Multiple Courses Of Treatment Research Articles

Intermittent short courses of cyclosporine microemulsion for the long-term management of psoriasis: A 2-year cohort study

Background: Cyclosporine is effective in psoriasis, but long-term continuous therapy may be limited by renal impairment and hypertension. Intermittent short courses of treatment should minimize side effects and improve the risk-benefit ratio. Objective: Our purpose was to assess the long-term efficacy and safety of intermittent short courses of the microemulsion formulation of cyclosporine (Neoral) in the management of chronic plaque psoriasis unresponsive to topical therapies. Methods: In a multicenter open cohort study, 76 subjects were treated intermittently over a 2-year period. Patients with chronic plaque psoriasis were treated with cyclosporine until clearance of psoriasis or for a maximum of 12 weeks. Patients were then randomized into two groups. Group A stopped cyclosporine abruptly, whereas group B had the dose reduced by 1 mg/kg per day each week until cessation, which was within 4 weeks. On relapsing, patients received further courses of cyclosporine. Intermittent treatment was continued in this way for 42 years. Results: There was no statistically significant difference in the percentage of time in remission during the 2-year period between patients randomized to stop cyclosporine abruptly (56.2%) and patients randomized to taper cyclosporine within 4 weeks (61.8%). The mean percentage of time that patients received treatment during the study was 40.5% for randomization group A, 46.2% for randomization group B, and 42.8% overall. The median time to relapse was 115.5 days after the first treatment course but became progressively shorter after multiple treatment courses. Mean blood pressure and serum creatinine levels did not show any clinically significant changes over time. Conclusions: This study indicates that intermittent short courses of cyclosporine are effective in patients with moderate to severe psoriasis for up to 2 years while improving the safety profile relative to continuous cyclosporine monotherapy.

Kawasaki Disease.

Kawasaki disease is an acute vasculitis of unknown cause that occurs predominantly in infants and young children and produces coronary artery aneurysms in approximately 15% to 25% of those affected. In the United States, Kawasaki disease is more commonly the cause of noncongenital heart disease in children than is acute rheumatic fever. Therapy for Kawasaki disease in the acute phase is aimed at reducing inflammation of the coronary artery wall and preventing coronary thrombosis; treatment with high-dose intravenous gamma globulin and aspirin has become the standard of care and reduces the risk of development of coronary artery aneurysms by three- to fivefold. Even when treated with high-dose intravenous immune globulin G (IVIG) regimens within the first 10 days of illness, however, approximately 5% of children with Kawasaki disease develop at least transient coronary artery dilation, and 1% develop giant aneurysms. For those with persistent or recrudescent fever despite initial IVIG infusion, multiple courses of gamma globulin and treatment with cortico- steroids may be indicated. Early experience suggests that therapies aimed at reducing the amount of tumor necrosis factor alpha have a role. For those who develop coronary artery aneurysms, chronic antithrombotic regimens are instituted. When aneurysms are small or moderate in size, aspirin alone may be sufficient, but for patients with giant aneurysms, most experts choose to treat Kawasaki disease with aspirin plus warfarin. Acute coronary thromboses are treated with platelet IIb/IIIa antagonists and thrombolytic therapy. For children with coronary artery stenoses and consequent ischemic heart disease, the therapeutic armamentarium is similar to that used in adults with atherosclerotic coronary artery disease and includes coronary artery bypass grafting and transcatheter interventions.

Evaluating multiple treatment courses in clinical trials

Evaluating multiple treatment courses in clinical trials

Evaluating multiple treatment courses in clinical trials

In oncology, a patient's treatment often involves multiple courses of chemotherapy. The most common medical practice in choosing treatments for successive courses is to repeat a treatment that is successful in a given course and otherwise switch to a different treatment. Patient outcome thus consists of a sequence of dependent response variables and corresponding treatments. Despite the widespread use of such adaptive 'play-the-winner-and-drop-the-loser' algorithms in medical settings involving multiple treatment courses, most statistical methods for treatment evaluation characterize early patient outcome as a single response to a single treatment, resulting in a substantial loss of information. In this paper, we provide a statistical framework for multi-course clinical trials involving some variant of the play-the-winner-and-drop-the-loser strategy. The aim is to design and conduct the trial to more closely reflect actual clinical practice, and thus increase the amount of information per patient. The proposed design is similar to a multi-stage cross-over trial, with the essential difference that here all treatments after the first course are assigned adaptively. We illustrate the method by application to a randomized phase II trial for androgen independent prostate cancer. We consider the goals of selecting one best treatment, or selecting a best ordered pair of treatments with the second given if the first fails to achieve a patient success. A simulation study is reported, and extensions to trials involving toxicity or regimen-related death are discussed.

Multiple courses of antenatal glucocorticoid treatment and fetal outcome.

Thanks to the US National Institutes of Health Consensus Conference, the odds of antenatal use of glucocorticoids for preventing severe neonatal complications of premature delivery have significantly increased these last years. The belief that neonatal benefits last up to 7 days after the first course and administration of further courses is safe has led many obstetricians to prescribe multiple antenatal glucocorticoid courses. Whether multiple courses offer an advantage over a single course has not been demonstrated. In contrast, there are accumulating evidence suggesting that this practice may have short and long-term side effects. The potential benefits and side effects of multiple antenatal courses of glucocorticoids, extrapolated from experimental data and observational studies, are detailed in this review. Until the results of ongoing randomized trials with long term follow-up are available, the practice of giving multiple courses of glucocorticoids to women should be considered with the greatest caution.

Diagnosis of Penicillin, Amoxicillin, and Cephalosporin Allergy:Reliability of Examination Assessed by Skin Testing and Oral Challenge

Pichichero ME, Pichichero DMJ Pediatr.1321998137143The major aims were to 1) assess the reliability of pediatrician-diagnosed allergic reactions to commonly used β-lactam antibiotics based on the examination at the time of reaction followed by elective skin testing and oral challenge, and 2) monitor prospectively the predictive value of negative skin testing for subsequent reactions to antibiotics administered.Children and adolescents (n = 247) experiencing an adverse reaction to penicillin, amoxicillin, and/or an oral cephalosporin sufficient to lead to the recommendation to avoid further use of the drug.Skin testing with penicillin G, commercial benzylpenicilloyl phosphate (Pre-pen), penicillin minor determinant mixture (MDM), ampicillin, cefazolin, cefuroxime, and/or ceftriaxone was performed according to the suspected cause of the reaction. This was followed by an oral challenge, repeat testing, and prospective follow-up if no reactions were observed.Overall, 84 (34%) of 247 patients had an immunoglobulin E (IgE)-type reaction on skin testing or oral challenge. Twenty-seven (32%) of 85 suspected penicillin reactions, 53 (34%) of 156 suspected amoxicillin reactions, and 13 (50%) of 26 suspected cephalosporin reactions were felt to be IgE-mediated. Positive skin tests were observed in 20 patients with non-IgE-type adverse reactions, including 15 patients with only a pruritic polymorphous rash. No reactions to oral challenge were severe after negative skin testing. One hundred sixty-three patients received multiple treatment courses with β-lactam antibiotics after a negative skin test and oral challenge and 3 (1.8%) had adverse IgE-type reactions, all of which were mild.Physician-diagnosed allergic reactions to β-lactam antibiotics based on the examination at the time of the reaction is more accurate than patient history alone, but still overestimates the rate of true allergy in 66% of patients. Elective penicillin, amoxicillin, and cephalosporin skin testing and oral challenge protocols are necessary to identify patients at risk.How often (ie, monthly, weekly, or even daily) do you encounter a patient with a history of a β-lactam allergy? In our current era of emerging antibiotic resistance, this clinical issue has reached an even greater degree of importance. This article addressing the diagnosis of β-lactam allergy should strike a cord with both pediatricians and allergy/immunology specialists. There are several useful “take home” messages. First, examination of the patient at the time of the adverse antibiotic reaction accurately diagnosed an IgE-mediated reaction only 30% of the time. Second, young and middle-aged adults (ages 20–49) seemed to have the greatest risk of acute allergic reactions to antibiotics. Third, this investigation confirms the safety of testing for penicillin allergy with penicillin G, Pre-pen, and MDM, as well as with cephalosporin skin testing reagents. Fourth, after negative skin testing, use of an oral challenge is the safest method of confirming the negative result. Fifth, while a potential for increased hypersensitivity to first-generation cephalosporins exists in those patients who have histories of penicillin, second- and third-generation cephalosporins have a lower incidence of allergic reactions. Finally, patients observed during subsequent, multiple treatment courses with β-lactams after negative testing and oral challenge rarely had mild IgE-mediated reactions.

Diagnosis of penicillin, amoxicillin, and cephalosporin allergy: Reliability of examination assessed by skin testing and oral challenge

The specificity of pediatrician-diagnosed allergy reactions to penicillin, amoxicillin, and oral cephalosporins, which was based on contemporaneous examination of the patient, was evaluated by an elective skin testing program. Children and adolescents ( n = 247) experiencing an adverse reaction to penicillin, amoxicillin, and/or an oral cephalosporin sufficient to lead to the recommendation to avoid further use were enrolled. Skin testing with penicillin G, commercial benzylpenicilloyl phosphate, penicillin minor determinate mixture, ampicillin, cefazolin, cefuroxime, and ceftriaxone was performed according to the suspected drug allergy followed by an oral challenge, repeat testing, and prospective follow-up if no reactions were observed. Overall, 84 (34.0%) of 247 patients had an IgE-type reaction on skin testing or oral challenge. Twenty-seven (32%) of 85 suspected penicillin reactions, 53 (34%) of 156 suspected amoxicillin reactions, and 13 (50%) of 26 suspected cephalosporin reactions were shown to be IgE mediated. Positive skin tests were observed in 20 patients with non-IgE-type clinical adverse reactions, including 15 patients with only a pruritic polymorphous rash. No reactions to oral challenge were severe after negative skin testing. One hundred sixty-three patients received multiple treatment courses with beta-lactam antibiotics after a negative skin testing procedure and three (1.8%) had adverse IgE reactions, all of which were mild. Physician-diagnosed allergic reactions to beta-lactam antibiotics based on patient examination at the time of the reaction is more accurate than patient history alone but still overestimates the rate of possible true allergy in 66% of patients. Elective penicillin, amoxicillin, and cephalosporin skin testing and oral challenge protocols are necessary to identify patients not at risk. (J Pediatr 1998;132:137-43)

GYNECOLOGY AND FAMILY PLANNING CARE FOR THE WOMAN INFECTED WITH HIV

This article reviews the interactions between HIV infection and a variety of gynecologic conditions, including lower genital tract neoplasia, pelvic inflammatory disease, menstrual disorders, sexually transmitted diseases, and vaginitis. Important considerations in choosing a family planning method for women infected with HIV-infected women will respond to standard therapy, but require multiple courses of treatment or use of innovative treatment methods. All HIV-infected women deserve careful evaluation for and treatment of gynecologic diseases.

Variations in fluconazole susceptibility and DNA subtyping of multiple Candida albicans colonies from patients with AIDS and oral candidiasis suffering one or more episodes of infection.

Five Candida albicans colonies from each infection in AIDS patients receiving fluconazole therapy for oropharyngeal candidiasis over a 2-year period were evaluated by antifungal susceptibility testing and DNA subtyping, and the results were correlated with clinical response to determine the occurrence of clinically significant selection of more-resistant C. albicans over multiple infections. A total of 534 C. albicans isolates were obtained from 38 patients who exhibited 84 episodes of infection. Antifungal susceptibility testing revealed that the MICs for 93% of the isolates were < or = 8.0 microg/ml and the MICs for 7% of the isolates were > or = 64 microg/ml. DNA subtyping revealed 70 different subtypes, with 78% of patients with one infection exhibiting one DNA subtype and 80% of patients with more than one infection exhibiting multiple DNA subtypes. Also, patients who had multiple infections had lower CD4 counts than those with single infections. Differences between the single-infection group and the multiple-infection group regarding the number of DNA subtypes and CD4 counts were both statistically significant. Of the 74 evaluable infections all were successfully treated with regular-dose (100-mg/day) fluconazole, except for three patients who ultimately responded to higher-dose fluconazole. Only one patient may have shown clinically significant selection of a more-resistant C. albicans strain over multiple courses of treatment. Interestingly, MICs reached only 8.0 microg/ml, even though doses of 400 mg of fluconazole were necessary for clinical cure.

A single centre experience with allogeneic stem cell transplantation for severe aplastic anaemia in childhood.

Severe aplastic anaemia (SAA) is a rare disorder which has a fatal course when allogeneic stem cell transplantation (SCT) or an immunosuppressive regimen is not applied. Stem cell replacement is the only curative approach for these patients but it is limited by the availability of a compatible donor. Between 1982 and 1993, 18 children (15 boys, 3 girls) with SAA and HLA identical, MLC negative donors underwent SCT in our institution. SAA was preceded by viral infection in 8 patients (3x hepatitis, 1x measles, 1x herpes simplex infection and 3x viral upper respiratory tract infections). It was drug-associated in one and idiopathic in the 9 others. The median age at diagnosis was 9.7 years (range, 2 months to 16 years). Pretreatments included corticosteroids in 11/18 patients, androgens in 4 patients in addition, two had received cyclosporin A (CSA). One patient progressing from Diamond- Blackfan anaemia to SAA had multiple immunosuppressive treatment courses over 7 years before his grand-uncle was identified as donor while 4 patients had no treatment prior to SCT. Early SCT (within 90 days after diagnosis) was performed in 9/18 patients and the median interval between diagnosis and SCT was 2.6 months (range, 0.5 to 7 years). The stem cell source was the bone marrow (BM) of a syngeneic twin in 2 patients, the BM (13 patients) or the cord blood (1 patient) of a sibling whilst it was BM from a HLA-phenotypical family donor (1 father, 1 grand-uncle) in two patients. Cyclophosphamide 50 mg/kg on 4 consecutive days was given as preparative regimen to 16 patients but not to the two syngeneic twins. Rejection prophylaxis included total lymphoid irradiation in 5/16 patients while in the other 11 patients donor buffy coat cells were given on days +1 to +4. The syngeneic twins had no need for either approach. Patients received a median number of 3.7 x 10(8)/kg nucleated cells (range, 2.6 to 6.7). Prophylaxis of graft versus host disease (GVHD) was carried out with MTX alone (n = 12), with CSA alone (n = 2) or with both (n = 4). All patients received standard supportive care. The overall survival is 89% at the median observation time of 100 months. The median time to reach 500 granulocytes was 24 days (range, 15 to 40). Median time to become transfusion independent after BMT was 30 days for platelets (range, 2 to 111) and was 28 days for packed red blood cells (range, 6 to 128). Acute GVHD was observed in 10/18 patients and involved only skin in 6 patients, skin and liver or gut in two patients and all 3 organs in another two patients. Seven of 10 patients had grade 1 to 2 a GVHD toxicity, whereas 3 patients experienced grade 3 to 4 acute GVHD. Chronic GVHD developed in 5 patients. Acute transplant related mortality was 5.5%. Cause of death was persisting non engraftment till day +180 after 2 transplant procedures in a boy with previous platelet transfusions from his mother. Late mortality occurred in 2 patients: one chronic GVHD associated haemorrhage 20 months after SCT and one chronic GVHD associated septicaemia 10 years after SCT. Although this report reflects patients data accumulated over 15 years, results compare favourably with more recent survival data. Acute and late transplant related toxicity was low in patients undergoing early transplantation with adequate prior supportive care. This data confirms that SCT still should be the first treatment choice if an HLA identical sibling is available.

Correlation of seroreactivity with response to antibiotics in pediatric Lyme borreliosis.

Response to treatment with antibiotics was compared with serologic reactivity and clinical symptoms in a pediatric population with presumptive diagnoses of Lyme borreliosis. The population analyzed for this study consisted of a subset of a larger Lyme clinic population being monitored as part of a prospective study on pediatric Lyme borreliosis. All patients resided in an area in which Ixodes scapularis and Borrelia burgdorferi are considered endemic. Serum from patients was tested by enzyme-linked immunosorbent assay and Western blotting. Response to antibiotics was evaluated by members of a pediatric Lyme clinic. Results showed that positive serologic test results correlate with a favorable response to antibiotics, as does the presence of erythema migrans (EM), regardless of serologic status. Seronegative patients without EM had chronic fatigue and arthralgia and/or myalgia as primary symptoms and did not respond to antibiotics, even when multiple courses of treatment were given. These results indicate that serologic tests designed to have high specificity can reliably rule out Lyme borreliosis in patients with chronic symptoms, thus preventing unnecessary treatment with antibiotics.

A three-nucleotide deletion in the UL97 open reading frame is responsible for the ganciclovir resistance of a human cytomegalovirus clinical isolate.

Multiple human cytomegalovirus (HCMV) strains frequently coexist in patients with AIDS, and chronic ganciclovir treatment may favor the emergence of ganciclovir-resistant viral mutants. We report the molecular and biochemical characterization of a HCMV ganciclovir-resistant strain (VR3480) previously recovered from a patient with AIDS who was undergoing multiple courses of ganciclovir treatment (G. Gerna, F. Baldanti, M. Zavattoni, A. Sarasini, E. Percivalle, and M. G. Revello, Antiviral Res. 19:333-345, 1992). Ganciclovir resistance of strain VR3480 was related to impaired ability to monophosphorylate the drug, as indicated by the finding that ganciclovir phosphorylation values for VR3480 were 30% of those shown by the HCMV reference strain AD169 in an in vitro activity assay. Sequencing of the UL97 gene of VR3480, which encodes the viral kinase responsible for ganciclovir phosphorylation, showed an in-frame deletion of three nucleotides resulting in the loss of a leucine at position 595 in the polypeptide. Mutant VR3480 UL97 DNA was able to transfer resistance to the AD169 strain in marker rescue experiments. Analysis of virus isolates and blood polymorphonuclear leukocyte samples spanning the 2-year follow-up period of the patient showed that ganciclovir-resistant strain VR3480 arose ex novo during prolonged antiviral treatment and accounted for the majority of virus load circulating in blood during the period of clinical resistance to ganciclovir treatment.

Intermittent G-CSF to maintain dose intensity of chemotherapy for Hodgkin's disease.

As the ability to deliver full dose chemotherapy on time in Hodgkin's disease has been reported to be an important determinant of response,1 our department has adopted a policy of using G-CSF in patients receiving adriamycin, bleomycin, vinblastine and dacarbazine (ABYD) in whom neutropenia would otherwise necessitate dose reduction or delay. This is based on reports that G-CISF following myelosuppressive chemotherapy reduces the period of neutropenia, resulting in less fever2 and the ability to deliver multiple courses of full-dose treatment without delay.3 In these reports, G-CSF was administered daily, but whether this represents the optimal schedule for this purpose has yet to be established.

Radiotherapy in the management of epidemic Kaposi's sarcoma

Purpose : This study is presented to help define the role of radiotherapy in the management of epidemic Kaposi's sarcoma. Methods and Materials : Between June 1986 and June 1993, we treated 453 patients who had acquired immunodeficiency syndrome related Kaposi's sarcoma. Two hundred fifty-two patients (55.6%) had received previous treatment for their Kaposi's sarcoma: 228 (55.3%) with interferon, and 116 (25.6%) with Vinblastine. Depending on both tumour size and location, patients were treated with extended cutaneous irradiation using 4 MeV electron beam energy and/or localized irradiation using 45–100 kV x-ray (cutaneous lesions), or 4 MV x-ray (oral tumours). A total of 5015 courses of radiation therapy was given. The intention of the treatment was closely linked to the anatomic sites. Multiple courses of treatment ranging from 10 to 20 Gy (2.5 Gy/fraction, 4 times/week) were used for Kaposi's sarcoma involving conjunctiva ( n = 32 treatments), eyelids ( n = 306), lips ( n = 170), hands ( n = 208), feet ( n = 417), penis ( n = 131), oral mucosa ( n = 43), and anal region ( n = 5). A second group including other cutaneous sites (face, trunk, limbs) was treated with a dose of 30 Gy (20 Gy in 2 weeks followed by 2 weeks rest and then a second series of 10 Gy in 1 week). Results : For the first group, tolerance was generally good excluding oral cavity irradiation, with an effective palliation of symptoms (87.8% overall rate of objective responses); an enhanced mucosal reactions was noted in patients receiving oropharyngeal irradiation. For the second group, a complete regression rate of 85% was observed; tolerance was acceptable: complications were severe epidermitis with skin ulceration (5%), exsudative epidermitis (26%), dry epidermitis (60%), and varying degrees of erythema (9%). There was a significant correlation between risk of recurrence (overall recurrence rate of 71% after an average of 7.5 months) and occurrence of opportunistic infections: 85% of recurrences appeared concomitantly with accelerated course of acquired immunodeficiency syndrome. Conclusions : We conclude that radiotherapy is an efficient treatment for epidemic Kaposi's sarcoma (EKS): doses of 15.2 Gy for oral lesions and 20 Gy for lesions involving conjunctiva, eyelids, lips, hands, feet, penis, and anal region were sufficient to produce shrinkage of the tumour and good palliation of symptoms. For the other cutaneous sites, 30 Gy local field irradiation could be safely given with better short-term response. Prophylactic measures with antifungal treatment should be systematically associated with oropharyngeal irradiation, to improve tolerance to the treatment.

Steroid treatment in active Crohn's disease: a comparison between two regimens of different duration

Steroids are highly effective in active Crohn's disease; clinical relapse following steroid withdrawal, however, is frequent. We used two steroid regimens of different duration in order to compare their efficacy in inducing and maintaining clinical remission. Seventy patients with active Crohn's disease were treated with methylprednisolone 40 mg/day i.m. for 3 weeks and then with two different regimens of tapering dosage: one for a further 4 weeks and another for a further 12 weeks. Steroid therapy induced remission within 3 weeks in 91% of the whole group of patients; at the end of each protocol remission rates were 85% of patients in the group treated for the shorter period and 87% of those treated for the longer period (difference 2%, CI = -14 to 18, P = NS); remission rates within 6 months after stopping steroids were 53% and 37% respectively (difference 16%, CI = -9 to 41, P = NS). No significant differences were found between the two regimens. Multiple courses of steroid treatment in the previous 3 years and a short time interval following previous steroid treatment seem to be risk factors for relapse.

Monitoring of ganciclovir sensitivity of multiple human cytomegalovirus strains coinfecting blood of an AIDS patient by an immediate-early antigen plaque assay

A plaque-reduction assay for chemosensitivity testing of human cytomegalovirus (HCMV) strains was developed based on early detection of viral plaques 96 h p.i. by a monoclonal antibody to the major immediate-early protein p72. Sequential HCMV isolates from an AIDS patient undergoing multiple courses of ganciclovir treatment during an 18-month follow-up were tested by the new assay, showing emergence of a ganciclovir-resistant strain. However, cloning of viral isolates and Southern blot hybridization analysis showed the simultaneous presence of three different HCMV strains in blood. Of these, the resistant strain was likely to be selected during prolonged maintenance antiviral treatment, emerging during full drug regimen, while the two sensitive strains reappeared in association with the resistant one following drug discontinuation. This finding was demonstrated by high levels of ID 90 and ID 99 in sequential mixed viral populations. The new plaque assay leads to reduction in time needed for chemosensitivity testing and permits rapid tracing of drug-resistant strains in a mixed viral population.

Retrospective Clinical Study of Hypersensitivity Reactions to Aztreonam and Six Other β-Lactam Antibiotics in Cystic Fibrosis Patients Receiving Multiple Treatment Courses

A total of 2,793 courses of treatment with seven beta-lactam antibiotics were administered to 121 cystic fibrosis patients chronically infected with Pseudomonas aeruginosa, and the patients were evaluated with respect to clinical hypersensitivity reactions. Seventy-five patients (62%) experienced 125 reactions, for an overall frequency (based on the number of courses) of 4.5%. Immediate reactions occurred in 34 patients (28.1%) during 53 courses (1.9%). The highest rate of reactions involved piperacillin (50.9% of patients), and the lowest rate involved imipenem and aztreonam (4.0% and 6.5% of patients, respectively); intermediate reaction rates were noted for carbenicillin (23.6% of patients), azlocillin (20.8%), cefsulodin (17.1%), and ceftazidime (13.0%). Cross-reactivity did not appear to be a major problem. Reactions to aztreonam seemed to be restricted to a small group of patients with a high propensity for beta-lactam hypersensitivity.

Evaluation of the Potential Role of Chelation Therapy in Treatment of Low to Moderate Lead Exposures

In the overall long-term management of lead poisoning, chelation therapy can have short-term benefits; however, these benefits must be accompanied by drastic reduction in environmental exposure to lead if therapy is to have any long-term benefit. This discussion is limited to calcium disodium ethylenediaminetetraacetate (CaNa2EDTA), the chelating agent that has been the mainstay of treatment of lead poisoning for the past 38 years, and to meso-2,3-dimercaptosuccinic acid (DMSA), a new and promising oral chelating agent, which is an orphan drug and is currently classified as an investigational new drug by the U.S. Food and Drug Administration. With both drugs, multiple courses of treatment will be needed if any substantial reduction in body lead burden is to be achieved. A major limitation of CaNa2EDTA is the enormous diuresis of zinc that it produces. DMSA produces a comparable diuresis of lead, a greater decrease in blood lead, and has negligible influence on the urinary losses of zinc, copper, iron, and calcium. Limited experience to date in man has revealed no significant adverse side effects of DMSA. In animals, DMSA will promptly reduce the concentration of lead in brain and kidney, in particular. By contrast, similar 5-day courses of CaNa2EDTA do not produce any net reduction in brain lead. This is important, as the brain is the critical organ of the adverse effects of lead in children. If the efficacy of DMSA is to be comprehensively evaluated ethically in children, new and more sensitive neurochemical, electrophysiologic, or other markers must be developed.

Evaluation of the potential role of chelation therapy in treatment of low to moderate lead exposures.

In the overall long-term management of lead poisoning, chelation therapy can have short-term benefits; however, these benefits must be accompanied by drastic reduction in environmental exposure to lead if therapy is to have any long-term benefit. This discussion is limited to calcium disodium ethylenediaminetetraacetate (CaNa2EDTA), the chelating agent that has been the mainstay of treatment of lead poisoning for the past 38 years, and to meso-2,3-dimercaptosuccinic acid (DMSA), a new and promising oral chelating agent, which is an orphan drug and is currently classified as an investigational new drug by the U.S. Food and Drug Administration. With both drugs, multiple courses of treatment will be needed if any substantial reduction in body lead burden is to be achieved. A major limitation of CaNa2EDTA is the enormous diuresis of zinc that it produces. DMSA produces a comparable diuresis of lead, a greater decrease in blood lead, and has negligible influence on the urinary losses of zinc, copper, iron, and calcium. Limited experience to date in man has revealed no significant adverse side effects of DMSA. In animals, DMSA will promptly reduce the concentration of lead in brain and kidney, in particular. By contrast, similar 5-day courses of CaNa2EDTA do not produce any net reduction in brain lead. This is important, as the brain is the critical organ of the adverse effects of lead in children. If the efficacy of DMSA is to be comprehensively evaluated ethically in children, new and more sensitive neurochemical, electrophysiologic, or other markers must be developed.

In Vitro and In Vivo Hematopoietic Effect of Mutant Human Granulocyte Colony-Stimulating Factor

About 100 derivatives of human recombinant granulocyte colony-stimulating factor (rhG-CSF) were created by various gene-mutagenic techniques, and KW-2228, in which amino acids were replaced at five positions of N-terminal region of intact rhG-CSF, was picked up and evaluated for its biologic and physicochemical properties in comparison with intact rhG-CSF. KW-2228 showed two to four times higher specific activity than that of intact rhG-CSF in mouse and/or human bone marrow progenitor cells by colony-forming unit assay in soft agar, and by cell-proliferation assay in liquid culture. KW-2228 showed a potency to increase peripheral neutrophil counts when it was administered to normal C3H/He mice by single intravenous injection. Increase of total leukocyte count and neutrophils was observed, with peak level at 8 to 12 hours at low doses (0.5 to 1.0 micrograms/mouse), and the highest level was maintained for 24 to 30 hours at high doses (5 to 10 micrograms/mouse). The granulopoietic effect of KW-2228 was examined by several doses of single course (once daily for 10 days) or multiple courses (twice daily injection for 5 days followed by cessation for 9 days on one cycle, 3 cycles in total) of treatment. KW-2228 showed higher activity than that of rhG-CSF, especially at sub-optimal doses of multiple courses of treatment. Furthermore, KW-2228 was found to be more stable physicochemically and biologically than intact rhG-CSF, especially under thermal conditions at 56 degrees C and in the human plasma at 37 degrees C, suggesting a protease resistancy. Pharmacokinetic study showed that plasma concentration of KW-2228 assayed for its bioactivity maintained a higher level than that of intact rhG-CSF for 60 minutes after intravenous injection of this protein to normal mice. Those results suggest that KW-2228 might show a superior in vivo hematopoietic effect to intact rhG-CSF due to its high specific activity to progenitor cells, and also due to its improved physicochemical, biologic, and pharmacokinetic stability in host animals.