Comparative adverse effect profiles of platinum drugs

Late onset hearing loss: a significant complication of cancer survivors treated with Cisplatin containing chemotherapy regimens

Cisplatin is a known ototoxic agent and has been associated with late onset hearing loss (LOHL) in children beyond completion of treatment. We completed a retrospective review of 160 patients yielding 59 who received cisplatin and had sufficient data to determine the presence of LOHL. LOHL was defined as a significant change in hearing thresholds 6 months past the last cisplatin therapy. A significant change was defined as a decrease of >15 dB in a frequency from 1 to 8 kHz in either ear, or a decrease of 10 dB at 2 or more frequencies in the same ear, compared with the previously entered audiogram. Hearing loss was classified using the Brock grading system for each ear. Of the 59 patients evaluated, 51% exhibited LOHL. Univariate analysis indicated LOHL was significantly associated with age of diagnosis (P=0.031), diagnosis of medulloblastoma (P=0.035), hearing aids (P=0.010), and cranial radiation (P=0.044), particularly to the posterior fossa (P=0.023). Multivariate analysis revealed only radiation to the posterior fossa (P=0.02) and the use of hearing aids (P=0.01) were significantly associated with LOHL. LOHL is a significant complication in childhood cancer survivors who receive cisplatin. Long-term audiologic monitoring after therapy is needed to identify the affected patients.

Cisplatin overdose: toxicities and management

Cisplatin is one of the most widely used antineoplastic agents in the treatment of solid tumour and haematological malignancies, including cancers of the testes, ovary, bladder, head and neck, oesophagus, stomach and lung, as well as lymphoma and osteosarcoma. Its non-specific targeting commonly results in adverse effects and toxicities affecting the gastrointestinal, renal, neurological and haematological systems even when administered at standard doses. Since cisplatin-related toxicities are dose-dependent, these may be more pronounced in the setting of a cisplatin overdose, resulting in significant morbidity and/or mortality. The incidence of cisplatin overdoses is unknown; however, early-phase clinical trials utilizing high-dose cisplatin, and case reports in the overdose setting have characterized the clinical features associated with cisplatin overdoses, highlighting some therapeutic strategies for consideration. To date, no published guidelines exist for managing a cisplatin overdose. The major toxicities of a cisplatin overdose include nausea and vomiting, renal insufficiency, electrolyte abnormalities, myelosuppression, ototoxicity, peripheral neuropathy, hepatotoxicity and retinopathy. Diarrhoea, pancreatitis, seizures and respiratory failure have also been reported. No specific antidote for cisplatin exists. Key management principles and strategies to lessen toxicities include renoprotection and enhancing drug elimination with aggressive intravenous hydration with or without the use of an osmotic diuretic, and avoidance of nephrotoxic medications. Sodium thiosulfate and plasmapheresis, with or without haemodialysis support, should be strongly considered. Close monitoring of clinical and laboratory parameters, and institution of supportive therapies, including antiemetics and haematopoietic colony stimulating factor support, are warranted. Based on the current literature, experimental therapies such as amifostine, ditiocarb sodium (diethyldithiocarbamate), acetylcysteine, fosfomycin and colestipol are of limited clinical effectiveness and remain investigational. This review serves to highlight the clinical spectrum of toxicities resulting from a cisplatin overdose, to critically appraise the available literature and to present a suggested algorithmic approach for the initial management of a cisplatin overdose.

A novel intralymphatic nanocarrier delivery system for cisplatin therapy in breast cancer with improved tumor efficacy and lower systemic toxicity in vivo

BACKGROUND

A lymphatically delivered nanoconjugate of cisplatin was evaluated in an orthotopic mouse model of locoregionally metastatic breast cancer (LABC) to determine if it can overcome some of the limitations of standard cisplatin therapy such as high systemic toxicity.

METHODS

Human breast cancer cells (10(7) MDA-MB-468LN) were injected into the mammary fat pad of female nu/nu mice. Once tumor volume reached 50 mm(3), intravenous cisplatin or subcutaneous hyaluronan-cisplatin (HA-cisplatin) nanoconjugate was given 1/week x 3 weeks at 3.3 mg/kg (platinum basis).

RESULTS

Nanoconjugates colocalized with the tumors after subcutaneous peritumoral injection and showed improved efficacy to intravenous cisplatin. After 1 month, renal tubular hemorrhage and edema were more prevalent in the intravenous formulation compared with subcutaneous HA-cisplatin nanoconjugates.

CONCLUSIONS

This nanocarrier delivery platform focuses on delivering drugs to the areas in which tumor burden is greatest, potentially reducing systemic toxicity, and has future applicability as a neoadjuvant or adjuvant therapy for LABC.

Cisplatin ototoxicity and protection: clinical and experimental studies

Cisplatin is a chemotherapeutic agent that is widely used to treat a variety of malignant tumors. Serious dose-limiting side effects like ototoxicity, nephrotoxicity and neurotoxicity occur with the use of this agent. This review summarizes recent important clinical and experimental investigations of cisplatin ototoxicity. It also discusses the utility of protective agents employed in patients and in experimental animals. The future strategies for limiting cisplatin ototoxicity will need to avoid interference with the therapeutic effect of cisplatin in order to enhance the quality of life of patients receiving this important anti-tumor agent.

Urinary excretion of carnitine as a marker of proximal tubular damage associated with platin-based antineoplastic drugs

BACKGROUND

Patients treated with cisplatin or carboplatin show increased renal excretion of carnitine. It is currently unclear whether this is also the case for oxaliplatin and which are the responsible mechanisms.

METHODS

We investigated 22 patients treated either with a single dose of cisplatin, carboplatin or oxaliplatin. Carnitine and kidney function parameters were determined in plasma and urine. Inhibition and mRNA expression of OCTN2, the principle carnitine transporter, were assessed in L6 cells overexpressing OCTN2 and in 293-EBNA cells, respectively.

RESULTS

Renal excretion of free and short-chain acylcarnitine increased already at the day of administration was maximal the day after and had normalized 1 week after administration of cisplatin, carboplatin or oxaliplatin. The renal excretion fractions for free carnitine and acylcarnitines increased 4-10 times during treatment with platin derivatives. Renal excretions of alpha1-microglobulin and other proximal tubular markers were also increased, compatible with a proximal tubular defect. Direct inhibition of OCTN2 expressed in L6 cells by cisplatin, oxaliplatin or platinum(2+) could not be demonstrated, and experiments using urine from patients treated with cisplatin inhibited OCTN2 activity no more than expected from the carnitine content in the respective urine sample. Cisplatin was associated with a time- and concentration-dependent decrease of OCTN2 mRNA and protein expression in 293-EBNA cells.

CONCLUSIONS

All platin derivatives investigated are associated with renal tubular damage in humans without significantly affecting glomerular function. The rapid onset and complete reversibility of this effect favour a functional mechanism such as impaired expression of OCTN2 in proximal tubular cells.

Studies on the protective effect of green tea against cisplatin induced nephrotoxicity

Cisplatin (CP) an anticancer drug is known to induce nephrotoxicity, which limits its long-term clinical use. Green tea (GT), consumed since ancient times is known for its numerous health benefits. It has been shown to improve kidney functions in animal models of acute renal failure. The present study was undertaken to see whether GT can prevent CP-induced nephrotoxic and other deleterious effects. A nephrotoxic dose of CP was co-administered to control and GT-fed male Wistar rats every fifth day for 25 days. The effect of GT was determined on CP-induced alterations in various serum parameters and on enzymes of carbohydrate metabolism, brush border membrane, and antioxidant defense system in renal cortex and medulla. CP nephrotoxicity was recorded by increased serum creatinine and blood urea nitrogen. CP increased the activities of lactate dehydrogenase and acid phosphatase whereas, the activities of malate dehydrogenase, glucose-6-phosphatase, superoxide dismutase, catalase, and (32)Pi transport significantly decreased. GT consumption increased the activities of the enzymes of carbohydrate metabolism, brush border membrane, oxidative stress, and (32)Pi transport. GT ameliorated CP-induced nephrotoxic and other deleterious effects due to its intrinsic biochemical/antioxidant properties.

Carboplatin-induced alteration of the thiol homeostasis in the isolated perfused rat kidney

Carboplatin elicits minor side effects with respect to its first generation analogue cisplatin. Nevertheless, a dose-dependent nephrotoxicity of the drug has been reported to occur both in patients and in rats and a possible pathogenic role have been attributed to oxidative stress. We have studied the effect of carboplatin administration on the thiol/disulfide balance, on other biomarkers of oxidative stress and on antioxidant enzymes in the isolated perfused rat kidney. A 5-500microM carboplatin dose range did not alter renal function but significantly decreased levels of cysteine, glutathione and exposed protein sulfhydryl groups. Only a minimal increment in disulfides was observed, whereas malonyldialdehyde and protein carbonyls did not increase significantly. Among the antioxidant enzymes studied, only thioltransferase was inhibited by the treatment. Our data suggest that a minimal oxidative stress is present under our experimental conditions, thus indicating that platinum-based drugs do not produce significant amount of reactive oxygen species.

Neuronal expression of copper transporter 1 in rat dorsal root ganglia: association with platinum neurotoxicity

PURPOSE

We report the neuronal expression of copper transporter 1 (CTR1) in rat dorsal root ganglia (DRG) and its association with the neurotoxicity of platinum-based drugs.

METHODS

CTR1 expression was studied by immunohistochemistry and RT-PCR. The toxicity of platinum drugs to CTR1-positive and CTR1-negative neurons was compared in DRG from animals treated with maximum tolerated doses of oxaliplatin (1.85 mg/kg), cisplatin (1 mg/kg) or carboplatin (8 mg/kg) twice weekly for 8 weeks.

RESULTS

Abundant CTR1 mRNA was detected in DRG tissue. CTR1 immunoreactivity was associated with plasma membranes and cytoplasmic vesicular structures of a subpopulation (13.6 +/- 3.1%) of mainly large-sized (mean cell body area, 1,787 +/- 127 microm(2)) DRG neurons. After treatment with platinum drugs, the cell bodies of these CTR1-positive neurons became atrophied, with oxaliplatin causing the greatest percentage reduction in the mean cell body area relative to controls (42%; P < 0.05), followed by cisplatin (18%; P < 0.05) and carboplatin causing the least reduction (3.2%; P = NS). CTR1-negative neurons, with no immunoreactivity or only diffuse cytoplasmic staining, showed less treatment-induced cell body atrophy than CTR1-positive neurons.

CONCLUSIONS

CTR1 is preferentially expressed by a subset of DRG neurons that are particularly vulnerable to the toxicity of platinum drugs. These findings, together with its neuronal membrane localization, are suggestive of CTR1-related mechanisms of platinum drug neuronal uptake and neurotoxicity.

The first clinical use of a live-attenuated Listeria monocytogenes vaccine: a Phase I safety study of Lm-LLO-E7 in patients with advanced carcinoma of the cervix

Invasive carcinoma of the cervix (ICC) is the second most common cancer in women worldwide. Lm-LLO-E7 vaccine is a live-attenuated Listeria monocytogenes (Lm) that secretes the HPV-16 E7 antigen fused to a non-hemolytic fragment of the Lm protein listeriolysin O (LLO). In this Phase I trial, the safety of Lm-LLO-E7 was assessed in 15 patients with previously treated metastatic, refractory or recurrent ICC. Patients received 1 of 3 dose levels of Lm-LLO-E7 (1 x 10(9)CFU, 3.3 x 10(9)CFU or 1 x 10(10)CFU) as an intravenous infusion, followed by a second dose 3 weeks later. All patients experienced a flu-like syndrome which responded to non-prescription symptomatic treatment. Severe (grade 3) adverse events related to Lm-LLO-E7 were reported in 6 patients (40%), but no grade 4 adverse events were observed. At the highest dose some patients had severe fever and dose limiting hypotension. By the end of the study protocol, 2 patients had died, 5 had progressed, 7 had stable disease and 1 qualified as a partial responder. This study shows for the first time that a live-attenuated Lm is safe to be administered to late stage ICC patients.

Platinum neurotoxicity pharmacogenetics

Cisplatin, carboplatin, and oxaliplatin anticancer drugs are commonly used to treat lung, colorectal, ovarian, breast, head and neck, and genitourinary cancers. However, the efficacy of platinum-based drugs is often compromised because of the substantial risk for severe toxicities, including neurotoxicity. Neurotoxicity can result in both acute and chronic debilitation. Moreover, colorectal cancer patients treated with oxaliplatin discontinue therapy more often because of peripheral neuropathy than tumor progression, potentially compromising patient benefit. Numerous methods to prevent neurotoxicity have thus far proven unsuccessful. To circumvent this life-altering side effect while taking advantage of the antitumor activities of the platinum agents, efforts to identify mechanism-based biomarkers are under way. In this review, we detail findings from the current literature for genetic markers associated with neurotoxicity induced by single-agent and combination platinum chemotherapy. These data have the potential for broad clinical implications if mechanistic associations lead to the development of toxicity modulators to minimize the noxious sequelae of platinum chemotherapy.

Interaction of Cisplatin with the human organic cation transporter 2

PURPOSE

Cisplatin is predominantly eliminated in the urine through active secretion. As the solute carrier organic cation transporter 2 (OCT2) is highly expressed in the basolateral membrane of proximal tubules, we determined its contribution to cisplatin transport and assessed the relation of variation in the gene encoding OCT2 (SLC22A2) with the disposition of cisplatin.

EXPERIMENTAL DESIGN

Cell lines were transfected using the Flp-In 293 system with the full-length OCT2 cDNA, and platinum concentrations were measured using flameless atomic absorption spectrometry. Pharmacokinetic data were available from 106 cancer patients, and DNA was screened for eight nonsynonymous SLC22A2 variants using direct sequencing.

RESULTS

mRNA expression was 36-fold higher and uptake of the model substrate tetraethylammonium was significantly increased (P < 0.0001) in OCT2-transfected cells compared with empty vector-transfected controls. OCT2-mediated transport of cisplatin was saturable, and uptake was increased by approximately 4-fold (P < 0.0001) relative to control cells. Cisplatin inhibited OCT2-mediated transport of tetraethylammonium by up to 97%. The mean +/- SD systemic clearance of unbound cisplatin-derived platinum in the patient population was 29.2 +/- 8.39 L/h, and renal clearance was particularly variable. Only one single nucleotide polymorphism (Ala270Se; rs316019) was identified (minor allele frequency, 7.6%), and it was not found to be associated with any of the studied pharmacokinetic variables (P > 0.05).

CONCLUSION

These findings support the hypothesis that OCT2 is a key renal transporter involved in cisplatin elimination. However, known variants in SLC22A2 do not substantially contribute to explaining interindividual pharmacokinetic variability, suggesting that other mechanisms, controlling OCT2 expression, might be involved.

Study by HPLC-MS of the interaction of platinum antitumor complexes with potato carboxypeptidase inhibitor (PCI)

The interaction of the well-known antitumor drug cisplatin cis-[PtCl(2)(NH(3))(2)] and the compound trans-[PtCl(2)NH(3)(4-hydroxymethylpyridine)] with the small protein potato carboxypeptidase inhibitor (PCI) and a PCI mutant in which glycine-39 was substituted by methionine has been followed by HPLC/mass spectrometry. Our results showed that both Pt drugs were able to bind PCI through Met-39 and histidines in mutated PCI, whereas only the trans complex interacted significantly with wild PCI. In the cytotoxic studies, the monofunctional adduct PCI-Met-cisplatin was neither more active nor more selective than cisplatin itself when tested against three tumor cell lines with different number of EGF receptors. Those results suggested that the poor activity of the adduct could be just due to the small fraction of cisplatin which was decoordinated from the adduct and able to penetrate the tumor cells, as well as to the changes in the structure of the platinum drug after the loss of NH(3) groups upon binding PCI-Met.

Chemotherapy-induced neuropathy

Neurotoxic side effects of cancer therapy are second in frequency to hematological toxicity. Unlike hematological side effects that can be treated with hematopoietic growth factors, neuropathies cannot be treated and protective treatment strategies have not been effective. For the neurologist, the diagnosis of a toxic neuropathy is primarily based on the case history, the clinical and electrophysiological findings, and knowledge of the pattern of neuropathy associated with specific agents. In most cases, toxic neuropathies are length-dependent, sensory, or sensorimotor neuropathies often associated with pain. The platinum compounds are unique in producing a sensory ganglionopathy. Neurotoxicity is usually dependent on cumulative dose. Severity of neuropathy increases with duration of treatment and progression stops once drug treatment is completed. The platinum compounds are an exception where sensory loss may progress for several months after cessation of treatment ("coasting"). As more effective multiple drug combinations are used, patients will be treated with several neurotoxic drugs. Synergistic neurotoxicity has not been extensively investigated. Pre-existent neuropathy may influence the development of a toxic neuropathy. Underlying inherited or inflammatory neuropathies may predispose patients to developing very severe toxic neuropathies. Other factors such as focal radiotherapy or intrathecal administration may enhance neurotoxicity. The neurologist managing the cancer patient who develops neuropathy must answer a series of important questions as follows: (1) Are the symptoms due to peripheral neuropathy? (2) Is the neuropathy due to the underlying disease or the treatment? (3) Should treatment be modified or stopped because of the neuropathy? (4) What is the best supportive care in terms of pain management or physical therapy for each patient? Prevention of toxic neuropathies is most important. In patients with neuropathy, restorative approaches have not been well established. Symptomatic and other management are necessary to maintain and improve quality of life.

Hearing loss in pediatric oncology patients receiving carboplatin-containing regimens

Carboplatin is a well-established chemotherapeutic agent used to treat a variety of pediatric malignancies. Platinum analogues such as cisplatin are known to be ototoxic, but little is known regarding the ototoxicity of carboplatin. We performed a single institution retrospective chart review of pediatric oncology patients who received platinum-containing regimens from 1993 to 2002. Ninety-nine patients with sufficient medical and audiologic data were identified. Significant hearing loss was defined as a Brock grade 1 or higher. The incidence was compared among 3 treatment groups (carboplatin only, carboplatin and cisplatin, and cisplatin only). Significant hearing loss in patients receiving carboplatin only was rare, observed in only 1/25 (4%) of patients. In contrast, 19/27 (70%) of patients receiving carboplatin and cisplatin possessed significant hearing loss, as did 27/47 (57%) of those patients receiving cisplatin only P<0.001. The difference in hearing loss could not be explained by different cumulative exposures of the platinum agents. Carboplatin, when used without cisplatin, is rarely associated with severe hearing loss, even at high cumulative doses.

Auditory monitoring in ototoxicity

Some pharmaceutical products are capable of damaging the human auditory system. Technological progress has provided numerous resources to monitor hearing but there still is some controversy regarding the selection of the most sensitive and specific tests.

OBJECTIVE

to analyze audiological procedures used in the auditory monitoring of individuals exposed to ototoxic medication.

METHODS

we searched the MEDLINE and LILACS literature databases, using terms pertinent to audiological monitoring, ototoxicity and cancer. The pertaining literature analysis identified two procedures often used worldwide for the early detection of auditory lesions induced by ototoxic pharmaceutical drugs: high-frequency audiometry and evoked otoacoustic emissions. Both allow early identification of hearing disorders before changes are seen in conventional pure-tone audiometry and, consequently, before speech understanding is compromised.

CONCLUSION

we suggest a hearing monitoring protocol, considering the patients capability to respond to behavioral tests and monitoring timing (first test/follow up). For cancer patients, hearing monitoring should be performed in the patients treatment venue.

Recovery from cisplatin-induced ototoxicity: a case report and review

We present a pediatric case report of cisplatin-induced ototoxicity with subsequent recovery. The patient experienced tinnitus and fluctuating mild high-frequency sensorineural hearing loss (SNHL) with a concomitant decrease in distortion product otoacoustic emissions (DPOAE). There was recovery of hearing loss and return of DPOAE at 1 year after completion of cisplatin therapy. Reports of recovery from cisplatin-induced ototoxicity in humans are limited in the literature, especially in the pediatric population. A review of cisplatin ototoxicity and mechanisms of recovery are discussed, with an emphasis on the particular chemotherapy regimen and dosing schedule in this case, given at 4-11 week intervals.

Mechanisms of cisplatin ototoxicity and progress in otoprotection

PURPOSE OF REVIEW

This review presents exciting new data published in the past year that help to elucidate the mechanisms of cisplatin ototoxicity. Recent research findings on otoprotection could lead to the development of novel protective agents. Cisplatin ototoxicity is a frequent and serious problem in patients. Strategies to ameliorate ototoxicity without interfering with the desired therapeutic effects are urgently needed.

RECENT FINDINGS

Cisplatin ototoxicity appears to involve the production of reactive oxygen species in target tissues in the inner ear by activating an enzyme unique to the cochlea. This leads to a cascade resulting in oxidation of lipids and cell death. The upregulation of endogenous protective mechanisms in the cochlea or treatment with exogenous compounds reduces ototoxicity in cisplatin-treated animals. The only clinical trials reported to date with the putative protective agent, amifostine, have been disappointing.

SUMMARY

The data summarized in this paper could lead to important clinical trials to determine whether the findings in experimental animals can translate into effective treatments to prevent cisplatin ototoxicity.

The anticancer drug cisplatin induces an intrinsic apoptotic pathway inside the inner ear

BACKGROUND AND PURPOSE

Ototoxicity is a known adverse effect of cisplatin (CDDP). Since apoptosis is involved in the development of some pathological conditions associated with the administration of anticancer drugs, we examined, using immunohistochemical and electrophysiological techniques, the apoptotic changes in the cochlea of Sprague-Dawley (SD) rats after an injection of CDDP (5 mgkg(-1) body weight).

EXPERIMENTAL APPROACH

Luciferase assays were used to determine the different caspase activities and ATP levels in protein extracts of whole cochleae. The expression of several apoptotic-related proteins was measured by means of Western blotting. These analyses were performed 2, 7 and 30 days after the CDDP injection. The auditory brain stem response was obtained before and at the different times after the injection of CDDP, before the animals were killed.

KEY RESULTS

CDDP significantly increased the levels of caspase-3/7 activity and active caspase-3 protein expression and caspase-3 immunofluorescence staining, caspase-9 activity, and Bax protein expression but decreased Bcl-2 protein expression within the rat cochleae. Threshold shifts were significantly elevated 2 days after CDDP treatment.

CONCLUSIONS AND IMPLICATIONS

These findings support the hypothesis that cisplatin-related apoptosis evokes an intrinsic pathway of pro-apoptotic signalling within the rat cochleae. Thus, selective inhibition of the sequence of events involved in the intrinsic apoptotic pathway could provide a strategy to minimize cisplatin-induced ototoxicity.

Effect of cisplatin on brush border membrane enzymes and anti-oxidant system of rat intestine

Cisplatin (CP) is a widely used antineoplastic agent which exhibits gastrointestinal toxicity. The present work was done to study the effect of administration of CP on brush border membrane (BBM) enzymes and anti-oxidant system of rat intestine. Male Wistar rats were given a single intraperitoneal dose of CP (6 mg/kg body weight) and then sacrificed 1, 3, 5 and 7 days after this treatment. Control animals were given saline only. The administration of CP led to significant decline in the specific activities of BBM enzymes both in the mucosal homogenates and isolated membrane vesicles. Kinetic studies showed that the V(max) of the enzymes was decreased in BBM vesicles from CP treated rats while the K(m) remained unchanged. The activities of catalase, Cu-Zn superoxide dismutase, glucose 6-phosphate dehydrogenase and glutathione reductase decreased while the activities of glutathione S-transferase and thioredoxin reductase increased in CP treated animals compared to the control group. Lipid peroxidation and total sulfhydryl groups were also altered upon CP treatment indicating the generation of oxidative stress. The maximum changes in all the parameters studied above were 3 days after administration of CP and then recovery took place on days 5 and 7. Thus, the administration of CP leads to significant alterations in the activities of BBM enzymes and the anti-oxidant status of rat intestine.

Mechanisms of resistance to cisplatin and carboplatin

While cisplatin and carboplatin are active versus most common cancers, epithelial malignancies are incurable when metastatic. Even if an initial response occurs, acquired resistance due to mutations and epigenetic events limits efficacy. Resistance may be due to excess of a resistance factor, to saturation of factors required for tumor cell killing, or to mutation or alteration of a factor required for tumor cell killing. Platinum resistance could arise from decreased tumor blood flow, extracellular conditions, reduced platinum uptake, increased efflux, intracellular detoxification by glutathione, etc., decreased binding (e.g., due to high intracellular pH), DNA repair, decreased mismatch repair, defective apoptosis, antiapoptotic factors, effects of several signaling pathways, or presence of quiescent non-cycling cells. In lung cancer, flattening of dose-response curves at higher doses suggests that efficacy is limited by exhaustion of something required for cell killing, and several clinical observations suggest epigenetic events may play a major role in resistance.

International Society of Geriatric Oncology (SIOG) recommendations for the adjustment of dosing in elderly cancer patients with renal insufficiency

A SIOG taskforce was formed to discuss best clinical practice for elderly cancer patients with renal insufficiency. This manuscript outlines recommended dosing adjustments for cancer drugs in this population according to renal function. Dosing adjustments have been made for drugs in current use which have recommendations in renal insufficiency and the elderly, focusing on drugs which are renally eliminated or are known to be nephrotoxic. Recommendations are based on pharmacokinetic and/or pharmacodynamic data where available. The taskforce recommend that before initiating therapy, some form of geriatric assessment should be conducted that includes evaluation of comorbidities and polypharmacy, hydration status and renal function (using available formulae). Within each drug class, it is sensible to use agents which are less likely to be influenced by renal clearance. Pharmacokinetic and pharmacodynamic data of anticancer agents in the elderly are needed in order to maximise efficacy whilst avoiding unacceptable toxicity.

Progress in Anti-SARS Coronavirus Chemistry, Biology and Chemotherapy

Proteolytic processing of the coronavirus replicase polyproteins is essential for ongoing viral ribonucleic acid (RNA) synthesis. Therefore, the severe acute respiratory syndrome (SARS)-coronaviruses (SARS-CoV) proteases are attractive targets for the development of antiviral drugs to reduce viral replication and pathogenicity. The structure and activity of the coronavirus 3C-like protease (3CLpro) has already been elucidated, and the design of inhibitors to 3CLpro as therapeutics has been proposed. The chapter discusses SARS-CoV 3CLpro inhibitors that include covalent inhibitors, noncovalent inhibitors, and inhibitors from screening. SARS-CoV papain-like protease (PLpro) is considered an equally viable target to 3CLpro for drug design because both are essential for viral replication. However, PLpro has likely not been pursued because of the paucity of structural information. Several compounds have been identified that have shown inhibitory activity against SARS-CoV. However, no information regarding their mechanism of action or the corresponding target is known. Glycyrrhizin showed inhibitory activity for SARS-CoV replication with EC50 = 300 mg/L after virus absorption in Vero cells. Some glycyrrhizin acid derivatives were found to inhibit SARS-CoV replication in vitro with EC50 values ranging from 5 to 50 μ M. Unfortunately, these compounds show high cytotoxity.

MLH1-deficient tumor cells are resistant to lipoplatin, but retain sensitivity to lipoxal

Lipoplatin, currently under phase III evaluation, is a novel liposomal cisplatin formulation highly effective against cancers. Lipoplatin has eliminated or reduced the systemic toxicity frequently seen for cisplatin. The objective of the present study was to determine whether the cytotoxic effect of lipoplatin is dependent on the functional integrity of DNA mismatch repair (MMR), a post-replicative DNA repair machinery implicated in cell cycle control and apoptosis. Clonogenic data revealed a significant (P<0.05) 2-fold resistance to lipoplatin of HCT116 human colorectal adenocarcinoma cells lacking MLH1, one of five proteins crucial to MMR function, as compared to MLH1-expressing HCT116 cells. In addition, MLH1-deficient cells were at least 3-fold less susceptible to apoptosis (DNA fragmentation) than MLH1-proficient cells. However, proteolytic processing of caspase-3, caspase-7 and poly(ADP-ribose)polymerase-1 following lipoplatin treatment was comparable in MLH1-deficient cells and -proficient cells. Furthermore, MLH1-deficient cells retained the ability to attenuate cell cycle progression past the G2/M checkpoint following lipoplatin treatment. In conclusion, our results indicate that the lipoplatin-sensitive phenotype of MLH1-proficient cells correlated with increased apoptosis which may occur via caspase-independent pathways. They also suggest that the integrity of MMR function is a relevant determinant accounting for the cytotoxicity of lipoplatin. However, this does not seem to apply to lipoxal, a novel liposomal formulation of oxaliplatin, because MLH1-deficient cells were as sensitive to lipoxal as MLH1-proficient cells.

Mechanisms of cisplatin-induced ototoxicity and prevention

Cisplatin is a widely used chemotherapeutic agent to treat malignant disease. Unfortunately, ototoxicity occurs in a large percentage of patients treated with higher dose regimens. In animal studies and in human temporal bone investigations, several areas of the cochlea are damaged, including outer hair cells in the basal turn, spiral ganglion cells and the stria vascularis, resulting in hearing impairment. The mechanisms appear to involve the production of reactive oxygen species (ROS), which can trigger cell death. Approaches to chemoprevention include the administration of antioxidants to protect against ROS at an early stage in the ototoxic pathways and the application of agents that act further downstream in the cell death cascade to prevent apoptosis and hearing loss. This review summarizes recent data that shed new light on the mechanisms of cisplatin ototoxicity and its prevention.

Human primary renal cells as a model for toxicity assessment of chemo-therapeutic drugs

Chemo-therapeutic drugs act on cancerous and normal cells non-selectively and often cause organ impairments during treatment. Improving safety or reducing toxicity becomes an important challenge for developing better anticancer drugs. In the present study, effects of selected anticancer drugs (camptothecin, doxorubicin, colchicine, paclitaxel, cisplatin, and carboplatin) on cell viability and proliferation was investigated. The anti-proliferative activity of each drug on cancer cells (human hepatoma HepG2) and human primary renal proximal tubule cells (hRPTECs and LLC-PK1) was determined with the [(3)H]thymidine incorporation assay. Results indicated all six drugs blocked cell proliferation in cancer and normal cells. When the anti-proliferation potency was ranked in hRPTECs based on EC50 values, camptothecin is the most potent, followed by doxorubicin, paclitaxel, colchicine, cisplatin and carboplatin. Cytotoxicity of drugs to hRPTECs was assessed with the ATP bioluminescence assay. Doxorubicin and cisplatin were known to induce nephrotoxicity in vivo and they were indeed cytotoxic to hRPTECs in our study with EC50 values at 11.2 and 39.6 microM. All other drugs are not cytotoxic in the concentrations tested. These drugs typically displayed separation of EC50s between potency (anti-proliferation) and cytotoxicity. The dose separation provides a concentration range for each drug to act on cell proliferation without induction of significant cytotoxicity. Our results suggest that hRPTEC system can serve as an in vitro model for assessing potential nephrotoxicity of chemo-therapeutic drugs.

Ischemic necrosis and atrophy of the optic nerve after periocular carboplatin injection for intraocular retinoblastoma

PURPOSE

To report four cases of optic nerve neuropathy in three children treated with periocular carboplatin injections for unilateral or bilateral intraocular retinoblastoma.

DESIGN

Retrospective, observational case series.

METHODS

SETTING

University-based Ophthalmology Practice.

STUDY POPULATION

Four eyes of three children with retinoblastoma enucleated after nonsuccessful multimodality treatment including periocular carboplatin injections.

OBSERVATION PROCEDURES

The enucleated eyes were routinely processed and evaluated by light microscopy. A retrospective chart review of all four cases was performed.

RESULTS

Three enucleated eyes (Reese-Ellsworth groups III and VB) were obtained from two children with bilateral multifocal retinoblastoma, and one eye (Reese-Ellsworth group IIB) was harvested from a child with unilateral retinoblastoma. All affected eyes underwent three to seven periocular carboplatin injections before enucleation. Additional treatment modalities included systemic chemotherapy, transpupillary thermotherapy, transscleral cryotherapy, and external beam radiotherapy. Histopathologic evaluation of the enucleated eyes revealed focal areas of ischemic necrosis or atrophy of the optic nerve along with dystrophic calcification and mild inflammation in the surrounding fibrovascular adipose tissue.

CONCLUSIONS

Periocular injections of carboplatin may be a useful treatment approach in the management of patients with advanced intraocular retinoblastoma and may minimize systemic side-effects. However, ophthalmologists and pediatric oncologists should be aware of potential marked local complications with periocular carboplatin delivery, including ischemic optic neuropathy. Modifying the injection site/location (for example, subtenon space) or adding other delivery routes adjuncts (for example, fibrin sealant) deserves further study.

Dose Individualization of Carboplatin After a 120-hour Infusion Schedule: Higher Dose Intensity but Fewer Toxicities

Carboplatin (CBDCA) is a widely used anticancer agent for which dose-effect and dose-toxicity relationships have been demonstrated, thus stressing the need for a controlled exposure to this drug. So far, carboplatin administration could only be individualized a priori following 2 classic methods, which are based on the evaluation of renal clearance: Calvert's and Chatelut's formulas. This study was designed to develop and evaluate the performance of an alternative CBDCA 120-hour schedule coupled to a Bayesian adaptive dosing with feedback strategy. Precision of the dosing method was assessed in 84 patients (256 courses performed during a 10-year period), by comparing CBDCA plasma concentrations observed at the end of the infusion with initial target values. A comprehensive monitoring of treatment-related toxicities also was performed. Finally, the authors compared doses actually delivered following the dose-tailoring method with the theoretical, standard, ones calculated retrospectively with Calvert's and Chatelut's formulas. No significant differences were found between experimental and theoretical concentrations. According to the target exposure chosen (3 levels), the mean doses administered to our patients were 517, 719, and 902 mg of CBDCA compared with 550, 509, and 538 or 657, 604, and 644 mg, which would have been given following Calvert or Chatelut formulas, respectively. These results showed that our Bayesian method led to the administration of up to 60% higher doses of carboplatin compared with those based only on the evaluation of renal clearance. Despite the markedly higher doses administered, no severe toxicities were reported in the patients treated following this new schedule. It is noteworthy that neither hematologic growth factors nor stem cells, usually associated with high-dose regimen, were used as support in this study. These data strongly suggest that it is possible to deliver higher dose- intensities of carboplatin, even in elderly, unselected patients, without increasing toxicities and with no growth factor support, provided that a therapeutic drug monitoring strategy with real-time tailored dosing is performed.

High accumulation of platinum-DNA adducts in strial marginal cells of the cochlea is an early event in cisplatin but not carboplatin ototoxicity

Ototoxicity is a typical dose-limiting side effect of cancer chemotherapy with cisplatin but much less so with carboplatin. To elucidate the underlying molecular pathological mechanisms, we have measured the formation and persistence of drug-induced DNA adducts in the nuclei of inner ear cells of guinea pigs after short-term exposure to either cisplatin or carboplatin using immunofluorescence staining and quantitative image analysis. After application of carboplatin, all cells of the cochlea exhibited a similar burden of guanine-guanine intrastrand cross-links in DNA. In contrast, we observed a pronounced 3- to 5-fold accumulation of this cytotoxic adduct exclusively in the marginal cells of the stria vascularis between 8 and 48 h after treatment with cisplatin. In the kidney, the other critical target tissue of cisplatin toxicity, a similar high preferential formation of cytotoxic DNA adducts was measured in the tubular epithelial cells but not in other renal cell types. As for the ear, this excessive formation of DNA damage in a particular cell type was seen in animals treated with cisplatin but not those treated with carboplatin. Because cisplatin ototoxicity is often attributed to oxidative stress mediated by the generation of radical oxygen species (ROS), we have measured in parallel the levels of the lead DNA oxidation product 8-oxoguanine (8-oxoG) in cochlear cryosections. Compared with basal levels in untreated control cochleas, no additional formation of 8-oxoG was detectable up to 48 h after cisplatin treatment in the DNA of either inner-ear cell type. This suggests that the generation of ROS may be a secondary event in cisplatin ototoxicity.

Down-regulation of hepatic cytochrome P450 enzymes associated with cisplatin-induced acute renal failure in male rats

Hepatic drug metabolism is impaired in experimental animals and humans with renal diseases. An anticancer drug, cisplatin induces acute renal failure (ARF) in rats. Under the same experimental conditions, cisplatin causes down-regulation of hepatic cytochrome P450 (P450) enzymes in an isozyme selective manner. The present study examined the pathological role of ARF in the down-regulation of hepatic P450 enzymes in the cisplatin-treated rats. Male rats with single dose of intraperitoneally cisplatin (5 mg/kg) caused marked changes in renal parameters, BUN and serum creatinine but not hepatic parameters, serum alanine aminotransferase or aspartate aminotransferase. The rats also suffered from down-regulation of hepatic microsomal CYP2C11 and CYP3A2, male specific P450 isozymes, but not CYP1A2, CYP2E1, or CYP2D2. The decrease in serum testosterone level was also observed in injured rats, which was consistent with the selective effects on male specific P450 enzymes. Protection of rats against cisplatin-induced ARF by dimethylthiourea, a hydroxyl radical scavenger, also protected rats against the decrease in serum testosterone levels and the down-regulation of CYP2C11 and CYP3A2. Carboplatin, an analogue to cisplatin but no ARF inducer, did not cause decrease in serum testosterone levels and down-regulation of hepatic male specific P450 enzymes. These results suggest that down-regulation of hepatic P450 enzymes in male rats given cisplatin is closely related to the cisplatin-induced ARF and the resultant impairment of testis function.

Expression of the kidney injury molecule 1 in the rat cochlea and induction by cisplatin

Cisplatin is a widely used chemotherapeutic agent whose dose-limiting side effects include ototoxicity and nephrotoxicity. Recent evidence indicates that cisplatin induces the expression of a novel protein, kidney injury molecule-1, in the renal proximal tubular epithelium to aid in regeneration. In this study, we determined whether kidney injury molecule-1 is expressed in the cochlea and is induced by cisplatin. Using reverse transcriptase polymerase chain reaction techniques, we have now identified kidney injury molecule-1 in the rat cochlea and in three different mouse transformed hair cell lines. Administration of cisplatin to rats produced hearing loss and induced kidney injury molecule-1 mRNA in the rat cochlea. Pretreatment of rats with lipoic acid, a scavenger of reactive oxygen species, significantly reduced cisplatin-induced hearing loss and kidney injury molecule-1 expression. Cisplatin also increased the expression of cochlear NOX3 mRNA, a member of the superoxide generating NADPH oxidase family of proteins recently identified in the cochlea, inhibition of which decreased kidney injury molecule-1 expression. Polymerase chain reaction performed on different regions of the cochlea indicated the presence of kidney injury molecule-1 mRNA in the lateral wall, organ of Corti and spiral ganglion. This distribution was confirmed by immunocytochemistry. Taken together, these data identify kidney injury molecule-1 as a novel cochlear injury molecule, whose expression is regulated by reactive oxygen species generated via the NADPH oxidase pathway.

Metastatic osteosarcoma

BACKGROUND

The outcome of patients with metastatic osteosarcoma treated in two consecutive trials from 1986 to 1997 was analyzed to evaluate the efficacy of carboplatin-based multiagent chemotherapy and to identify prognostic factors. The initial study (OS-86) used ifosfamide, cisplatin, doxorubicin, and high-dose methotrexate, and the subsequent study (OS-91) used the same agents at similar doses, but carboplatin was substituted for cisplatin.

METHODS

Twelve patients (median age, 15.1 yrs) were treated in OS-86 for osteosarcoma metastatic to the lung only (11 patients) or bone only (1 patient), and 17 patients (median age, 15.1 yrs) were treated in OS-91 for osteosarcoma metastatic to the lung only (12 patients), bone only (2 patients), lung and bone (2 patients), or other site (1 patient).

RESULTS

Patients with metastatic disease enrolled in OS-86 and those with metastatic disease enrolled in OS-91 did not differ in terms of demographic features, histologic subtype, site of primary tumor, or site of metastases. There was a difference in survival according to treatment protocol (P = 0.054). All survivors (four of whom were enrolled in OS-86 and one of whom was enrolled in OS-91) had lung metastases only. Five-year survival estimates for patients with lung metastases only were 45.5 +/- 13.7% (OS-86) and 8.3 +/- 5.6% (OS-91) (P = 0.084). Unilateral lung metastases (P = 0.006), no more than three lung nodules (P = 0.014), and surgical remission (P = 0.001) were associated with improved survival probability.

CONCLUSIONS

The poor outcome of patients with metastatic osteosarcoma treated in OS-91 justifies the use of cisplatin with its associated toxicity in patients with high-risk disease.

Amino acid concentrations in chinchilla cochlear nucleus at different times after carboplatin treatment

Amino acid concentrations were measured in the cochlear nucleus for a group of 20 chinchillas: four each of control and 4, 8, 29, and 85 days after treatment with the ototoxic anti-tumor drug carboplatin (100 mg/kg, i.p.). The treated chinchillas showed various extents of inner hair cell loss, generally more complete at longer survival times, but little loss of outer hair cells. Aspartate concentration in rostral anteroventral cochlear nucleus (AVCN) showed a decline to 28% less than the control value at 29 and 85 days after treatment, whereas glutamate concentration showed little change through 29 days, then dropped by 22% at 85 days after treatment. In caudal posteroventral cochlear nucleus (PVCN), the aspartate concentration decreased by 32% at 29 days, in animals with significant inner hair cell loss, and 48% at 85 days after treatment, while the glutamate concentration showed no decrease through 29 days and 40% decrease at 85 days. The concentration of gamma-aminobutyrate (GABA) was about 18% lower than control in caudal PVCN at all survival times. Significant correlations were found between the proportion of inner hair cells remaining and glutamate and aspartate concentrations in PVCN and AVCN, but not GABA or other amino acids.

Hematologic Safety and Tolerability of Topotecan in Recurrent Ovarian Cancer and Small Cell Lung Cancer: An Integrated Analysis

The purpose was to conduct an integrated analysis of the cumulative hematologic toxicity of topotecan in patients with relapsed ovarian cancer and small cell lung cancer (SCLC). Data were pooled from eight phase II and phase III clinical studies performed in patients with relapsed stage III/IV ovarian cancer or extensive SCLC treated with topotecan at a dose of 1.5 mg/m(2) per day on days 1-5 of a 21-day course. Quantitative hematologic toxicities were assessed using the National Cancer Institute Common Toxicity Criteria. A total of 4,124 courses of therapy was administered to the 879 patients in the pooled population. Grade 4 neutropenia was experienced by 78% of patients. The lowest nadirs for neutrophils and platelets generally occurred after the first course of therapy, followed by improvement or stabilization in subsequent courses. Neutropenia was noncumulative. During the first course, significant risk factors were identified: renal impairment and advanced age (grade 3/4 thrombocytopenia and grade 4 neutropenia) and prior radiotherapy; performance status score > or =2; SCLC; and exposure to both cisplatin (Platinol; Bristol-Myers Squibb, Princeton, NJ, http://www.bms.com) and carboplatin (Paraplatin; Bristol-Myers Squibb) (grade 3/4 thrombocytopenia only). The most frequent interventions for hematologic toxicities were RBC transfusions, treatment delays, G-CSF support, and dose reductions. Analysis of neutrophil and platelet nadirs and dosing for each course of therapy showed no apparent evidence of cumulative neutropenia or thrombocytopenia. The risk of grade 3 or 4 anemia was higher during the first four courses of therapy and may need to be more aggressively managed with erythropoietin therapy.

Clinical management of oxaliplatin-associated neurotoxicity

In recent years, oxaliplatin-based chemotherapy protocols, particularly oxaliplatin in combination with infusional 5-fluorouracil/leucovorin (FOLFOX or FUFOX), have emerged as the standard of care in first- and second-line therapy of advanced-stage colorectal cancer. Although oxaliplatin by itself has only mild hematologic and gastrointestinal side effects, its clinically dominating toxicity affects the peripheral sensory nervous system in the form of 2 distinct types of neurotoxicity: (1) a unique, frequent, acute sensory neuropathy that is triggered or aggravated by exposure to cold but at the same time is rapidly reversible without persistent impairment of sensory functions; (2) the dose-limiting toxicity of oxaliplatin, a cumulative, chronic sensory neurotoxicity that resembles that of cisplatin with the important difference of its being more rapidly and completely reversible. This chronic sensory neurotoxicity is highly predictable, being closely associated with the cumulative dose of oxaliplatin that is administered. Various strategies have been proposed to prevent or treat oxaliplatin-induced neurotoxicity. The stop-and-go concept uses the predictability and reversibility of neurologic symptoms to allow patients to stay on an oxaliplatin-containing first-line therapy for a prolonged period. Several neuromodulatory agents such as calcium-magnesium infusions; antiepileptic drugs like carbamazepine, gabapentin, and venlafaxine; amifostine; a-lipoic acid; and glutathione have demonstrated some activity in the prophylaxis and treatment of oxaliplatin-induced acute neuropathy. However, randomized trials demonstrating a prophylactic or therapeutic effect on oxaliplatin's cumulative neurotoxicity are still lacking. The predictability of neurotoxicity associated with oxaliplatin-based therapy should allow patients and doctors to develop strategies to manage this side effect in view of the individual patient's clinical situation. This is of increasing importance, because the addition of bevacizumab to FOLFOX will conceivably further prolong the progression-free survival achieved with FOLFOX so that neurotoxicity and not tumor progression could become the dominating treatment-limiting issue in the first-line therapy of advanced colorectal cancer.

Nephrotoxicity of a novel antineoplastic platinum complex, nedaplatin: a comparative study with cisplatin in rats

The present study was designed to characterize the nephrotoxicity induced by the antineoplastic platinum complex nedaplatin (NDP) in rats of different ages in comparison with cisplatin (CDDP). A single dose of 15 mg/kg NDP or 7.5 mg/kg CDDP was administered intravenously to 8-, 11-, or 15-week-old male and female SD rats, which were then sacrificed after ten days. Body weight decreases were observed for both drugs, in direct relation to age. CDDP treatment markedly increased urinary excretion of NAG, gamma-GTP, LDH and protein, with peaks on day 4 and complete or partial recovery on day 7; NDP increased NAG, LDH and protein excretion, but to a lesser extent, and these elevations were generally more marked for females. CDDP increased plasma creatinine and BUN in males and females of all age groups at necropsy. No apparent changes were seen following NDP treatment except in the 15-week-old rats. These results also show that NDP is less nephrotoxic than CDDP. CDDP-treated rats showed remarkable proximal tubular lesions in the renal cortex and corticomedullary region, and the papillary lesions were minor. On the other hand, the NDP-induced nephrotoxicity was morphologically characterized by hyaline droplet changes (electron microscopically, hyperplasia of lysosomes), necrosis or hyperplasia of the collecting duct epithelium in the renal papilla and the epithelium covering the papilla. Cortical lesions, indicated by slight tubular dilatation, were found only in the animals with papillary lesions. In summary, NDP is a promising second-generation platinum complex with reduced nephrotoxicity.

Virtual screening of novel noncovalent inhibitors for SARS-CoV 3C-like proteinase

The SARS coronavirus 3C-like proteinase is considered as a potential drug design target for the treatment of severe acute respiratory syndrome (SARS). Owing to the lack of available drugs for the treatment of SARS, the discovery of inhibitors for SARS coronavirus 3C-like proteinase that can potentially be optimized as drugs appears to be highly desirable. We have built a "flexible" three-dimensional model for SARS 3C-like proteinase by homology modeling and multicanonical molecular dynamics method and used the model for virtual screening of chemical databases. After Dock procedures, strategies including pharmocophore model, consensus scoring, and "drug-like" filters were applied in order to accelerate the process and improve the success rate of virtual docking screening hit lists. Forty compounds were purchased and tested by HPLC and colorimetric assay against SARS 3C-like proteinase. Three of them including calmidazolium, a well-known antagonist of calmodulin, were found to inhibit the enzyme with an apparent K(i) from 61 to 178 microM. These active compounds and their binding modes provide useful information for understanding the binding sites and for further selective drug design against SARS and other coronavirus.

A Phase I and pharmacological study with imidazolium-trans-DMSO-imidazole-tetrachlororuthenate, a novel ruthenium anticancer agent

PURPOSE

NAMI-A [H(2)Im[trans-RuCl(4)(DMSO)HIm] or imidazolium-trans-DMSO-imidazole-tetrachlororuthenate] is a novel ruthenium-containing compound that has demonstrated antimetastatic activity in preclinical studies. This Phase I study was designed to determine the maximum-tolerated dose (MTD), profile of adverse events, and dose-limiting toxicity of NAMI-A in patients with solid tumors. Furthermore, the ruthenium pharmacokinetics (PK) after NAMI-A administration and preliminary antitumor activity were evaluated.

PATIENTS AND METHODS

Adult patients with solid tumors received NAMI-A as an i.v. infusion over 3 h daily for 5 days every 3 weeks. PK of total and unbound ruthenium was determined during the first and second treatment using noncompartmental pharmacokinetic analysis. The total accumulation of ruthenium in WBCs was also quantified.

RESULTS

Twenty-four patients were treated at 12 dose levels (2.4-500 mg/m(2)/day). At 400 mg/m(2)/day, blisters developed on the hands, fingers, and toes. At 500 mg/m(2)/day, blisters persisted from weeks to months and slowly regressed. Although no formal common toxicity criteria (CTC) grade 3 developed, painful blister formation was considered dose limiting. Because the first signs developed at 400 mg/m(2)/day, the advised dose for further testing of NAMI-A was determined to be 300 mg/m(2)/day on this schedule. PK analysis revealed a linear relationship between dose and area under the concentration-time curve (AUC) of total and unbound ruthenium (R(2) = 0.75 and 0.96, respectively) over the whole dose range. Plasma clearance of total ruthenium was 0.17 +/- 0.09 liter/h, and terminal half-life was 50 +/- 19 h. The volume of distribution at steady state of total ruthenium was 10.1 +/- 2.8 liters. The accumulation of ruthenium in WBC was not directly proportional to the increasing total exposure to ruthenium. One patient with pretreated and progressive nonsmall cell lung cancer had stable disease for 21 weeks.

CONCLUSION

NAMI-A can be administered safely as a 3-h i.v. infusion at a dose of 300 mg/m(2)/day for 5 days, every 3 weeks.

Molecular mechanisms of heptaplatin effective against cisplatin-resistant cancer cell lines: less involvement of metallothionein

Background

Heptaplatin is a new platinum derivative with anticancer activity against various cancer cell lines, including cisplatin-resistant cancer cell lines (Cancer Chemother Pharmacol 1995; 35: 441).

Methods

Molecular mechanisms of heptaplatin effective against cisplatin-resistant cancer cell lines has been investigated in connection with metallothionein (MT). Cytotoxicity was determined by an MTT assay. MT mRNA, was determined by RT-PCR assay. Transfection study was carried out to examine the function of MT.

Results

Of various gastric cancer cell lines, SNU-638 and SNU-601 showed the highest and lowest levels of MT mRNA, respectively, showing 80-fold difference. The IC₅₀ values of SNU-638 to cisplatin, carboplatin and heptaplatin were 11.2-fold, 5.1-fold and 2.0-fold greater than those of SNU-601, respectively. Heptaplatin was more effective against cisplatin-resistant and MT-transfected gastric cancer sublines than cisplatin or carboplatin was. In addition, heptaplatin attenuated cadmium, but not zinc, induction of MT.

Conclusion

These results indicate that molecular mechanisms of heptaplatin effective against cisplatin-resistant gastric cancer sublines is at least in part due to the less involvement of MT in heptaplatin resistance as well as its attenuation of MT induction.

Platinum Compound-Related Ototoxicity in Children: Long-Term Follow-Up Reveals Continuous Worsening of Hearing Loss

OBJECTIVES

The purpose of this study was to evaluate the severity of hearing loss after cisplatin and/or carboplatin treatment in young children and to analyze its evolution and its relation to different therapy schedules.

METHODS

One hundred twenty patients treated in the Pediatrics Department at the Institut Gustave-Roussy from 1987 to 1997 for neuroblastoma, osteosarcoma, hepatoblastoma, or germ cell tumors were analyzed. Median age at diagnosis was 2.6 (range 0-17) years. Median follow-up was 7 (1-13) years. Chemotherapy regimens contained cisplatin and/or carboplatin. Three patients also received high-dose carboplatin. Cisplatin was administered at a dose of 200 mg/m/course in 72% of cases. The median cumulative dose was 400 mg/m for cisplatin and 1,600 mg/m for carboplatin. Hearing loss of grade 2 or above, according to Brock's grading scale, was revealed with pure tone audiometry and behavioral techniques.

RESULTS

Carboplatin alone was not ototoxic. Deterioration of hearing of grade 2 or above was observed in 37% of patients treated with cisplatin and 43% of patients treated with cisplatin plus carboplatin (P = NS). Fifteen percent of patients experienced grade 3 or 4 ototoxicity. Ototoxicity was most often observed after a total cisplatin dose of at least 400 mg/m. No improvement was observed with time; on the contrary, worsening or progression of hearing loss at lower frequencies was detected during follow-up. Only 5% of audiograms showed toxicity of at least grade 2 before the end of therapy; in contrast, this level was observed in 11% of early post-therapy evaluations and in 44% after more than 2 years of follow-up.

CONCLUSIONS

Children treated with cisplatin at cumulative doses approaching 400 mg/m require long-term surveillance to avoid overlooking hearing deficits. Carboplatin, at a standard dose, does not appear to be a significant risk factor for ototoxicity even in patients who have already been treated with cisplatin.

Carboplatin-induced oxidative injury in rat inferior colliculus

Carboplatin is currently being used as an anticancer drug against human cancers. However, high dose of carboplatin chemotherapy resulted in ototoxicity in cancer patients. Carboplatin-induced ototoxicity was related to oxidative stress to the cochlea and inner hair cell loss in animals. It is likely that initial oxidative injury spreads throughout the neuroaxis of the auditory system later. The study aim was to evaluate carboplatin-induced hearing loss and oxidative injury to the central auditory system (inferior colliculus) of the rat. Male Wistar rats were divided into two groups of seven animals each and treated as follows: (1) control (normal saline, intraperitoneal [i.p.]) and (2) carboplatin (256 mg/kg, i.p.). Auditory brain-evoked responses (ABRs) were recorded before and 4 days after treatments. The animals were sacrificed on the 4th day and inferior colliculus from brain stem and cerebellum were isolated and analyzed. Carboplatin significantly elevated the hearing threshold shifts at clicks, 2-, 4-, 8-, 16-, and 32-kHz tone burst stimuli. Carboplatin significantly increased nitric oxide and lipid peroxidation, xanthine oxidase, and manganese superoxide dismutase activities in the inferior colliculus, but not in the cerebellum, indicating an enhanced flux of free radicals in the central auditory system. Carboplatin significantly depressed the reduced to oxidized glutathione ratio, antioxidant enzyme activities, such as copper-zinc superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase, and enzyme protein expressions in the inferior colliculus, but not in the cerebellum, 4 days after treatment. The data suggest that carboplatin induced oxidative injury specifically in the inferior colliculus of the rat leading to hearing loss.

Basic treatment considerations: chemotherapy

Lung cancer represents a major global health problem, with more than a million deaths reported each year. Because there are no effective screening tools to date, diagnosis of the disease at an advanced stage is a common feature. Over the past 20 years, elegant strides have been made in the treatment of patients with advanced NSCLC. Several novel chemotherapy agents that are efficacious and possess favorable toxicity profiles have been developed recently. In addition to evaluating novel combinations, alternative schedules to improve toxicity profiles are subjects of clinical trials. Much work needs to be done, however, to improve the outcome for patients with lung cancer. Chemotherapy extends life and improves quality of life for patients with stage IIIB/IV NSCLC. Combined modality therapy with radiation and chemotherapy improves the outcome for patients with locally advanced NSCLC and is associated with a curative potential. Molecularly targeted therapies are under rigorous evaluation, although the initial results have been disappointing. In the upcoming years, we will learn effective means to incorporate molecularly targeted therapies to existing treatment paradigms in lung cancer.

Expression of caspase-activated deoxyribonuclease (CAD) and caspase 3 (CPP32) in the cochlea of cisplatin (CDDP)-treated guinea pigs

Cisplatin, an anti-cancer drug, is known to induce apoptosis. During apoptosis, double-stranded DNA is broken into single-stranded DNA by the action of caspases and caspase activated deoxyribonuclease (CAD). We immunohistochemically examined the cochlea of guinea pigs for signs of the apoptosis after the administration of cisplatin. Cisplatin (10 mg/kg b.w.) was intraperitoneally injected to guinea pigs and 3 days later, the animals were sacrificed by intracardiac perfusion of 4% paraformaldehyde. The temporal bones were then removed and immunohistochemically stained for CAD and caspase 3, using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labelling method. CAD was observed in the stria vascularis and the spiral ligament. Caspase 3 was also detected in the stria vascularis, the spiral ligament and the supporting cells of the organ of Corti. These findings suggest that apoptosis is involved in the cochlear damage observed in cancer patients treated with cisplatin.

Carboplatin-induced early cochlear lesion in chinchillas

Carboplatin preferentially damages inner hair cells (IHC) and type I spiral ganglion neurons (SGNs) in the chinchilla; however, the temporal sequence of events leading to the destruction of these structures is poorly understood. To better understand the mechanisms leading up to the destruction of IHCs and type I SGNs, we measured the activity in single auditory nerve fibers for the first 8 h following carboplatin treatment and also monitored the development of histopathologies in SGNs and IHCs using a dose of carboplatin that killed approximately 50% of the IHCs. The spontaneous discharge rate (SDR) showed a slight increase around 3 h post carboplatin followed by a significant decline at 4-5 h. The saturation driven discharge rate (DDR) showed a significant increase 1-5 h post carboplatin. These physiological changes were associated with the formation of small vacuoles in type I afferent terminals and proximal nerve fibers 1-6 h post carboplatin; signs of IHC damage were first observed around 24-48 h. Thus, the neurotoxic effects of carboplatin occur approximately a day before the IHCs are damaged. The large fluctuations in SDR and DDR that occur several hours after carboplatin treatment are most likely due to the neurotoxic effects of carboplatin.

Toxicity of platinum compounds

Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

Platinum drugs in the treatment of non-small-cell lung cancer

The use of chemotherapy is considered standard therapy in patients with locally advanced non-small-cell lung cancer that cannot be treated with radiotherapy and in those with metastatic non-small-cell lung cancer and good performance status. This approach is also accepted in patients with earlier stage disease, when combined with radiotherapy in those with non-resectable locally advanced disease, or in the preoperative setting. Randomised clinical studies and meta-analyses of the literature have confirmed the beneficial survival effect of platinum-based chemotherapy. Cisplatin and carboplatin have been successfully used with other drugs in a wide variety of well-established two-drug combinations while three-drug combinations are still under investigation. Cisplatin and carboplatin use is limited by toxicity and inherent resistance. These considerations have prompted research into new platinum agents, such as the trinuclear platinum agent BBR3464, the platinum complex ZD0473 and oxaliplatin. These compounds could be developed in combination with agents such as paclitaxel, gemcitabine or vinorelbine in patients with advanced and/or refractory solid tumours.