Response in acute myeloid leukemia

For many years, response to induction therapy in acute myeloid leukemia was classified as "complete response" (CR) or "no CR." The emphasis on CR reflected the proven ability of CR to extend survival, the outcome of primary interest to patients. Beginning with the adoption of complete response with incomplete platelet recovery (CRp), recent years have seen the acceptance of responses less than CR as beneficial. Although these responses denote that a drug is active, relatively little attention has been paid to the effect of such responses on survival. This article explores the effect of such responses on survival.     

Effects of solution conditions and surface chemistry on the adsorption of three recombinant botulinum neurotoxin antigens to aluminum salt adjuvants

Botulinum neurotoxin (BoNT) is a biological warfare threat. Protein antigens have been developed against the seven major BoNT serotypes for the development of a recombinant protein vaccine. This study is an evaluation of adsorption profiles for three of the recombinant protein antigens to aluminum salt adjuvants in the development of a trivalent vaccine against BoNT. Adsorption profiles were obtained over a range of protein concentrations. The results document that charge-charge interactions dominate the adsorption of antigen to adjuvant. Optimal conditions for adsorption were determined. However, potency studies and solution stability studies indicated the necessity of using aluminum hydroxide adjuvant at low pH. To improve the adsorption profiles to AlOH adjuvant, phosphate ions were introduced into the adsorption buffers. The resulting change in the adjuvant chemistry led to an improvement of adsorption of the BoNT antigens to aluminum hydroxide adjuvant while maintaining potency. Competitive adsorption profiles were also determined, and showed changes in maximum adsorption from mixed solutions compared to adsorption from individual protein solutions. The adsorption profiles for each protein varied due to differences in adsorption mechanism and affinity for the adjuvant surface. These results emphasize the importance of evaluating competitive adsorption in the development of multivalent vaccine products.     

Altered conformation of the p53 protein in myeloid leukemia cells and mitogen-stimulated normal blood cells.

Expression of the normal p53 gene promotes cell differentiation, maturation and apoptosis. The mutant p53 gene, which does not function normally, is frequently expressed at elevated levels in tumor cells [for review see Lane, D.P. & Benchimol, S. (1990). Genes Dev., 4, 1-8]. We have analysed the expression of and mutational change in the p53 gene in the peripheral blood cells of 49 primary acute myeloid leukemia (AML) patients. The p53 protein levels were elevated in 37 patients (75%) when measured by immunoprecipitation with antibodies PAb1801 and PAb421, which recognize both normal and mutant forms of the protein. The p53 protein from 32 of these 37 patients was immunoprecipitated by PAb240, which recognizes a conformation of p53 protein associated with point mutations. However, point mutations were detected by single-stranded conformation polymorphism (SSCP) assay and direct sequencing in only three patients at codons 178, 245, 273 and 290. Growth stimulation of normal lymphocytes also generated p53 which was immunoprecipitable by PAb240. Thus, alteration of p53 conformation, rather than acquisition of point mutations, could be the mechanism underlying the increased proliferation of myeloid cells in most AML patients.     

Treatment of advanced stages of Philadelphia chromosome-positive chronic myelogenous leukemia with interferon-alpha and low-dose cytarabine.

PURPOSE: To evaluate the efficacy of interferon-alpha (IFN-A) and low-dose cytarabine (ara-C) combination chemotherapy in patients with chronic myelogenous leukemia (CML). PATIENTS AND METHODS: Sixty patients with advanced phases of Philadelphia chromosome (Ph)-positive CML received combination therapy with IFN-A 5 x 10(6) U/m2 daily, and low-dose ara-C 15 mg/m2 daily for 2 weeks every 4 weeks until remission, then for 1 week every month as maintenance. Forty patients were in late chronic-phase CML, and 20 were in accelerated-phase CML (16 with clonal evolution only, four with other criteria). Their outcome was compared with 58 patients (39 late chronic-phase CML and 19 accelerated-phase CML) who had been previously treated with IFN-A alone in the same dose schedule. RESULTS: In late chronic-phase CML, patients receiving IFN-A plus ara-C had a better complete hematologic response (CHR) rate compared with those treated with IFN-A alone (55% v 28%; P = .02), a trend for better Ph suppression (15% v 5%; P = .13), and a longer survival (3-year survival rate 75% v 48%; P less than .01). These differences do not seem to be caused by imbalances in prognostic factors between the two treatment groups. In accelerated-phase CML, the addition of ara-C to IFN-A did not improve the response rate of treated patients, and the difference in survival was accounted for by different patient characteristics. Suppression of clonal evolution was observed in five patients (25%). Patients with clonal evolution as the only criterion for disease acceleration had a longer survival than those with other or additional accelerated-phase criteria (3-year survival rate 67% v 22%; P less than .01). CONCLUSION: The results with the combination of IFN-A plus ara-C in late chronic-phase CML are encouraging, and suggest the need for its evaluation in early chronic-phase CML.     

Major Neurological Disease and Occupational Exposure to Organic Solvents

Five patients are described who presented with major organicbrain disease affecting one or more of pyramidal and extrapyramidaltracts, cerebellum, and higher cortical functions. All had ahistory of 10 years or more of regular occupational exposureto solvents in confined spaces, three in painting inside shipsand the others in weapons maintenance and printing. All hadbeen regularly exposed to high air vapour peaks as well as toskin contamination. Four showed some evidence of improvementafter the exposure ceased. None was initially suspected of havinga toxic encephalopathy by the consultant to whom he was referred.The spectrum of neurological disease presented by these menmirrors closely that described in solvent abusers. All wereforced by illness to retire from their work, a circumstancewhich might have in the past have led to such conditions beingmissed in cross-sectional studies, which in general have notshown evidence of major disease. We suggest that when such diseaseoccurs nowadays, its cause is usually not suspected. Furtherepidemiological study of the problem is necessary.     

A strategy for evaluation of new treatments in untreated patients: application to a clinical trial of AMSA for acute leukemia

This clinical trial (DT7995) was designed to evaluate amsacrine (AMSA) plus cytosine arabinoside (ara-C), vincristine, and prednisone (OAP) therapy in previously untreated patients with adult acute leukemia and to investigate a new strategy for assignment of patients to treatment using estimated probabilities of complete remission (PPR) based on six prognostic factors. In the first stage of the trial, patients with unfavorable prognosis (PPR less than .40) received AMSA-OAP for remission induction and patients with favorable prognosis (PPR greater than or equal to .40) received Adriamycin [Adria Laboratories, Columbus, OH] plus OAP (Ad-OAP). As AMSA-OAP was found to be promising in patients with unfavorable prognosis, it was administered to relatively more favorable patients (PPR less than .60) in the second stage of the trial and to all patients in the third stage. There were 242 patients entered into study; 134 received AMSA-OAP and 108 received Ad-OAP. Outcomes were compared with 242 paired patients who received Ad-OAP therapy from 1973 to 1977. The estimated complete remission rate in previously untreated adults with acute leukemia is 61% for patients receiving Ad-OAP (95% confidence interval, 59% to 64%). Overall, the survival experience for the 242 patients on DT7995 was significantly better than that in the control series (P = .03), but there was no strong statistical evidence (P = .10) that the 134 patients receiving AMSA-OAP had better survival than control patients receiving Ad-OAP, with a median of 32 v 21 weeks, respectively. It is concluded that AMSA-OAP is equivalent to Ad-OAP in the induction of complete remissions (estimated complete remission rate, 61%) and that assignment of patients to treatment based on predicted prognosis is an ethical and efficient strategy for the evaluation of new therapies in previously untreated patients with acute leukemia.