Bleomycin and brain tumors. A review

Photochemical internalization of bleomycin for glioma treatment

We study the use of photochemical internalization (PCI) for enhancing chemotherapeutic response to malignant glioma cells in vitro. Two models are studied: monolayers consisting of F98 rat glioma cells and human glioma spheroids established from biopsy-derived glioma cells. In both cases, the cytotoxicity of aluminum phthalocyanine disulfonate (AlPcS2a)-based PCI of bleomycin was compared to AlPcS(2a)-photodynamic therapy (PDT) and chemotherapy alone. Monolayers and spheroids were incubated with AlPcS(2a) (PDT effect), bleomycin (chemotherapy effect), or AlPcS(2a)+bleomycin (PCI effect) and were illuminated (670 nm). Toxicity was evaluated using colony formation assays or spheroid growth kinetics. F98 cells in monolayer/spheroids were not particularly sensitive to the effects of low radiant exposure (1.5  J/cm(2) @ 5 mW/cm(2)) AlPcS(2a)-PDT. Bleomycin was moderately toxic to F98 cells in monolayer at relatively low concentrations-incubation of F98 cells in 0.1 μg/ml for 4 h resulted in 80% survival, but less toxic in human glioma spheroids respectively. In both in vitro systems investigated, a significant PCI effect is seen. PCI using 1.5 J/cm(2) together with 0.25 μg/ml bleomycin resulted in approximately 20% and 18% survival of F98 rat glioma cells and human glioma spheroids, respectively. These results show that AlPcS(2a)-mediated PCI can be used to enhance the efficacy of chemotherapeutic agents such as bleomycin in malignant gliomas.

Medulloblastoma in childhood: revisiting intrathecal therapy in infants and children

INTRODUCTION

Intrathecal chemotherapy is being explored in medulloblastoma in pre-school children as part of brain-sparing strategies and as an alternative to unacceptably neurotoxic cranio-spinal radiotherapy. The range of drugs suitable for this route of administration is restricted by the lack of research evidence of pharmacological suitability and efficacy of other drugs in medulloblastoma.

METHODS

Ideal clinical, biological, physicochemical and pharmaceutical properties for intrathecal administration were defined through literature review of pharmaceutical texts, Medline, Embase and consulting the manufacturers. A total of 126 chemotherapy agents were assessed against these criteria by searching the academic domain of pharmaceutical texts, computer databases and consultation with manufacturers.

RESULTS

Of the 126 candidate drugs, 99 were rejected because of documentation of their irritant nature, neurotoxicity and requirement for hepatic activation in standard pharmaceutical texts. Fifty were rejected for a single identifiable reason including, neurotoxicity (n = 24), irritant (n = 15), needs enzyme activation (n = 5), clinical evidence of intrathecal neurotoxicity (n = 4) and no evidence of tumour-specific efficacy (n = 2). Where two reasons were cited the justifications were: neurotoxic and irritant (n = 3) and needs activation and systemic administration results in equivalent concentration (n = 1). Twenty-seven drugs remained of which 12 were selected as eligible for further clinical investigation, and 15 were selected for further pre-clinical investigation.

CONCLUSIONS

The pre-determined criteria were not applicable, in their entirety, in the majority of drugs, due to lack of information in the academic domain, emphasising the importance of a more open approach for sharing basic drug information. The prioritised list of 12 candidate drugs for clinical trial and 15 for pre-clinical investigation justify that a concerted research effort in this area of practice is made.

Accidental intrathecal administration of bleomycin: favorable outcome after pneumo-encephalus and cerebrospinal fluid exchange: a case report

Bleomycin is generally used as an antineoplastic drug for the intravenous treatment of germ cell tumors or lymphomas. Due to its toxic effect on epithelial cells bleomycin is also used for the treatment of malignant pleural or pericardial effusions. Inadvertent intrathecal administration of cytotoxic drugs may occur due to increasingly complex therapeutic protocols, even when control mechanisms are applied. We report the case of a 39-year-old man with chronic myeloid leukemia. During the treatment of a lymphoblast crisis 30 mg of bleomycin were inadvertently injected intrathecally. Prompt cerebrospinal fluid exchange, dilution with normal saline, and corticosteroid treatment resulted in a positive outcome without major side effects.

Getting into the brain: approaches to enhance brain drug delivery

Being the most delicate organ of the body, the brain is protected against potentially toxic substances by the blood-brain barrier (BBB), which restricts the entry of most pharmaceuticals into the brain. The developmental process for new drugs for the treatment of CNS disorders has not kept pace with progress in molecular neurosciences because most of the new drugs discovered are unable to cross the BBB. The clinical failure of CNS drug delivery may be attributed largely to a lack of appropriate drug delivery systems. Localized and controlled delivery of drugs at their desired site of action is preferred because it reduces toxicity and increases treatment efficiency. The present review provides an insight into some of the recent advances made in the field of brain drug delivery.The various strategies that have been explored to increase drug delivery into the brain include (i) chemical delivery systems, such as lipid-mediated transport, the prodrug approach and the lock-in system; (ii) biological delivery systems, in which pharmaceuticals are re-engineered to cross the BBB via specific endogenous transporters localized within the brain capillary endothelium; (iii) disruption of the BBB, for example by modification of tight junctions, which causes a controlled and transient increase in the permeability of brain capillaries; (iv) the use of molecular Trojan horses, such as peptidomimetic monoclonal antibodies to transport large molecules (e.g. antibodies, recombinant proteins, nonviral gene medicines or RNA interference drugs) across the BBB; and (v) particulate drug carrier systems. Receptor-mediated transport systems exist for certain endogenous peptides, such as insulin and transferrin, enabling these molecules to cross the BBB in vivo.The use of polymers for local drug delivery has greatly expanded the spectrum of drugs available for the treatment of brain diseases, such as malignant tumours and Alzheimer's disease. In addition, various drug delivery systems (e.g. liposomes, microspheres, nanoparticles, nanogels and bionanocapsules) have been used to enhance drug delivery to the brain. Recently, microchips and biodegradable polymers have become important in brain tumour therapy.The intense search for alternative routes of drug delivery (e.g. intranasal drug delivery, convection-enhanced diffusion and intrathecal/intraventricular drug delivery systems) has been driven by the need to overcome the physiological barriers of the brain and to achieve high drug concentrations within the brain. For more than 30 years, considerable efforts have been made to enhance the delivery of therapeutic molecules across the vascular barriers of the CNS. The current challenge is to develop drug delivery strategies that will allow the passage of drug molecules through the BBB in a safe and effective manner.

Radiological findings following postsurgical intratumoral bleomycin injection for cystic craniopharyngioma

OBJECTIVES

The purpose of this study was to compare the radiological findings before and after intratumoral bleomycin injection in patients with cystic craniopharyngioma so as to define the role of adjuvant intracavitary bleomycin chemotherapy for cystic craniopharyngiomas.

PATIENTS AND METHODS

Eleven patients whose craniopharyngioma was confirmed cytologically and/or histologically were retrospectively reviewed. The follow-up duration ranged from 9 to 79 months (mean, 31.6 months). Only the solid portion of the cystic craniopharyngiomas was excised before repeated injections of bleomycin (15-180 mg in total) into the cystic portion through an Ommaya reservoir were given. The patients were evaluated neuroradiologically before and after bleomycin administration.

RESULTS

After the completion of all treatment cycles, the disappearance or shrinkage of the tumor was initially noted in all cases on follow-up CT and/or MR imaging studies. However, tumor recurrence was seen in four cases with a mixed tumor type.

CONCLUSION

Postoperative bleomycin injection in cystic craniopharyngioma does not appear to totally eradicate the tumor and does not stop tumor recurrence unless the cyst is the only portion of the craniopharyngioma that is left. Nevertheless, postoperative bleomycin injection decreases and stabilizes tumor size, and thus may be considered as an option of treatment modalities in patients with predominantly cystic craniopharyngiomas.

Novel advances in drug delivery to brain cancer

The therapy of brain tumors has been limited by a lack of effective methods of drug delivery to the brain. Systemic administration is often associated with toxic side effects and ultimately fails to achieve therapeutic concentrations within a tumor. An attractive strategy that has gained importance in brain tumor therapy has relied on local and controlled delivery of chemotherapeutic agents by biodegradable polymers. This technique allows direct exposure of tumor cells to a therapeutic agent for a prolonged period of time and has been shown to prolong the survival of patients with malignant brain tumors. The use of polymers for local drug delivery greatly expands the spectrum of drugs available for the treatment of malignant brain tumors. This review discusses the rationale for local drug delivery, describes the development of currently available polymer-based therapeutic agents, and highlights examples of promising non-polymer based drug delivery methods for use in the treatment of malignant brain tumors.

Intracavitary therapeutic options in the management of cystic craniopharyngioma

BACKGROUND

Craniopharyngioma remains an entity of controversial management due to its critical anatomical relationships and its well-known recurrence tendency. Total resection, although desirable, is not always accomplished, and it is associated with potentially permanent endocrinological and visual deficits. Consequently, this situation has led to the development of new management strategies seeking lesser morbidity. Because a high percentage of these lesions are cystic, bleomycin and radioactive-emitting sources have been postulated as new therapeutic options with promising results.

DISCUSSION

The information known to date regarding these substances is summarized and we perform a retrospective review of the clinical trials conducted over the past 30 years with special emphasis on outcome, morbidity, and mortality. Two cases from our institution are presented as examples of multimodality management.

CONCLUSION

Overall, these newer options stand out as valid alternatives in the controversial management of these challenging tumors.

Intratumoural bleomycin as a treatment for recurrent cystic craniopharyngioma. Case report and review of the literature

INTRODUCTION

The majority of craniopharyngioma (CF) have a cystic component and only 10% are completely solid. In tumors with a large cystic component, stereotactic drainage or instillation of radioctive and/or chemotherapeutic agents have been used. Only several authors have reported the use of bleomycin for the treatment of cystic CF.

CASE REPORT

The authors present the case of a nineteen years old patient with a recurrent cystic CF who was treated with intratumoral injections of bleomycin. The patient had been operated on three times before because of regrowth of the tumor. This last time he had a severe disturbance of his visual acuity and a huge regrowth of the cystic CF. An intracystic catheter stereotactically placed was connected to an Ommaya reservoir and, after assuring the impermeability of the cyst, bleomycin was administered through the reservoir up to a total dose of 45mg distributed in six doses. No complications were detected during and after the procedure. A MR performed 4 months after treatment showed a clear reduction in the size of the cyst but 10 months later a new regrowth of the cyst was detected by MR with no new signs or symptoms. A total dose of 30 mg divided in six doses was administered. No complications occurred. The MR 18 months after the first treatment showed the reduction in size of the tumor. The ophtalmological study showed almost normal visual acuity in both eyes.

DISCUSSION

Although there is not an stablished protocol for the indication and the form of application of intracystic bleomycin, results with this treatment for cystic CF seem good in the literature. However, the risk of local complications after the administration of intratumoural bleomycin in these patients is around 10%, and some fatal toxic reactions have been recently reported.

CONCLUSION

Intracystic administration of bleomycin is a valid option as adjuvant therapy for CF in patients with recurrences that are not surgical candidates because of the high risk of complications. The role of bleomycin as a primary treatment for CF and treatment protocols remain to be stablished with additional studies.

A phase I trial of continuously infused intratumoral bleomycin for the treatment of recurrent glioblastoma multiforme

Intratumoral (IT) chemotherapy has theoretical advantages in the treatment of brain tumors. The blood-brain barrier is not a factor in drug delivery, and large concentrations of drug can be instilled in the tumor with little systemic toxicity. Bleomycin has activity against gliomas and is a cell cycle selective agent whose efficacy should be enhanced by continuous infusion. We performed a phase I trial to test the feasibility of IT chemotherapy using a refillable, sustained release device, and to determine the maximum tolerable dose of IT bleomycin. The study was an open-ended dose escalation study. A modified Ommaya reservoir (containing a semipermeable membrane) was implanted with the delivery tube in the center of the tumor. Groups of three patients with recurrent glioblastoma multiforme were entered at progressively higher dose levels of bleomycin. The study closed when all patients at a given starting dose level developed toxicity. Nine patients received doses ranging from 5 to 34 U/wk; the median total cumulative dose was 195 U. No dose limiting systemic toxicity was detected. Neurologic toxicity occurred only at doses above 16 U/wk. We conclude that continuously infused IT bleomycin is well tolerated; the MTD (and recommended dose for a phase II efficacy trial) of IT bleomycin is 16 U/wk.

Intratumoral doxorubicin in patients with malignant brain gliomas

The objective of the study was to evaluate the safety and therapeutic efficacy of intralesional administration of doxorubicin in brain gliomas. Ten patients with recurrent grade III or IV glioma were enrolled in the study, after the second operation. All patients had not responded to radiation therapy. Chemotherapy was administered directly in the tumor through an Ommaya pump placed in the site of disease at the time of craniotomy. Doxorubicin 0.5 mg was administered in the Ommaya reservoir every 24 hours on days 1 to 10. Patients were evaluated at 6- to 8-week intervals until tumor progression and death. All patients were evaluated for response. Six of 10 patients had clinical improvement lasting from 12 to 73 weeks. Objective radiologic response was observed in 5 of 10 (50%) patients. One patient achieved complete response with time to disease progression of 119 weeks, and 4 patients had a partial response (duration 14-39 weeks) with 25% or more reduction of tumor volume on computed tomography scan compared with pretreatment measurements. Time to disease progression in patients who responded after the intratumoral chemotherapy was 39.83 +/- 40.5 weeks. One additional patient had stable disease for a duration of 12 weeks. The median survival of the patients with response was 55.17 +/- 54.22 weeks (range: 21-164 weeks), whereas survival of those who did not respond was 17.0 +/- 12.36 weeks (range: 8-35) (Mann Whitney U test: z = -2.13, p = 0.033). The median survival of all 10 patients was 39.9 +/- 45.52 weeks (range: 8-73 weeks). Bifrontal headache was reported in 4 of 10 patients immediately after the administration of doxorubicin. There were no other clinically significant adverse reactions either in the brain or systematically. Intralesional administration of doxorubicin appears to be a safe and effective treatment and should be further explored in the management of brain gliomas resistant to conventional forms of treatment.

Interstitial chemotherapy plus systemic chemotherapy for glioblastoma patients: improved survival in sequential studies

We investigated the efficacy of 3 different systemic chemotherapy regimes in 122 patients with histologically confirmed glioblastoma, KPS > 60, age < 65. Locoregional chemotherapy was delivered to 22 patients from all three systemic chemotherapy groups. Chemotherapy was given before and during radiotherapy, which was the same for all patients consisting of unconventional fractionation with a break between courses. Survival (Kaplan-Meier) was significantly longer in the subgroup receiving cisplatinum plus BCNU compared to those receiving cisplatinum plus etoposide or carboplatinum plus BCNU with median survival time 21.5 months, 15 months and 15 months respectively (log rank test p = 0.01). Survival was also significantly longer in patients who received locoregional therapy compared to those who received only systemic chemotherapy (21 vs 15 months, p = 0.01). Univariate analysis showed that age, postoperative Karnofsky status and extent of resection were not predictive of survival in the series, although there were trends to better outcome in younger patients and those undergoing total/subtotal resection. Age, systemic chemotherapy type and interstitial treatment were included in a multivariate analysis, and both locoregional treatment and chemotherapy with cisplatinum plus BCNU were significantly predictive of survival [P = 0.01]. These encouraging preliminary results suggest that further trials with locoregional and systemic therapy prior to radiotherapy are worth pursuing.

Interstitial chemotherapy with mitoxantrone in recurrent malignant glioma: preliminary data

We undertook a phase I-II trail of loco-regional mitoxantrone in 12 patients affected by malignant gliomas. Mitoxantrone was delivered at tumor recurrence by Ommaya reservoir, with 2 cycles and a 1 month interval between each cycle, in conjunction with systemic chemotherapy (8 pts) or not (4 pts). Treatment tolerability was good, and 9 of the patients showed either response or stable disease at the end of the treatment schedule. Regardless of associated chemotherapy, time to further tumor progression was at 6 months. A combination of early systemic and loco-regional chemotherapy with surgery and radiotherapy seems worth while pursuing in the therapeutic approach to malignant gliomas.

Implantable pumps for drug delivery to the brain

This article reviews the role of implantable pumps in the treatment of CNS tumors. Systemic administration of chemotherapeutic agents has been associated with various problems, including adverse systemic effects and decreased concentration of the drug at the target site. Continuous infusion of chemotherapeutic agents with implantable pumps have been used in an attempt to overcome these problems. Various different chemotherapeutic agents have been used for this purpose, and catheters have been placed in the intraspinal, intraventricular and intratumoral locations.

Convection-enhanced delivery of macromolecules in the brain

For many compounds (neurotrophic factors, antibodies, growth factors, genetic vectors, enzymes) slow diffusion in the brain severely limits drug distribution and effect after direct drug administration into brain parenchyma. We investigated convection as a means to enhance the distribution of the large and small molecules 111In-labeled transferrin (111In-Tf; M(r), 80,000) and [14C]sucrose (M(r), 359) over centimeter distances by maintaining a pressure gradient during interstitial infusion into white matter to generate bulk flow through the brain interstitium. The volume of distribution (Vd) containing > or = 1% concentration of infusion solution increased linearly with the infusion volume (Vi) for 111In-Tf(Vd/Vi, 6:1) and [14C]sucrose (Vd/Vi, 13:1). Twenty-four hours after infusion, the distribution of 111In-Tf was increased and more homogeneous, and penetration into gray matter had occurred. By using convection to supplement simple diffusion, enhanced distribution of large and small molecules can be obtained in the brain while achieving drug concentrations orders of magnitude greater than systemic levels.

Efficacy of direct intratumoral therapy with targeted protein toxins for solid human gliomas in nude mice

Targeted protein toxins are a new class of reagents with the potential for great tumor selectivity and cytotoxic potency. Two such compounds were studied: 1) Tf-CRM107, a conjugate of human transferrin (Tf) and diphtheria toxin with a point mutation (CRM107); and 2) 454A12-rRA, a conjugate of a monoclonal antibody (454A12) to the human Tf receptor and recombinant ricin A chain (rRA). Both compounds are potent and specific in killing human glioblastoma cell lines in vitro. The authors investigated the activity of these reagents administered intratumorally against solid U251 MG human gliomas in vivo. Nude mice with established U251 MG flank tumors (0.5 to 1.0 cm in diameter) were randomly assigned to be treated with 100-microliters intratumoral injections of Tf-CRM107 (10 micrograms) or 454A12-rRA (10 micrograms), equimolar doses of CRM107 (4.3 micrograms), 454A12 antibody (7.5 micrograms), or rRA (1.5 micrograms), or phosphate-buffered saline (PBS) every 2 days for a total of four doses. Tumor volume and animal weight were assessed by a blinded observer before each treatment and biweekly for 30 days after initiating therapy. With Tf-CRM107 administration, tumor regression of greater than 95% occurred by Day 14 (p < 0.01) and tumors did not recur by Day 30. Treatment with 454A12-rRA caused a 30% decrease in tumor volume by Day 14 (p < 0.01). Treatment with equimolar doses of the unconjugated targeted protein toxin components CRM107, 454A12, or rRA caused significant U251 MG tumor growth inhibition, but the effects were less potent than the antitumor effects of the conjugates. This study also characterized the dose-response effect of Tf-CRM107 on tumor growth and tumor weight on Day 30. Nude mice with established U251 MG flank tumors (0.5 to 1.0 cm in diameter) were treated with 100-microliters intratumoral injections of 10, 1.0, or 0.1 microgram of Tf-CRM107 or PBS every 2 days for a total of four doses. All three doses of Tf-CRM107 significantly inhibited tumor growth by Day 14 (p < 0.01) and at Day 30 (p < 0.05), with a significant dose-response relationship. This study demonstrated in vivo efficacy of the targeted toxins Tf-CRM107 and 454A12-rRA against a human glioma. With intratumoral administration, the effect of Tf-CRM107 was tumor-specific and in some animals curative. Regional therapy with these potent tumor-specific agents using direct intratumoral infusion should limit systemic toxicity and may be efficacious against brain tumors.

The 9L rat brain tumor model for pre-clinical investigation of radiation-chemotherapy interactions

The rat 9L gliosarcoma brain tumor model has been used for more than thirty years to investigate a variety of potential therapeutic agents, combinations, schedules, and approaches that might be applicable to the management of high-grade malignant brain tumors in man. When tumor cells are implanted intracerebrally, a solid tumor grows until its mass results in the death of the animal, typically between 20 and 30 days postinoculation. Radiation therapy (either single or fractionated doses) is effective at prolonging survival in a dose-dependent manner. Numerous cancer chemotherapeutic agents, by a variety of doses, schedules, and routes of delivery, have demonstrated therapeutic efficacy in the 9L model. The combination of radiation and agents such as AZQ, BCNU, bleomycin, and cis-platinum has resulted in prolongation of survival that is significantly better than either agent used alone, without exceeding the tolerance of critical normal tissues. These pre-clinical data suggest that combining standard fractionated radiation therapy with appropriate concomitant cytotoxic chemotherapeutic agents might benefit patients with high-grade brain tumors.

Combination of aziridinylbenzoquinone and cis-platinum with radiation therapy in the 9L rat brain tumor model

PURPOSE

We evaluated the potentiating effects of aziridinylbenzoquinone (AZQ) and cis-platinum on the prolongation of survival by radiation therapy in a rat brain tumor model.

METHODS AND MATERIALS

On day 10 following intracranial inoculation of the 9L gliosarcoma, Fischer 344 rats were treated with radiation therapy (Cesium-137 source irradiator) and/or chemotherapy delivered either systemically (intraperitoneal or intravenous), or intracranially directly into the tumor in a volume of 5 microliters. Increased life spans were calculated relative to the median survival time for the control (ILS-C) or to the median survival time for radiation therapy only (ILS-RT) group.

RESULTS

Median survival time for untreated rats was 22 +/- 3 days for seven experiments. Radiation therapy (16 Gy) produced a significant (p < 0.002) improvement in survival, with an average ILS-C of 75 +/- 19%. Systemic AZQ (1 or 5 intravenous injections of 0.5 mg/kg) produced ILS's of 0 and 23%, the latter being significant (p = 0.002). When added to radiation therapy, there were further improvements (ILS-RT's of 47 and 72%), but these were not significant. Intratumor AZQ (40 or 50 micrograms intracranially) produced significant ILS-C's of 30 and 33% (p = 0.01 and 0.0002, respectively). Added to radiation therapy, intracranial AZQ produced improvements (ILS-RT's of 5 and 102%), with only the latter being significantly improved (p = 0.009). Cis-platinum (3 micrograms intracranially) produced ILS-C's of 13 and 6%, neither significantly different from controls. Added to radiation therapy, cisplatinum caused improvements (ILS-RT's of 18 and 64%), with only the latter significant (p = 0.049).

CONCLUSION

These results demonstrate that AZQ delivered systemically, and AZQ and cis-platinum delivered intracranially, can produce statistically significant improvements in the survival of rats burdened with the 9L brain tumor. The agents delivered intracranially significantly potentiated the prolongation of survival obtained by radiation therapy. This preclinical evidence suggests that combining radiation therapy with these cytotoxic chemotherapeutic agents may benefit patients with high-grade malignant brain tumors.

Interstitial chemotherapy for brain tumors: review

An extensive effort to search for curative chemotherapeutic approaches has found no 'breakthrough' in management of patients with malignant brain tumors. Despite the trials with new agents or protocols of multiple agents, systemic chemotherapy has failed to provide reliable clinical response. Interstitial chemotherapy has been practiced for malignant brain tumors with administering chemotherapeutic compounds directly into the tumor which provide increased and prolonged drug concentration in the tumor, reduction of systemic toxicity and bypassing the blood-brain barrier. These theoretical advantages encourage further pursuing interstitial chemotherapy for patients with malignant brain tumors who would otherwise be always fatal. In this review, the literature has been reviewed to identify methods, toxicity, and efficacy of interstitial chemotherapy. Clinical and experimental data indicate limited toxicity and promising efficacy. Various methods to administer the agents were utilized; intraoperative topical application, local injections through catheters or implantable controlled drug delivery system. Selection of ideal chemotherapeutic agents and development of drug delivery system need further investigations.

Combination of radiation therapy and intracranial bleomycin in the 9L rat brain tumor model

The rat 9L brain tumor model was used to investigate the therapeutic potential of a combined modality approach using intracranial Bleomycin and radiation therapy. Bolus Bleomycin was delivered intracranially into the tumor volume via cannula guides; for continuous infusions, osmotic mini-pumps were implanted subcutaneously between the scapulae with flexible tubing to deliver the drug directly into the tumor and brain. Two to six bolus injections of Bleomycin (1 unit/kg each) over 5-11 days produced modest (usually statistically significant, p less than 0.05) increases in the median survival time compared to controls. Continuous infusion of Bleomycin by osmotic pump (10 units/kg over 7 days or 15 units/kg over 14 days) was also effective at significantly increasing median survival times compared to that of controls. Radiation therapy schedules of 10 daily fractions in 12 days (2 weeks) or 10 twice-daily fractions in 5 days produced dose-dependent increases in median survival time. Multiple bolus injections of Bleomycin when combined with fractionated radiation therapy significantly increased the median survival time due to fractionated radiation therapy alone for low doses (40 or 50 Gy). However, at higher radiation doses, the addition of Bleomycin either had no effect on median survival time or actually shortened it. Continuous infusion of Bleomycin by osmotic pump was effective when added to low dose radiation therapy in several experiments, twice for a total radiation dose of 50 Gy and once for radiation therapy of 60 Gy. However, it was also observed (once for 60 Gy and twice for 70 Gy) that the addition of continuous infusion Bleomycin either had no effect or served to decrease the improvement of median survival time obtained by radiation therapy alone. Thus, we conclude that increases in normal tissue toxicity can prevent full attainment of improved therapeutic advantage from the addition of Bleomycin to fractionated radiation therapy in the rat 9L model. These results should be considered when attempts are made to combine radiation therapy and intracranial Bleomycin for the treatment of patients with primary malignant brain tumors.

Novel CNS-directed drug delivery systems in Alzheimer's disease and other neurological disorders

Increasing knowledge of the neurochemical aspects of central nervous system function raises the possibility of treating Alzheimer's disease (AD) and other neurological diseases by the appropriate manipulation of neurotransmitters, neuromodulators, neurohormones or neurotrophic factors. Clinical application of this knowledge may, however, be inhibited by long standing problems with drug delivery to the central nervous system (CNS). Novel, CNS-directed, drug delivery systems might be used to overcome many of these problems. The problems encountered in drug delivery to the brain, present experience with the clinical use of some novel drug delivery systems and the advantages and disadvantages of these systems will be discussed.

The role of chemotherapy in the treatment of gliomas in adults

Glioblastomas and previously irradiated recurrent gliomas remain incurable. Chemotherapy is able to palliate patients by shrinking tumors, thereby improving neurological status and quality of life. Chemotherapy may also be capable of prolonging survival in some instances. The effectiveness of chemotherapy against gliomas is comparable to the efficacy of chemotherapy against many other solid tumors. When given in an adjuvant setting along with radiation postoperatively, studies suggest that the nitrosoureas, dibromodulcitol, dianhydrogalactitol, procarbazine, teniposide, dacarbazine, and cisplatin may possibly be useful, although results for many of these drugs are inconclusive. Some chemotherapy combinations also appear to be useful in an adjuvant setting, particularly BCNU plus ifosfamide, BCNU plus cisplatin, CCNU plus dibromodulcitol, and CCNU plus lonidamine. However, there is not yet conclusive evidence that combination chemotherapy is superior to single agent adjuvant chemotherapy in the treatment of gliomas. While the use of chemotherapy prior to postoperative cranial radiation is worthy of further study, it has not to date proven to be more effective than chemotherapy combined with radiation. In patients whose tumors have recurred following radiation, palliation may be achieved with the nitrosoureas, procarbazine, teniposide, and diaziquone. Cisplatin, high dose methotrexate, the interferons, and a variety of other medications also may be of use. As in the case of adjuvant chemotherapy, chemotherapy combinations for recurrent tumor have not been conclusively demonstrated to be superior to single agent treatment, although some CCNU-based combinations are of interest. Many different chemotherapy drugs have been administered by intracarotid infusion. There is a moderately high risk of serious local retinal and neurological toxicity using this approach, and efficacy has not been proven to be improved by this approach. However, further studies of intraarterial administration of chemotherapy are warranted in light of theoretical considerations, pharmacological observations of enhanced local drug concentrations, and the observation that patients who have failed the same drugs intravenously may respond when lower doses of the drug are administered intraarterially. In addition, some patients have had tumor shrinkage in the area infused while tumor has grown in other areas. Thus, while intracarotid chemotherapy must be regarded as still investigational and potentially quite toxic, further studies are indicated. High dose chemotherapy has been administered in combination with autologous bone marrow rescue. High response rates and prolonged survival durations have been reported in some instances, justifying further study despite substantial toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)

Intraperitoneal bleomycin for ventriculoperitoneal spread of a hypothalamic astrocytoma

A pediatric patient is presented in whom malignant ascites developed after ventriculoperitoneal shunt placement for a suprasellar astrocytoma. Paracentesis followed by intraperitoneal bleomycin resulted in decreased fluid re-accumulation with minimal side effects. A review of the literature shows that intracavitary chemotherapy, including bleomycin, can result in safe, effective relief of malignant effusion associated with adult tumors. We have demonstrated that such treatment is also applicable to the pediatric population. In this case, the effectiveness of intracavitary bleomycin may be related to its direct action against brain glioma cells. The need for effective treatment of malignant effusions in pediatric patients is growing because of their increased survival time with tumor. We propose that intracavitary bleomycin may provide relief from this potential complication of childhood solid tumors.