Bleomycin pharmacokinetics in man. I. Intravenous administration

In Vitro to In Vivo Concordance of Toxicity Using the Human Proximal Tubule Cell Line HK-2

The renal proximal tubule cell line, human kidney 2 (HK-2), recapitulates many of the functional cellular and molecular characteristics of differentiated primary proximal tubule cells. These features include anchorage dependence, gluconeogenesis capability, and sodium-dependent sugar transport. In order to ascertain how well HK-2 cells can reliably reveal the toxicological profile of compounds having a potential to cause proximal tubule injury in vivo, we sought to evaluate the effects of known proximal tubule toxicants using the HK-2 cell line. We selected 20 pure nephrotoxic compounds that included chemotherapeutic drugs, antibiotics, and heavy metal-containing compounds and evaluated their ability to induce HK-2 cell injury relative to 10 innocuous pure compounds or cell culture media alone. We performed a comprehensive set of in vitro cellular toxicological assays to evaluate cell viability, oxidative stress, mitochondrial integrity, and a specific biomarker of renal injury, Kidney Injury Molecule 1. For each of our selected compounds, we were able to establish a reproducible profile of toxicological outcomes. We compared our results to those described in peer-reviewed publications to understand how well the HK-2 cellular model agrees with overall in vivo rat or human toxicological outcomes. This study begins to address the question of how well in vitro data generated with HK-2 cells can mirror in vivo animal and human outcomes.

Electrochemotherapy of superficial tumors - Current status:: Basic principles, operating procedures, shared indications, and emerging applications

Treatment of superficial tumors with electrochemotherapy (ECT) has shown a steep rise over the past decade and indications range from skin cancers to locally advanced or metastatic neoplasms. Based on reversible electroporation, which is a physical method to achieve transient tumor cell membrane permeabilization by means of short electric pulses, ECT increases cellular uptake of bleomycin and cisplatin and their cytotoxicity by 8,000- and 80-fold, respectively. Standard operating procedures were established in 2006 and updated in 2018. Ease of administration, patient tolerability, efficacy across histotypes, and repeatability are peculiar advantages, which make standard ECT (ie, ECT using fixed-geometry electrodes) a reliable option for controlling superficial tumor growth locally and preventing their morbidity. Consolidated indications include superficial metastatic melanoma, breast cancer, head and neck skin tumors, nonmelanoma skin cancers, and Kaposi sarcoma. In well-selected patients with oropharyngeal cancers, ECT ensures appreciable symptom control. Emerging applications include skin metastases from visceral or hematological malignancies, vulvar cancer, and some noncancerous skin lesions (keloids and capillary vascular malformations). Repeatability and integration with other oncologic therapies allow for consolidation of response and sustained tumor control. In this review, we present the basic principles of ECT, recently updated operating procedures, anesthesiological management, and provide a synthesis of the efficacy of standard ECT across histotypes.

The Interaction of the Metallo-Glycopeptide Anti-Tumour Drug Bleomycin with DNA

The cancer chemotherapeutic drug, bleomycin, is clinically used to treat several neoplasms including testicular and ovarian cancers. Bleomycin is a metallo-glycopeptide antibiotic that requires a transition metal ion, usually Fe(II), for activity. In this review, the properties of bleomycin are examined, especially the interaction of bleomycin with DNA. A Fe(II)-bleomycin complex is capable of DNA cleavage and this process is thought to be the major determinant for the cytotoxicity of bleomycin. The DNA sequence specificity of bleomycin cleavage is found to at 5′-GT* and 5′-GC* dinucleotides (where * indicates the cleaved nucleotide). Using next-generation DNA sequencing, over 200 million double-strand breaks were analysed, and an expanded bleomycin sequence specificity was found to be 5′-RTGT*AY (where R is G or A and Y is T or C) in cellular DNA and 5′-TGT*AT in purified DNA. The different environment of cellular DNA compared to purified DNA was proposed to be responsible for the difference. A number of bleomycin analogues have been examined and their interaction with DNA is also discussed. In particular, the production of bleomycin analogues via genetic manipulation of the modular non-ribosomal peptide synthetases and polyketide synthases in the bleomycin gene cluster is reviewed. The prospects for the synthesis of bleomycin analogues with increased effectiveness as cancer chemotherapeutic agents is also explored.

Electrochemotherapy of unresectable cutaneous tumours with reduced dosages of intravenous bleomycin: analysis of 57 patients from the International Network for Sharing Practices of Electrochemotherapy registry

BACKGROUND

Electrochemotherapy (ECT) is currently used to treat unresectable superficial tumours of different histotypes through the combination of cytotoxic chemotherapy and local application of electric pulses. In 2006, a collaborative project defined the ESOPE (European Standard Operating Procedures of Electrochemotherapy) guidelines to standardize the procedure. The International Network for Sharing Practices of Electrochemotherapy (InspECT) aims to refine the ESOPE and improve clinical practice. Limiting patient exposure to systemic chemotherapy would be advisable to ameliorate ECT safety profile.

OBJECTIVE

The aim of this study was to evaluate the efficacy and toxicity of ECT with reduced chemotherapy dosages.

METHODS

In a retrospective analysis of a prospectively maintained database (InspECT registry), we evaluated the outcome of patients who received ECT with reduced dosages of bleomycin (7500, 10 000 or 13 500 IU/m² , instead of the standard dose of 15 000 IU/m² ). Tumour response in melanoma patients was compared with melanoma patients of the InspECT registry who received the standard dose of bleomycin.

RESULTS

We identified 57 patients with 147 tumours (melanoma, 38.6%; squamous cell carcinoma, 22.8%; basal cell carcinoma, 17.5%; breast cancer 7%; Kaposi sarcoma 7%; other histotypes, 7.1%). Per-tumour complete response (CR) rate at 60 days was 70.1% (partial, 16.3%); per-patient CR was 57.9% (partial, 21.1%). Local pain was the most frequently reported side-effect (n = 22 patients [39%]), mostly mild; two patients experienced flu-like symptoms, one patient nausea. We observed the same CR rate (55%) in patients with melanoma treated by reduced or conventional bleomycin dosages (P = 1.00).

CONCLUSIONS

Electrochemotherapy performed with reduced bleomycin dosages could be as effective as with currently recommended dose. Patients with impaired renal function or candidate to multiple ECT cycles could benefit from a reduced dose protocol. Our findings need prospective confirmation before being adopted in clinical practice.

Safety and efficacy of bleomycin/pingyangmycin-containing chemotherapy regimens for malignant germ cell tumor patients in the female genital system

OBJECTIVES

To comprehensively evaluate the safety and effectiveness of bleomycin/pingyangmycin-containing chemotherapy for female patients with malignant germ cell tumors in their genital system; to assess the diagnostic value of pulmonary function tests for bleomycin-induced pulmonary toxicity.

METHODS

Data from a cohort of 120 patients, collected across 25 years, was reviewed. Chemotherapy-related adverse events were routinely monitored. Pulmonary toxicity was diagnosed and graded according to serial pulmonary function testing results, and potential impact factors were explored. Short-term remission probability and long-term prognosis were evaluated.

RESULTS

Overall, 49.2% of the patients had pulmonary dysfunction, and the majority manifested as diffusion function impairment. A moderate reduction of carbon monoxide diffusion capacity was detected in 45.0% of all patients, and was severe in 3 patients. Thrombocytopenia, renal dysfunction, and accumulating dose of bleomycin/pingyangmycin significantly increased the risk of lung injury (P<0.05). Thorough surgical removal of tumors enhanced both remission and survival rate. Full-dose delivery of bleomycin/pingyangmycin and patients' sensitivity to chemotherapy also improved long-term survival (P<0.05).

CONCLUSIONS

BPT could be sensitively detected and elaborately graded by PFTs, but the appropriate cut-off value for diagnosis needs further investigations. Timely recognition and control of renal dysfunction and thrombocytopenia could avail the patients of the opportunity to complete curative antineopalstic treatment. Prescriptive bleomycin/pingyangmycin-containing chemotherapy after optimal surgical resection could benefit MGCT patients maximally by improving both remission and survival rate.

[Consortium for detection and management of lung damage induced by bleomycin]

Bleomycin is a cytotoxic antibiotic and a component of chemotherapy regimens of germ cell tumors and lymphoma. Bleomycin lung injuries occur in 10% of patients, and lead to severe interstitial pneumonia in 3% of patients. Pulmonary toxicity is related to endothelial cells injury induce by free radicals and inflammatory cytokines. Diagnosis of bleomycin-induced lung toxicity is based on the combination of clinical and radiological features, and requires to rule out differential diagnoses including pneumocystis. "Bleomycin-induced pneumonitis" is the most frequent pattern; eosinophilic pneumonitis and organizing pneumonia are rarer. Occurrence of bleomycin lung toxicity requires an immediate and often permanent discontinuation. Treatment is based on steroid. Regular clinical and pulmonary function tests monitoring are mandatory for early detection of bleomycin-induced lung toxicity.

Growth differentiation factor 15 (GDF-15) plasma levels increase during bleomycin- and cisplatin-based treatment of testicular cancer patients and relate to endothelial damage

Introduction

Chemotherapy-related endothelial damage contributes to the early development of cardiovascular morbidity in testicular cancer patients. We aimed to identify relevant mechanisms of and search for candidate biomarkers for this endothelial damage.

Methods

Human micro-vascular endothelial cells (HMEC-1) were exposed to bleomycin or cisplatin with untreated samples as control. 18k cDNA microarrays were used. Gene expression differences were analysed at single gene level and in gene sets clustered in biological pathways and validated by qRT-PCR. Protein levels of a candidate biomarker were measured in testicular cancer patient plasma before, during and after bleomycin-etoposide-cisplatin chemotherapy, and related to endothelial damage biomarkers (von Willebrand Factor (vWF), high-sensitivity C-Reactive Protein (hsCRP)).

Results

Microarray data identified several genes with highly differential expression; e.g. Growth Differentiation Factor 15 (GDF-15), Activating Transcription Factor 3 (ATF3) and Amphiregulin (AREG). Pathway analysis revealed strong associations with ‘p53’ and ‘Diabetes Mellitus’ gene sets. Based on known function, we measured GDF-15 protein levels in 41 testicular patients during clinical follow-up. Pre-chemotherapy GDF-15 levels equalled controls. Throughout chemotherapy GDF-15, vWF and hsCRP levels increased, and were correlated at different time-points.

Conclusion

An unbiased approach in a preclinical model revealed genes related to chemotherapy-induced endothelial damage, like GDF-15. The increases in plasma GDF-15 levels in testicular cancer patients during chemotherapy and its association with vWF and hsCRP suggest that GDF-15 is a potentially useful biomarker related to endothelial damage.

Tumor size and effectiveness of electrochemotherapy

BACKGROUND

Electrochemotherapy (ECT) is an effective and safe method for local treatment of tumors. However, relatively large variability in effectiveness of ECT has been observed, which likely results from different treatment conditions and tumor characteristics. The aim of this study was to investigate the relationship between tumor size and effectiveness of a single-session ECT.

MATERIALS AND METHODS

A systematic search of various bibliographic databases was performed and nine studies eligible for this study were extracted. Different statistical methods including meta-analysis were applied to analyze the data.

RESULTS

The results of analysis based on data from 1466 tumors of any histotype show significantly lower effectiveness of ECT on tumors with maximal diameter equal to or larger than 3 cm (complete response (CR) of 33.3%, objective response (OR) of 68.2%) in comparison to smaller tumors (CR% of 59.5%, OR% of 85.7%). The results of meta-analysis indicated that ECT performed on tumors smaller than 3 cm statistically significantly increases the probability of CR by 31.0% and OR by 24.9% on average in comparison to larger tumors. The analysis of raw data about the size and response of tumors showed statistically significant decrease in effectiveness of ECT progressively with increasing tumor diameter. The biggest drop in CR% was detected at tumor diameters as small as 2 cm.

CONCLUSIONS

The standard operating procedures for ECT should be reexamined and refined for the treatment of large tumors. We propose that future clinical trials should include accurate ECT treatment planning and/or multiple ECT cycles, besides a prolonged observation for tumor response evaluation.

Revisiting bleomycin from pathophysiology to safe clinical use

Bleomycin is a key component of curative chemotherapy regimens employed in the treatment of curable cancers, such as Hodgkin lymphoma (HL) and testicular germ-cell tumours (GCT), yet its use may cause bleomycin-induced lung injury (BILI), which is associated with significant morbidity and a mortality rate of 1-3%. Diagnosis of BILI is one of exclusion and physicians involved in the care of HL and GCT patients should be alerted. Pharmacogenomic studies could contribute towards the identification of molecular predictors of bleomycin toxicity on the aim to optimize individual use of bleomycin. We review all existing data on bleomycin's most recent integrated chemical biology, molecular pharmacology and mature clinical data and provide guidelines for its safe clinical use.

Antitumor effectiveness of electrochemotherapy: a systematic review and meta-analysis

BACKGROUND

This systematic review has two purposes: to consolidate the current knowledge about clinical effectiveness of electrochemotherapy, a highly effective local therapy for cutaneous and subcutaneous tumors; and to investigate the differences in effectiveness of electrochemotherapy with respect to tumor type, chemotherapeutic drug, and route of drug administration.

METHODS

All necessary steps for a systematic review were applied: formulation of research question, systematic search of literature, study selection and data extraction using independent screening process, assessment of risk of bias, and statistical data analysis using two-sided common statistical methods and meta-analysis. Studies were eligible for the review if they provided data about effectiveness of single-session electrochemotherapy of cutaneous or subcutaneous tumors in various treatment conditions.

RESULTS

In total, 44 studies involving 1894 tumors were included in the review. Data analysis confirmed that electrochemotherapy had significantly (p < .001) higher effectiveness (by more than 50%) than bleomycin or cisplatin alone. The effectiveness was significantly higher for intratumoral than for intravenous administration of bleomycin (p < .001 for CR%, p = .028 for OR%). Bleomycin and cisplatin administered intratumorally resulted in equal effectiveness of electrochemotherapy. Electrochemotherapy was more effective in sarcoma than in melanoma or carcinoma tumors.

CONCLUSIONS

The results of this review shed new light on effectiveness of electrochemotherapy and can be used for prediction of tumor response to electrochemotherapy with respect to various treatment conditions and should be taken into account for further refinement of electrochemotherapy protocols.

Bleomycin has antiviral properties against drug-resistant HIV strains and sensitises virus to currently used antiviral agents

In this study we performed phenotypic assays to assess involvement of the cancer chemotherapeutic agent bleomycin (BLM) in replication inhibition of mutant HIV-1 viral strains. Three clinically relevant mutant HIV variants, including one containing the Q151M mutation conferring multinucleoside resistance, were equally as sensitive to BLM as the wild-type HXB2 strain. Long-term incubation of BLM with a wild-type HIV(Ba-L) strain did not alter the sensitivity of the strain to BLM (IC(50) of BLM 0.64 microM at the beginning of incubation to 0.58 microM). At the same point in time, resistance to lamivudine (3TC) and zidovudine (AZT) was noted. Interestingly, the BLM-treated virus showed hypersensitivity to both AZT and 3TC. Our results suggest a contribution of BLM in viral load reduction in patients receiving both anticancer and antiviral agents and harbouring both wild-type and resistant HIV strains.

Accurate measurement of individual glomerular filtration rate in cancer patients: an ongoing challenge

A narrow therapeutic index is a characteristic feature of cytotoxic agents. Some of these agents are almost entirely eliminated renally in unchanged active form. As a consequence, assessment of the individual glomerular filtration rate (GFR) may help to predict the pharmacokinetic behaviour of cytotoxic agents in plasma more precisely. In addition, GFR-adapted individualization of cancer chemotherapy may have an enormous impact on the severity of side effects. Several methods are available to determine GFR or creatinine clearance (CrCl). GFR-measurement based on experimental methods with radiolabelled isotopes, contrast media or inulin helps to reflect the real situation very closely. In addition, 24-h urine collection is a convenient and feasible method to measure creatinine clearance. Finally, several mathematical equations exist to estimate GFR or CrCl based on serum creatinine and other parameters. Only a few of these equations have been developed in oncologic patients. However, some of these equations are routinely used in clinical practice, because they allow a rapid estimation of GFR. Based on the fact that clinically relevant differences have been assessed between calculated values and the real situation, mathematical calculation of GFR or CrCl does not seem to be appropriate to assess individual renal function precisely enough over a broad range of individual GFR or CrCl. Whether the measurement of low-molecular-weight proteins, such as cystatin C and ss-trace protein, may help to reflect the real situation more precisely is a matter of controversial debate.

Pharmacokinetic studies in children with cancer

We reviewed the current status of our knowledge of pharmacokinetics and pharmacodynamics of some anti-neoplastic drugs, used in the treatment of childhood cancer. Extrapolation of data from pharmacokinetic studies in adults to the paediatric population is often not feasible. Specific studies in children are needed. Of all reviewed anti-neoplastic drugs methotrexate appears to be most extensively studied. Methotrexate pharmacokinetics is correlated with toxicity and response to therapy, and it has been shown that individualized adaptive dosing of methotrexate is correlated with a better response to therapy without increasing toxicity in children with ALL and osteosarcoma. Of most of the other reviewed anti-neoplastic drugs it is demonstrated that pharmacokinetics is correlated with toxicity, and of some drugs a relationship of pharmacokinetics with response to therapy is demonstrated as well. In case of cytarabine, etoposide, and teniposide, individualized dosing also appears to be feasible. However, there is no evidence that this strategy improves response to therapy. Specifically data on pharmacokinetic and pharmacodynamic correlations and effect of pharmacokinetically guided, individualized dosing are important for the design of optimal cancer chemotherapy for individual patients. Unfortunately for a considerable number of anti-neoplastic drugs these specific data are lacking in children and future research is needed.

Electrochemotherapy: results of cancer treatment using enhanced delivery of bleomycin by electroporation

Over the last decade a new cancer treatment modality, electrochemotherapy, has emerged. By using short, intense electric pulses that surpass the capacitance of the cell membrane, permeabilization can occur (electroporation). Thus, molecules that are otherwise non-permeant can gain direct access to the cytosol of cells in the treated area.A highly toxic molecule that does not usually pass the membrane barrier is the hydrophilic drug bleomycin. Once inside the cell, bleomycin acts as an enzyme creating single- and double-strand DMA-breaks. The cytotoxicity of bleomycin can be augmented several 100-fold by electroporation. Drug delivery by electroporation has been in experimental use for cancer treatment since 1991. This article reviews 11 studies of electrochemotherapy of malignant cutaneous or subcutaneous lesions, e.g., metastases from melanoma, breast or head- and neck cancer. These studies encompass 96 patients with altogether 411 malignant tumours. Electroporation was performed using plate or needle electrodes under local or general anaesthesia. Bleomycin was administered intratumourally or intravenously prior to delivery of electric pulses. The rates of complete response (CR) after once-only treatments were between 9 and 100% depending on the technique used. The treatment was well tolerated and could be performed on an out-patient basis.

The chemotherapeutic agent bleomycin in a two-drug combination with zidovudine, ritonavir or indinavir synergistically inhibits HIV Type-1 replication in peripheral blood lymphocytes

It has been suggested that the combination of cancer chemotherapy with antiviral therapy is helpful for the containment of lymphomas in HIV-infected patients. Since we have recently shown that the nucleic acid binding chemotherapeutic agent bleomycin in itself has antiviral properties, we looked to see if there was any possible synergy with current anti-HIV agents. Combinations of zidovudine, indinavir or ritonavir with bleomycin, synergistically inhibited HIV-1(AT) replication in stimulated peripheral blood lymphocytes (combination index at 50% virus inhibition was 0.427, 0.604 and 0.535, respectively) and this synergism was not accompanied by any synergistic effects on cytotoxicity. We conclude from these data that further studies to investigate the clinical efficacy of combinations of antiviral and cancer chemotherapeutic agents are warranted in relation to viral load improvement.

Mechanisms of bleomycin-induced lung damage

Bleomycins are a family of compounds produced by Streptomyces verticillis. They have potent tumour killing properties which have given them an important place in cancer chemotherapy. They cause little marrow suppression, but pulmonary toxicity is a major adverse effect. The mechanisms of cell toxicity are well described based on in vitro experiments on DNA. The bleomycin molecule has two main structural components: a bithiazole component which partially intercalates into the DNA helix, parting the strands, as well as pyrimidine and imidazole structures, which bind iron and oxygen forming an activated complex capable of releasing damaging oxidants in close proximity to the polynucleotide chains of DNA. This may lead to chain scission or structural modifications leading to release of free bases or their propenal derivatives. The mechanisms are well described based on in vitro experiments on DNA, but how they relate to intact cells in whole animals is more tenuous. Bleomycin is able to cause cell damage independent from its effect on DNA by induction lipid peroxidation. This may be particularly important in the lung and in part account for its ability to cause alveolar cell damage and subsequent pulmonary inflammation. The lung injury seen following bleomycin comprises an interstitial oedema with an influx of inflammatory and immune cells. This may lead to the development of pulmonary fibrosis, characterized by enhanced production and deposition of collagen and other matrix components. Several polypeptide mediators capable of stimulating fibroblasts replication or excessive collagen deposition have been implicated in this, but the precise role of these in bleomycin-induced fibrosis is yet to be demonstrated. Current therapy for bleomycin-induced lung damage is inadequate, with corticosteroids most often used. Given the mechanism of action described above, antioxidants and iron chelators might be beneficial. Although, studies to date are equivocal and there is insufficient evidence to promote their use clinically. Novel drugs are currently being developed and it is hoped these may be more useful.

Validation of clinical predictive value of in vitro colorimetric chemosensitivity assay in head and neck cancer

For chemosensitivity testing, a rapid in vitro colorimetric method (MTT assay) was used. Eleven head and neck cancer cell lines were investigated to distinguish five known active agents from five compounds inactive in phase II studies. Evaluation of the reliability of the assay for assessing drug sensitivity in this tumor cell population was done by correlating the in vitro results with reported in vivo response data. Methotrexate and cisplatin (clinically active) and vindesine and doxorubicin (less active clinically) were recognized in vitro as active and correlated well with clinical experience. Bleomycin (clinically active) was ineffective against some cell lines. The in vitro findings for the clinically inactive drugs (deoxyazacytidine, lomustine, and carmustine) also corresponded. Amsacrine and etoposide, contrary to clinical experience, showed activity in vitro. Further comparison of MTT assay results with clinical data is warranted and essential before its use in large-scale drug screening studies.

Clinical management of cytotoxic drug overdose

In this article the pharmacological management of accidental drug overdose is discussed, with various treatments for overdose proposed, as supported by clinical facts and speculation. Current knowledge is outlined concerning dacarbazine, nitrosourea compounds, melphalan, procarbazine, cyclophosphamide, VP-16.213, l-asparaginase (colaspase), 6-mercaptopurine, mustine (nitrogen mustard), intravenous or intrathecal methotrexate (amethopterin), cytarabine (cytosine arabinoside), fluorouracil and bleomycin.

Development of acute lung injury after the combination of intravenous bleomycin and exposure to hyperoxia in rats

Pulmonary toxicity is an important adverse effect of bleomycin treatment. Very little is known of the mechanisms underlying the development of lung injury, especially after intravenous administration, or how it can be modulated. In this study acute lung injury induced by bleomycin has been examined in rats by assessment of alveolar lavage cell profiles, histological examination, and measurement of the total pulmonary extravascular albumin space. Intratracheal instillation of bleomycin 1.5 mg resulted in a severe pneumonitis with influx of inflammatory cells into the alveoli as assessed by alveolar lavage, oedema of the alveolar walls, and up to an eight fold increase in the total pulmonary extravascular albumin space, maximal at 72 hours. Intravenous bleomycin 0.15-5 mg produced no detectable injury when assessed in these ways. Exposure to hyperoxia (40-90%) after intravenous bleomycin, however, induced lung injury similar to that produced by intratracheal bleomycin. A much more severe injury followed administration of intravenous bleomycin after an exposure to hyperoxia, which itself resulted in lung injury; but lung injury was still detectable after bleomycin when the exposure to hyperoxia was insufficient to induce changes in control animals. Lung injury was not observed when the exposure to hyperoxia preceded bleomycin treatment. These results indicate the importance of oxygen in the pathways leading to acute lung injury following intravenous bleomycin. We conclude that exposure to oxygen might induce lung injury during and after bleomycin treatment, and suggest that in these circumstances oxygen therapy should be kept to a minimum.

Targeted drug delivery

Cancer chemotherapy drugs are neither specific, i.e., they do not act exclusively on the metabolic pathways of cancer cells, nor are they targeted solely toward cancer cells. However, recent research has begun to address, in part, the latter issue. Improved delivery of chemotherapeutic agents to tumor tissue in man appears to be an achievable goal in the next decade. Improved drug delivery includes developing predictive models that allow for laboratory assessment of the best treatment for a patient's cancer without exposing the patient to an empirical trial or to the possible morbidity from exposure to a less useful drug, or to the loss of time in the fight against cancer because of ineffectual therapy. Monoclonal antibodies directed against tumor-associated antigens have the potential to achieve major advances in targeted drug delivery. Monoclonal antibodies may have direct antitumor effects, or they can be used as "homing devices" when attached to a payload and can guide diagnostic or therapeutic agents to the targeted tissues. Carrier systems of all types have become available; these include liposomes and polymeric compounds which can carry drugs, radionuclides, toxins, or other materials in a protected environment. These carriers can also be bound to monoclonal antibodies for possible targeted delivery. Pharmacological sanctuaries have been recognized as a problem in cancer treatment. The best known of these is the central nervous system (CNS). Techniques to temporarily disrupt the blood-brain barrier are now appearing. Mechanisms to administer therapy directly into the CNS are also being reassessed. Implantable pumps and reservoirs have been used to treat selected organs or for regional perfusions. Other treatments that are regional in scope include administration directly into a cavity or into a tumor. Computerized implantable devices should play a major role in cancer therapy in the future, in pain control as well as antibiotic and hormone administration. In recent years, mathematical models have been developed that can more accurately predict drug distribution and metabolism in various tissues of the body. Such models point the way to more logical designs of chemotherapeutic administration. The expanded use of autologous bone marrow transplantation, along with improving techniques of "purging" the marrow of tumor cells before reinfusion can be anticipated. Pro-drugs are substances that must be biotransformed in vivo to exert their pharmacologic effect.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of the cytotoxic activities of chemotherapeutic drugs using a human bladder cancer cell line

Many chemotherapeutic drugs have been used to treat patients with advanced bladder cancer, but few of these have been evaluated adequately in phase II clinical trials. Continuous cell lines provide one means for comparing the in vitro cytotoxicities of anticancer agents. In this study, a continuous cell line derived from a transitional cell cancer of the human bladder, which still produces tumours histologically similar to the tumour of origin on xenotransplantation, was used to measure the in vitro cytotoxicities of twelve chemotherapeutic drugs by clonogenic assay. The most cytotoxic agents tested were methotrexate, mitoxantrone, adriamycin, mitomycin C and cisplatin. These in vitro findings are compatible with the activity of these drugs given systemically as single agents in phase II clinical trials in patients with advanced bladder cancer.

Antipyrine metabolism in patients with disseminated testicular cancer and the influence of cytostatic treatment

Antipyrine plasma clearance and rates of metabolite formation were measured on four occasions in eight patients with disseminated nonseminomatous testicular cancer. Antipyrine tests were performed before, during (2X), and after treatment with a combination of cisplatin (P), vinblastin (V), and bleomycin (B). Pretreatment values were compared with a male control group (n = 14) matched for age and body weight. Antipyrine plasma clearance was 20% higher in patients with testicular cancer (first experiment) than in the control group. This difference was mainly due to a 35% higher clearance for production of 3-hydroxymethylantipyrine (HMA), while clearance for production of norantipyrine (NORA) and 4-hydroxyantipyrine (OHA) was not significantly different from the control group. A reduction in CLHMA was observed after complete remission (fourth experiment), indicating that the presence of the tumor may be related to a selective increase of HMA formation. Treatment with the PVB combination resulted in a 30% increase in antipyrine plasma clearance (second and third experiments), whereas the rates of formation of the main metabolites of antipyrine were all increased to the same extent. These accelerating effects of PVB treatment persisted for at least 6 weeks after the start of the last treatment cycle. The data presented in this paper demonstrate that the presence of a testicular tumor and the use of cytostatics can have an accelerating and partially selective effect on oxidative drug-metabolizing enzyme activity in man.

Clinical pharmacology of bleomycin and cisplatin

Bleomycin (Blenoxane) and cisplatin (Platinol) are two anticancer drugs, with activity for head and neck tumors, that were introduced into clinical use in the past ten years. Bleomycin is used primarily in the chemotherapy of squamous cell carcinomas, lymphomas, and testicular carcinoma, while cisplatin possesses significant activity against testicular and ovarian carcinoma, head and neck cancer, bladder cancer, and neuroblastoma. Bleomycin is rapidly excreted renally (terminal phase half-life = 2-4 h), although enzymatic inactivation also occurs in many tissues. Cisplatin is nonenzymatically converted to highly protein bound metabolites, which then undergo renal elimination, but total body clearance occurs much more slowly than with bleomycin (terminal phase half-life = 40-50 h). Both agents have acute and chronic toxicities; the acute toxicities are generally reversible but cause a great deal of patient discomfort, while the chronic toxicities are often irreversible and dose-limiting. For bleomycin, the acute toxicities are mucocutaneous are pyretic; severe nausea and vomiting represents the major acute toxicity of cisplatin therapy. Cumulative dose-related pulmonary toxicity is the most serious chronic toxicity of bleomycin. The clinical, radiographic, and pathologic presentations are nonspecific, although identification of high risk patients may be possible with serial pulmonary function tests. Cumulative nephrotoxicity occurs with cisplatin use, and its incidence and severity can be reduced by maintaining adequate hydration and diuresis during and following administration of the drug.

Clinical pharmacology of bleomycin and cisplatin

Bleomycin (Blenoxane) and cisplatin (Platinol) are two anticancer drugs with activity for head and neck tumors. Introduced into clinical use in the past ten years, bleomycin is used primarily in the chemotherapy of squamous cell carcinomas, lymphomas, and testicular carcinoma, while cisplatin is effective against testicular and ovarian carcinoma, head and neck cancer, bladder cancer, and neuroblastoma. Bleomycin is rapidly excreted renally (T 1/2 beta = 2-4 hr) although enzymatic inactivation also occurs in many tissues. Cisplatin is nonenzymatically converted to highly protein-bound metabolites, which then undergo renal elimination, but total body clearance occurs much more slowly than with bleomycin (T 1/2 beta = 40-50 hr). Both agents have acute and chronic toxicities; the acute toxicities are generally reversible but cause a great deal of patient discomfort, while the chronic toxicities are often irreversible and dose-limiting. For bleomycin, the acute toxicities are mucocutaneous and pyretic, while severe nausea and vomiting represent the major acute toxicities of cisplatin therapy. Cumulative dose-related pulmonary toxicity is the most serious chronic toxicity of bleomycin. The clinical, radiographic, and pathologic presentations are nonspecific, although identification of high-risk patients may be possible with serial pulmonary function tests. Cumulative nephrotoxicity occurs with cisplatin use and its incidence and severity can be reduced by maintaining adequate hydration and diuresis during and following administration of the drug.

Antitumour activity and plasma kinetics of bleomycin by continuous and intermittent administration

We have studied the cytotoxicity of bleomycin (4--10 u/kg/day for 6 days) given by continuous i.p. infusion (using an osmotic minipump) compared to daily i.p. bolus administration, against P388 leukaemic spleen colony-forming-units(LCFU-S). Continuous i.p. bleomycin at 8 u/kg/day caused a 0.5 log greater reduction of LCFU-S than did an identical dose given by intermittent bolus administration. The infusion minipump provided constant bleomycin plasma levels of 0.62 +/- 0.03 mu/ml and a total plasma AUC (area under the plasma decay curve) of 89.0 mu.h/ml for 6 days at 8 u/kg/day. Intermittent bolus bleomycin at 8 u.kg/day had a terminal-phase plasma t1/2 of 15 min and a total 6-day plasma AUC of 90.8mu.h/ml. These pharmacokinetic data validate the osmotic minipump as a constant drug-delivery system, and suggest that the two administration schedules resulted in equal total bleomycin dosages. Although high peak bleomycin plasma levels (i.e. 32 mu/ml) were achieved with the intermittent bolus administration, continuous-infusion bleomycin's greater inhibition of LCFU-S was probably related to the drug's schedule-dependent cell-killing characteristics. The results of this study provide further rationale for the continuing use of infusion bleomycin schedules in cancer patients.