evaluated by clinical observations, ophthalmic and physical examinations (including heart rate, blood pressure, and electrocardiogram), clinical pathology (including coagulation parameters), and comprehensive anatomic pathology. The effect of CNTO 95 (50 mg/kg, i.v.) on incisional wound healing was evaluated in macaques. Results: The tissue binding studies showed that CNTO 95 bound with mild to moderate intensity to macaque and human endothelial cells, epithelial cells, and vascular smooth muscle cells in most normal tissues examined. CNTO 95 showed strong to intense staining to the positive control tissue, human placenta. Despite the widespread binding to normal tissues, treatment of cynomolgus macaques with CNTO 95 produced no signs of toxicity and no histopathologic changes in any of the tissues examined (including ovaries and bone growth plates). CNTO 95 did not impair wound healing. Conclusion: These studies show that CNTO 95 is safe and, unlike some other angiogenesis inhibitors, does not seem to inhibit normal physiologic angiogenesis.

The effect of the anthrapyrazole antitumour agent CI941 on rat liver microsome and cytochrome P-450 reductase mediated free radical processes: inhibition of doxorubicin activation in vitro

The anthrapyrazole CI941 is one of a new series of DNA complexing drugs which displays high level broad spectrum antitumour activity in mice. In view of the proposed role of drug free radical formation, superoxide generation and lipid peroxidation in anthracycline and anthraquinone induced toxicities, the redox biochemistry of CI941 has been investigated. Studies have been performed in vitro using rat liver microsomes and purified cytochrome P-450 reductase. In addition, the ability of CI941 to undergo chemical reduction has been examined. Pulse radiolysis of CI941 demonstrated that the drug can undergo chemical reduction with a one electron reduction potential of E1(7) = -538 +/- 10 mV. However, electron spin resonance (ESR) spectroscopy studies using either NADPH fortified microsomes or cytochrome P-450 reductase, failed to detect a drug free radical signal. Unlike doxorubicin, CI941 (150 microM) inhibited basal rate microsomal NADPH consumption by 45%. Furthermore, CI941 (50-200 microM) antagonised doxorubicin stimulated (1.8-fold) NADPH oxidation by over 50%. CI941 also antagonised the formation of a doxorubicin free radical ESR signal in a concentration dependent manner. CI941 induced minimal superoxide generation in the presence of either microsomes or cytochrome P-450 reductase and inhibited doxorubicin induced (50 microM) superoxide formation by up to 80% (50-200 microM CI941). Importantly, CI941 inhibits both basal rate and doxorubicin (100 microM) stimulated lipid peroxidation (52% inhibition at 5 microM CI941). These data suggest that CI941 is unlikely to induce free radical mediated tissue damage in vivo. On the contrary, CI941 may have a protective role if used in combination with doxorubicin.

Phase I trial of tirapazamine in combination with cisplatin in a single dose every 3 weeks in patients with solid tumors.

PURPOSE AND METHODS Tirapazamine (SR4233, WIN 59075) is a benzotriazine-di-N-oxide bioreductive agent that is selectively activated to a reactive DNA-damaging species in hypoxic tumors. Preclinical studies show that synergistic antitumor activity results from a schedule-dependent interaction between tirapazamine and several cytotoxic drug classes, including cisplatin. In a phase I combination study, tirapazamine (130 to 260 mg/m2) was administered as a 1-hour intravenous (IV) infusion beginning 3 hours before cisplatin (75 to 100 mg/m2). Thirteen patients received 41 courses of therapy. These patients had an excellent performance status and were not heavily pretreated. The predominant diagnosis was lung cancer. RESULTS The major acute side effects were nausea and vomiting, which were controlled with an intensive antiemetic regimen. Other acute effects included diarrhea and muscle cramping, while with repeated dosing, anorexia and fatigue predominated. Full doses of each agent were well tolerated in combination, although in this previously treated population, fatigue increased markedly after three cycles of therapy. Partial responses were observed in two patients (one with non-small-cell lung cancer and one with breast cancer), and a minor response occurred in a patient with mesothelioma. Tirapazamine pharmacokinetics were linear with respect to increasing dose with a mean maximum plasma concentration (Cmax) of 5.97 +/- 2.25 microg/mL and an area under the concentration-time curve (AUC) of 811.4 +/- 311.9 microg/mL.min at 260 mg/m2. These results are consistent with other ongoing single-agent and combination studies and indicate that therapeutically relevant levels of tirapazamine are achievable in patients based on animal models. The mean cisplatin AUC was 285.6 +/- 46.4 microg/mL.min with mean Cmax values of 3.38 +/- 0.43 microg/mL at 75 mg/m2. The clearance of cisplatin was unaffected by coadministration with tirapazamine. CONCLUSION This trial shows that in previously treated patients, full doses of cisplatin are well tolerated with increasing doses of tirapazamine up to 260 mg/m2. The observation of clinical responses in this trial supports the phase II investigation of this regimen.

Temporal and Spatial Evolution of Therapy-Induced Tumor Apoptosis Detected by Caspase-3–Selective Molecular Imaging

Purpose: Induction of apoptosis in tumors is considered a desired goal of anticancer therapy. We investigated whether the dynamic temporal and spatial evolution of apoptosis in response to cytotoxic and mechanism-based therapeutics could be detected noninvasively by the caspase-3 radiotracer [18F]ICMT-11 and positron emission tomography (PET). Experimental Design: The effects of a single dose of the alkylating agent cyclophosphamide (CPA or 4-hydroperoxycyclophosphamide), or the mechanism-based small molecule SMAC mimetic birinapant on caspase-3 activation was assessed in vitro and by [18F]ICMT-11–PET in mice bearing 38C13 B-cell lymphoma, HCT116 colon carcinoma, or MDA-MB-231 breast adenocarcinoma tumors. Ex vivo analysis of caspase-3 was compared to the in vivo PET imaging data. Results: Drug treatment increased the mean [18F]ICMT-11 tumor uptake with a peak at 24 hours for CPA (40 mg/kg; AUC40–60: 8.04 ± 1.33 and 16.05 ± 3.35 %ID/mL × min at baseline and 24 hours, respectively) and 6 hours for birinapant (15 mg/kg; AUC40–60: 20.29 ± 0.82 and 31.07 ± 5.66 %ID/mL × min, at baseline and 6 hours, respectively). Voxel-based spatiotemporal analysis of tumor-intrinsic heterogeneity suggested that discrete pockets of caspase-3 activation could be detected by [18F]ICMT-11. Increased tumor [18F]ICMT-11 uptake was associated with caspase-3 activation measured ex vivo, and early radiotracer uptake predicted apoptosis, distinct from the glucose metabolism with [18F]fluorodeoxyglucose-PET, which depicted continuous loss of cell viability. Conclusion: The proapoptotic effects of CPA and birinapant resulted in a time-dependent increase in [18F]ICMT-11 uptake detected by PET. [18F]ICMT-11–PET holds promise as a noninvasive pharmacodynamic biomarker of caspase-3–associated apoptosis in tumors. Clin Cancer Res; 19(14); 3914–24. ©2013 AACR.