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.     

Phase 1/2 study of the combination of 5-aza-2'-deoxycytidine with valproic acid in patients with leukemia

We conducted a phase 1/2 study of the combination of 5-aza-2'-deoxycytidine (decitabine) and the histone deacetylase inhibitor valproic acid (VPA) in patients with advanced leukemia, including older untreated patients. A group of 54 patients were treated with a fixed dose of decitabine (15 mg/m(2) by IV daily for 10 days) administered concomitantly with escalating doses of VPA orally for 10 days. A 50 mg/kg daily dose of VPA was found to be safe. Twelve (22%) patients had objective response, including 10 (19%) complete remissions (CRs), and 2 (3%) CRs with incomplete platelet recovery (CRp). Among 10 elderly patients with acute myelogenous leukemia or myelodysplastic syndrome, 5 (50%) had a response (4CRs, 1CRp's). Induction mortality was observed in 1 (2%) patient. Major cytogenetic response was documented in 6 of 8 responders. Remission duration was 7.2 months (range, 1.3-12.6+ months). Overall survival was 15.3 months (range, 4.6-20.2+ months) in responders. Transient DNA hypomethylation and global histone H3 and H4 acetylation were induced, and were associated with p15 reactivation. Patients with lower pretreatment levels of p15 methylation had a significantly higher response rate. In summary, this combination of epigenetic therapy in leukemia was safe and active, and was associated with transient reversal of aberrant epigenetic marks.     

Use of peripheral blood blasts vs bone marrow blasts for diagnosis of acute leukemia.

Acute leukemia can be diagnosed when blasts constitute 30% or more of the nucleated cells in a patient's peripheral blood (PB) sample. To determine whether in such cases bone marrow (BM) aspirates are still necessary, we compared the results of diagnostic studies performed on PB samples with blast counts of 30% or more with those performed on the same patients' BM samples. We found no differences in morphologic features, cytochemistry, or immunophenotype between the blasts in PB and BM samples in any of 30 cases studied. However, in 10 (23%) of 44 cases in which cytogenetic analysis was performed, PB but not BM samples were insufficient for analysis. The converse never occurred. Five of the 10 cases had acute lymphoblastic leukemia and 5 had acute myeloid leukemia (41% of the patients with acute lymphoblastic leukemia and 17% of the patients with acute myeloid leukemia). In cases with adequate metaphases, there was strong correlation between the cytogenetic results for PB and BM samples. Some PB samples with blast counts of 30% or more are adequate for diagnosis of acute leukemia, especially when therapy can be delayed until it is known that an adequate number of analyzable metaphases are recovered from the PB samples.     

Comparison of touch imprints with aspirate smears for evaluating bone marrow specimens.

We compared the differential counts of normal and abnormal bone marrow from touch imprints with those from aspirate smears to determine whether the touch imprint was reliable for independent routine use in the examination of bone marrow and the classification of hematologic abnormalities. Normocellular bone marrow specimens were obtained from 87 patients without hematologic abnormality. Abnormal bone marrow specimens were obtained from 173 patients with treated or untreated neoplastic hematologic disease, including acute myeloid leukemia, myelodysplastic syndrome, chronic lymphocytic leukemia, non-Hodgkin lymphoma, hairy cell leukemia, myeloma, and acute lymphoblastic leukemia. We found no diagnostic difference in the differential counts from touch imprints and aspirate smears of normocellular bone marrow, and although we found some difference between the differential counts in certain cases of diseased bone marrow, the touch imprint proved to be a reliable diagnostic tool for determining the cellular composition of normal bone marrow and more reliable for the diagnosis of bone marrow involved by a neoplastic hematologic disease. Our findings suggest that evaluating touch imprints should be considered a standard practice in examining bone marrow.     

Accounting for patient heterogeneity in phase II clinical trials

Phase II clinical trials typically are single-arm studies conducted to decide whether an experimental treatment is sufficiently promising, relative to standard treatment, to warrant further investigation. Many methods exist for conducting phase II trials under the assumption that patients are homogeneous. In the presence of patient heterogeneity, however, these designs are likely to draw incorrect conclusions. We propose a class of model-based Bayesian designs for single-arm phase II trials with a binary or time-to-event outcome and two or more prognostic subgroups. The designs' early stopping rules are subgroup specific and allow the possibility of terminating some subgroups while continuing others, thus providing superior results when compared with designs that ignore treatment-subgroup interactions. Because our formulation requires informative priors on standard treatment parameters and subgroup main effects, and non-informative priors on experimental treatment parameters and treatment-subgroup interactions, we provide an algorithm for computing prior hyperparameter values. A simulation study is presented and the method is illustrated by a chemotherapy trial in acute leukemia.     

A New Statistical Method for Dose-Finding Based on Efficacy and Toxicity in Early Phase Clinical Trials

Most statistical methods for dose-finding in phase I clinical trials determine a maximum tolerable dose based on toxicity while ignoring efficacy. Most phase II designs assume that an acceptable dose has been determined and aim to estimate treatment efficacy, possibly with early stopping rules for safety monitoring. The purpose of this paper is to describe a new statistical strategy for dose-finding in single-arm clinical trials where patient outcome is characterized in terms of both response and toxicity. The strategy, which may be considered a phase I/II hybrid, was first proposed by Thall and Russell [1] and subsequently modified by Thall [2]. The underlying mathematical model expresses the probabilities of response and toxicity as interdependent functions of dose. The method is based on fixed standards for the minimum probability of response and the maximum probability of toxicity appropriate for the particular trial. The best acceptable dose is chosen for each successive patient cohort adaptively, based on the fixed standards and the dose-outcome data from patients treated previously in the trial. The scientific goals are to select one best acceptable dose for future patients and to estimate the response and toxicity probabilities at that dose, or to stop the trial early if it becomes sufficiently unlikely that any dose is both safe and efficacious. An application of the method to a trial of donor lymphocyte infusion as salvage therapy for chemo-refractory AML/MDS patients is described. To illustrate the method's flexibility and potential breadth of application, two additional examples are provided, including a hypothetical trial in which a 5% response rate is of interest.     

Less apoptosis in patients with 5q-syndrome than in patients with refractory anemia

The WHO classification of hematological malignancies includes 5q-syndrome as a separate category within myelodysplastic syndromes (MDS). Clinically, patients with 5q-syndrome have a milder disease than patients with other MDS. The basis for this difference is not known. Identifying 5q-syndrome can be difficult because some of its morphologic and cytogenetic features are similar to those of other MDS. We compared apoptosis between 5q-syndrome and other refractory anemias. We found lower levels of apoptosis in 5q-syndrome as detected by less disruption of mitochondrial potential (P=0.008) and decreased annexin V positivity (P=0.01). Our results suggest that lower apoptosis in 5q-syndrome may explain the milder clinical course of the disease and distinguish 5q-syndrome from other MDS.     

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.