Electronic residency application service scores: do they correlate with the rank order list for the match?

OBJECTIVE

To investigate the relationship between ERAS-based preinterview scores, residency program postinterview scores and candidate rank order for the match.

STUDY DESIGN

Two hundred sixty-three candidates' preinterview and postinterview scores and rank order were evaluated. The rank order was stratified as 1-4, 5-8, 9-12, > 13 and unranked. Spearman's p statistical analysis was used.

RESULTS

There was a moderate relationship, r2 = 0.543, between preinterview and postinterview scores for all applicants. There was a significant inverse correlation between preinterview score and rank order, r2 = -0.763, and for the postinterview and rank order, r2 = -0.768. However, there were no significant relationships between factors significant for the top 4 ranked candidates.

CONCLUSION

Preinterview and postinterview scores significantly correlated with each other and with the rank order list except for top-ranked candidates. Other factors may influence the rank order list.

How do medical student self-assessments compare with their final clerkship grades?

The purpose of this study was to determine how a medical student's self-assessment at the completion of the third-year Ob/gyn clerkship compares with the institution's final grades at Lehigh Valley Hospital. From November 2002 to November 2003 at completion of each six-week Ob/gyn clerkship rotation, 47 medical students assessed themselves on the following parameters: fund of knowledge, personal attitude, clinical problem-solving skills, written/verbal skills, and technical skills. Additionally, they were asked to predict their performance on the NBME Shelf Exam. Their assessments were then compared with their final clerkship grades in each of the above parameters. Chi-squared and Kendall-tau tests were used to analyse the data for degree of agreement and association, respectively. There was a statistically significant weak to moderate, positive correlation between students' self-assessment and final clerkship grade for written/verbal skills (p = 0.002, r = 0.390). A statistically significant agreement between raters was also revealed for written/verbal skills (p = 0.003). Weak, non-statistically significant, positive relationships were revealed for fund of knowledge, clinical problem-solving and technical skills. A weak, negative, non-significant relationship was revealed for personal attitudes, and there was no statistically significant relationship between students' prediction of NBME score and categorized true score (p = 0.717, r = 0.49). At the end of their Ob/gyn clerkship, third-year medical students are better at assessing their technical and written/verbal skills than their global fund of knowledge and personal attitudes. These results may suggest that students are not aware of their own personal attitudes and communication skills and how they can affect their effectiveness as a physician.

High-dose chemotherapy in high-risk myelodysplastic syndrome: covariate-adjusted comparison of five regimens

BACKGROUND

Antileukemic chemotherapy has been used for two decades to treat high-risk myelodysplastic syndrome (refractory anemia with excess of blasts [RAEB] and RAEB in transformation into acute leukemia [RAEB-t]) patients. Because the results of standard regimens have been disappointing, high-dose chemotherapeutic regimens were investigated recently. In the absence of randomized trials, the relative merits of various treatment regimens are unknown.

METHODS

The authors analyzed the outcome for 394 newly diagnosed patients treated between 1991 and 1999 with five regimens consisting of intermediate- or high-dose cytosine arabinoside (A) in combination with idarubicin (I), and introduced cyclophosphamide (C) and the new agents fludarabine (F) and topotecan (T) into new combinations with A. In addition to defining the role of high-intensity chemotherapy in the overall outcome for patients with RAEB-t and RAEB, the authors determined the relative merits of the five regimens (IA, FA, FAI, TA, and CAT), accounting for the nonrandom distribution of the prognostic covariates.

RESULTS

The overall complete response (CR) rate of 58% was significantly associated with karyotype, performance status (PS), treatment in the laminar air flow room, duration of antecedent hematologic disorder and age, but not French-American-British or International Prognostic Scoring System risk categories. Multivariate analysis did not identify statistically significant differences in CR rates obtained with each regimen. Induction death rates increased with age with all but the TA regimen; they were lowest with TA (5.4%) and highest with FAI (20.7%), and these differences were significant in patients older than 65 years. The trend for time to death was the same as for time to recurrence in all groups. Multivariate analysis of time to death identified treatment regimen (FA, FAI, and CAT), cytogenetic status (-5/-7), increasing age, and PS greater than 2 as significant independent unfavorable prognostic factors. After prognostic variables were accounted for, survival with IA treatment remained superior to that of FA and FAI but comparable to TA, and CR duration was only marginally shorter with FA. Landmark analysis showed the overall survival of responders to be superior to that of nonresponders, the difference remaining significant after adjustment for prognostic covariates.

CONCLUSIONS

Although the newer regimens did not improve outcome, TA and CAT produced results comparable to those of IA and may be considered treatment alternatives. The TA regimen was particularly effective in RAEB patients and could be delivered safely, with low induction mortality. Our results indicated that although CR seemed associated with survival advantage, innovative post-remission managements represent a challenge because improvement in outcome is not likely to come from intensified therapy.

"T-cell-rich B-cell lymphoproliferative disorder" of the bone marrow

We report four cases of a "T-cell-rich B-cell chronic lymphoproliferative disorder" involving the bone marrow and not extramedullary sites. The neoplastic B-cell proliferation in these cases was composed predominantly of small lymphoid cells with features of both hairy cell leukemia and lymphoplasmacytoid lymphoma. All cases presented with neutropenia and with difficulty in diagnosis. We present the clinical, morphologic, cytochemical, and immunophenotypic findings in these cases and discuss this entity.

Results of the fludarabine and cyclophosphamide combination regimen in chronic lymphocytic leukemia

PURPOSE

To assess the efficacy of combination therapy with fludarabine and cyclophosphamide in patients with chronic lymphocytic leukemia (CLL) based on data suggesting in vitro synergistic activity of the two agents.

PATIENTS AND METHODS

A total of 128 patients with CLL were treated with fludarabine 30 mg/m(2) intravenously daily for 3 days and cyclophosphamide at either 500 mg/m(2) daily for 3 days (n = 11), 350 mg/m(2)/d for 3 days (n = 26), or 300 mg/m(2) daily for 3 days (n = 91). The cyclophosphamide dose was decreased because of myelosuppression in the early part of the study. Patients were divided into four groups based on the expectation for response to single-agent fludarabine, including previously untreated patients, patients previously treated with alkylating agents, patients successfully treated with alkylating agents and fludarabine but relapsing, and patients refractory to fludarabine with or without alkylating agents.

RESULTS

Fludarabine and cyclophosphamide produced > or = 80% response rates in all patients not refractory to fludarabine at the start of therapy as well as a 38% response rate in patients who were refractory to fludarabine. The complete remission (CR) rate was 35% in previously untreated patients, which was not significantly different from the CR rate in historical control patients treated with single-agent fludarabine. However, residual disease assessed by flow cytometry occurred in only 8% of previously untreated patients achieving CR, and median time to progression has not been reached after a median follow-up of 41 months. The main complication of therapy was related to myelosuppression and infection. Neutropenia to less than 500 x 10(9)/L was noted in 48% of patients who received cyclophosphamide 300 mg/m(2). Pneumonia or sepsis occurred in 25% of patients, and fever of unknown origin occurred in another 25%. Pneumonia or sepsis were significantly more frequent in patients who were refractory to fludarabine at the start of combination chemotherapy.

CONCLUSION

Fludarabine and cyclophosphamide seem to have a significant advantage over single-agent fludarabine in the salvage setting. Although the CR rate was not increased in previously untreated patients, residual disease detected by flow cytometry was rare and remission durations seemed to be prolonged in this subset. Myelosuppression and infection remain the most significant complications of therapy in CLL.

Chronic myelogenous leukemia in nonlymphoid blastic phase: analysis of the results of first salvage therapy with three different treatment approaches for 162 patients

BACKGROUND

The prognoses of patients with chronic myelogenous leukemia in blastic phase (CML-BP) are extremely poor. Treatment of patients with nonlymphoid CML-BP is associated with very low response rates, a median survival of 2-3 months, and significant toxicities. The aim of this study was to evaluate the results of therapy in CML-BP with different treatments in relation to response rate, survival, and toxicity.

METHODS

A total of 162 adults patients with a diagnosis of nonlymphoid CML-BP referred from 1986 to 1997 were included in this analysis. Only first salvage therapy was considered for the purpose of this analysis. The blastic phase of CML was defined by the presence of 30% or more blasts in the blood or bone marrow, or extramedullary disease. Ninety patients were treated with intensive chemotherapy, 31 with decitabine, and 41 with other single agents.

RESULTS

Thirty-six patients (22%) had an objective response. Response rates were similar among patients treated with intensive chemotherapy (28%) or with decitabine (26%). In aggregate, other single agents showed objective response rates of 7%. The median duration of remission for all patients was 29 weeks and the median overall survival 22 weeks. Patients treated with decitabine showed a trend toward better survival, despite a higher percentage of older patients (P < 0.004). The median survival times were 29 weeks with decitabine, 21 weeks with intensive chemotherapy, and 22 weeks with other agents. When only older patients were considered, survival was significantly better with decitabine versus other treatments (P < 0.01). A multivariate analysis of prognostic factors for survival confirmed the independent, significant favorable effect of decitabine therapy (P = 0.047). In all groups complications of myelosuppression were the most significant side effects. Severe nonhematologic toxicities were not observed in patients treated with decitabine; they occurred in 20% and 17% of patients treated with intensive chemotherapy or other single agents, respectively.

CONCLUSIONS

Compared with intensive chemotherapy, decitabine showed favorable results, with similar objective response rates, a better nonhematologic toxicity profile, and a trend for better survival, particularly among older patients. Studies will now attempt to combine decitabine with other promising approaches, such as homoharringtonine, low dose cytarabine, and interferon-alpha, in all CML phases.

A phase I-II trial of escalating doses of mitoxantrone with fixed doses of cytarabine plus fludarabine as salvage therapy for patients with acute leukemia and the blastic phase of chronic myelogenous leukemia

BACKGROUND

Cytarabine is an essential drug for inducing remission of acute myelogenous leukemia, and it is also one the most effective drugs used as salvage therapy for patients with all types of relapsed acute leukemia. Nevertheless, there is considerable room for improvement in the treatment of patients with relapsed leukemia in terms of both the reinduction rate and the duration of response. Fludarabine has been shown to augment responses to cytarabine, possibly by increasing the intracellular concentrations of the active metabolite cytarabine triphosphate. Higher-than-standard doses of mitoxantrone have been shown to augment responses to cytarabine, possibly by increasing the DNA strand breaks induced by topoisomerase II; these strand breaks cannot be effectively repaired in the presence of cytarabine triphosphate. This preliminary study was designed to determine whether moderately high doses of mitoxantrone could be added to the combination of fludarabine and cytarabine in an attempt to improve the combination's antileukemic efficacy.

METHODS

Fifty-five adults with relapsed or refractory acute leukemia or the blastic phase of chronic myelogenous leukemia (CML) received salvage therapy with the FLAM regimen, which consisted of fludarabine, cytarabine, and increasing doses of mitoxantrone.

RESULTS

Even with doses of mitoxantrone escalated to as much as 60 mg/m(2) over 4 days, dose-limiting toxicity was not observed. Overall, the complete response rate was 27.3% (15 of 55 patients, including 4 of 17 with acute myelogenous leukemia [AML], 4 of 12 with acute lymphocytic leukemia [ALL], and 7 of 26 with the blastic phase of CML). The median time to complete response was 42 days. Toxicity other than myelosuppression was manifested primarily as hyperbilirubinemia, which was reversible in all cases. Poor performance status and undifferentiated blastic phase of CML were poor prognostic factors for response to FLAM.

CONCLUSIONS

The FLAM regimen is an active salvage regimen and should be formally evaluated in Phase II studies of patients with AML, ALL, and the myeloid and lymphoid blastic phases of CML.

Topotecan and cytarabine is an active combination regimen in myelodysplastic syndromes and chronic myelomonocytic leukemia

PURPOSE

To evaluate the efficacy and safety of the combination of topotecan and cytarabine in patients with myelodysplastic syndromes (MDSs) and chronic myelomonocytic leukemia (CMML).

PATIENTS AND METHODS

Fifty-nine patients with MDSs and 27 with CMML were enrolled. They were either previously untreated (66%) or had received only biologic agents (14%) or chemotherapy with or without biologic agents (20%). Treatment consisted of topotecan 1.25 mg/m(2) by continuous intravenous infusion daily for 5 days and cytarabine 1. 0 g/m(2) by infusion over 2 hours daily for 5 days. Prophylaxis included antibacterial, antifungal, and antiviral agents. At a median follow-up of 7 months, all 86 patients were assessable for response and toxicity.

RESULTS

Complete remission (CR) was observed in 48 patients (56%; 61% with MDSs, 44% with CMML; P =.15). Similar CR rates were observed for patients with good-risk and poor-risk MDS (70% and 56%, respectively). The treatment effectively induced CR in patients with a poor-prognosis karyotype involving chromosomes 5 and 7 (CR, 71%) and secondary MDSs (CR, 72%). Fifty-four patients received one induction course, 25 patients received two, and the rest received more than two. The median number of continuation courses was two. The median overall duration of CR was 34 weeks (50 weeks for MDSs and 33 weeks for CMML). The median survival was 60 weeks for MDS and 44 weeks for CMML patients. CR and survival durations were longer in patients with refractory anemia with excess blasts (RAEB). Grade 3 or 4 mucositis or diarrhea was observed in three patients each. Fever was observed in 63%, and infections in 49% of patients. Six patients (7%) died during induction therapy.

CONCLUSION

Topotecan and cytarabine induced high CR rates in unselected patients with MDSs and CMML, particularly among patients with poor-prognosis cytogenetics and secondary MDSs. Topotecan-cytarabine is an active induction regimen in MDS and CMML patients, is well tolerated, and is associated with a low mortality rate.

Role of radiation therapy to the brain in leukemic patients with cranial nerve palsies in the absence of radiological findings

The value of brain radiotherapy for leukemic patients with cranial nerve palsies in the absence of radiological evidence of leukemic infiltration is not well defined. This retrospective study was undertaken to evaluate the effectiveness of brain irradiation in reversing the cranial nerve palsies in leukemic patients with no radiological evidence of intracranial leukemic infiltration. Records of leukemic patients who received brain radiotherapy between June 1980 and December 1993 were reviewed. Criteria for inclusion were 1) no evidence of intracranial leukemic infiltration by computed axial tomography (CT) or magnetic resonance imaging scan (MRI), 2) no evidence of leukemic infiltration on ophthalmologic examination, and 3) no previous radiotherapy to the brain. Actuarial survival rates were calculated using the Kaplan-Meier method. Pearson's chi-squared test was used to compare responses. Twenty-eight patients met these criteria. The median age was 38 years (range 3-75 years): Seventeen patients had acute lymphoblastic leukemia, nine had acute myelogenous leukemia, and two had chronic myelogenous leukemia. Four patients had initial presentation with leukemia, and 24 presented with relapse. Twenty-six patients had cerebrospinal fluid cytology that was positive for leukemic cells. Fifteen patients had involvement of more than one cranial nerve, and nine had bilateral involvement. The most commonly involved nerves were the facial (n = 18), oculomotor (n = 9), and abducens nerves (n = 8). Twenty-six patients received whole-brain radiotherapy. Two received radiation to the base of the skull only. The median radiation dose was 24 Gy (range 16-30 Gy) at 2-3 Gy per fraction. Every patient had either concomitant intrathecal (n = 6) or systemic (n = 5) chemotherapy or both (n = 17) with radiation. Fourteen patients had complete reversal of the cranial nerve deficit, eight had partial recovery, and four had no response or progression of the disease. The response was unknown in two patients. Factors associated with complete response were unilateral versus bilateral involvement (72% vs. 13%, P = 0.005) and single versus multiple nerve involvement (75% vs. 36%, P = 0.045). In conclusion, radiation therapy to whole brain was effective in reversing cranial nerve deficits from leukemia, although the leukemic infiltration may not be visualized by CT or MRI. No dose-response relationship was observed in the range we examined.

Primary myeloid leukemia presenting concomitantly with primary multiple myeloma: two cases and an update of the literature

We report one case of primary acute myelogenous leukemia (AML) and one case of refractory anemia with excess blasts in transformation (RAEB-T) each presenting concomitantly with multiple myeloma, an unusual finding. The twin diagnoses in each patient were confirmed by cytochemical and immunohistochemical studies, and in one of our cases, by ultrastructural, flow cytometric, and molecular studies. The last three methods have not been previously used to document this phenomenon.

Results of topotecan single-agent therapy in patients with myelodysplastic syndromes and chronic myelomonocytic leukemia

The activity of topotecan was evaluated in patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). Sixty patients with a diagnosis of MDS (n = 30) or CMML (n = 30) were treated. Their median age was 66 years, with 50 patients (83%) being over 60 years of age at time of study entry. Chromosomal abnormalities were present in 50% of patients and thrombocytopenia of less than 50 x 10(9)/L in 50%. Topotecan was administered as 2 mg/m2 by continuous infusion over 24 hours daily for five days (10 mg/m2 per course) every 4 to 6 weeks for two courses, then at maximum tolerated dose level (1-2 mg/m2 by continuous infusion over 24 hours daily for five days) once every 4-8 weeks for a maximum of 12 courses. Evaluation of outcome and of differences among subgroups was performed according to standard methods; the criteria for response were those used for acute leukemia. Nineteen patients (31%) achieved a complete response (CR). A CR was achieved in 11 of 30 patients with MDS (37%) and in eight of 30 with CMML (27%). A CR was achieved in 10 of 23 patients with previously untreated MDS (43%). Eight of 11 patients who presented with cytogenetic abnormalities (five of which involved chromosome 5 and/or 7 abnormalities) and achieved CR, were evaluated cytogenetically in CR: all were cytogenetically normal in CR. Characteristics associated with a higher CR rate were lack of previous chemotherapy, absence of ras oncogene mutations, and presence of less than 10% monocytes in either peripheral blood or bone marrow. In contrast, CR rates were similar by different agent groups, by different karyotype abnormalities, and by other pre-therapy peripheral blood counts. Non-myelosuppressive side effects were mucositis in 67% of patients (severe [grade 3-4] 23%), diarrhea in 38% (severe 17%), and nausea and vomiting in 28% (severe 5%). Febrile episodes during neutropenia occurred in 85% of patients and documented infections in 47 %. Mortality in the first four weeks was 20%. With a median follow-up duration of 31 months, the 12 month survival rate was 38%, median survival time 10.5 months, and median remission duration 7.5 months. In summary, topotecan has significant single-agent activity in MDS and CMML. Complete responses associated with topotecan therapy often involve the disappearance of abnormal, poor-prognosis karyotypes, which is particularly encouraging. Future strategies to optimize topotecan's role include combination regimens with topoisomerase II reactive agents, cytarabine, or hypomethylating agents (azacytidine and decitabine).

CECA-cyclophosphamide, etoposide, carboplatin and cytosine arabinoside--a new salvage regimen for relapsed or refractory acute myelogenous leukemia

In an effort to develop more effective therapy for patients with refractory or relapsed acute myelogenous leukemia (R-AML) we combined three drugs with proven activity in AML, that are not typically used in induction regimens, with cytosine arabinoside (ara-C). Twenty-five patients (3 primary refractory, 22 relapsed) were treated. Patients received 3 days of "CECA" therapy as follows: cyclophosphamide (CTX) 1 g/m2 i.v. over 2 hrs., etoposide (VP-16) 200 mg/m2 i.v. over 3 hr, carboplatin (CBP) 150 mg/m2 i.v. over 24 hours and ara-C 1 g/m2 over 2 hr. Peripheral circulating blasts cleared in 24 cases (96%), and marrow aplasia was achieved in 19 (76%). There were 3 complete remissions (CR), 1 patient died before day 14, 5 died aplastic 14 or more days from the start of therapy, 5 had primary resistant disease, and 10 had secondary resistance i.e., leukemia reappearing after developing aplasia and 1 was lost to follow up 6 weeks into therapy. Two of the patients achieving CR received allogeneic BMT in CR (at 18 and 22 weeks): one died of fungal infection on day 50 and the other, who had CNS involvement at relapse, is alive 24 months post transplant. Toxicity was tolerable: one patient each developed grade III diarrhea and mucositis, another had grade III cardiac toxicity, a fourth developed a grade IV bilirubin elevation. Single, 2, and 3 or more infectious episodes occurred in 10, 5 and 4 patients respectively. This regimen showed definite anti-leukemic activity: the 3 patients achieving CR were among 23 patients with a 1%, 10% or 20% expectation for second CR attainment. The CECA regimen should be investigated in better prognosis salvage groups.

The hyper-CVAD regimen improves outcome in relapsed acute lymphoblastic leukemia

Sixty-six adults with refractory acute lymphocytic leukemia received salvage therapy with the 'hyper-CVAD' regimen, consisting of eight courses of alternating intensive chemotherapy with growth factor support, followed by oral maintenance chemotherapy. Their outcome was compared with 63 prognostically similar historical control patients treated with high-dose Ara-C plus mitoxantrone with or without GM-CSF. Overall, the complete response rates were similar in the treatment and control groups (29 of 66 (44%) vs 24 of 63 (38%)). There were more patients in the current study with primary resistant disease (10 of 66 (15%) vs one of 63 (2%), P = 0.006), and conversely fewer patients with secondary resistance (19 of 66 (29%) vs 28 of 63 (44%), P = 0.06). Recovery of granulocyte counts above 500/microl was significantly faster in the current study when compared to high-dose Ara-C-treated patients who were given GM-CSF (20 vs 25 days, P = 0.04). Survival was prolonged in the hyper-CVAD-treated patients, with most of the benefit seen in first salvage patients (42 vs 20 weeks, P = 0.016). When only first salvage patients were considered, there was a significant difference in disease-free survival in favor of hyper-CVAD (52 vs 20 weeks, P = 0.008). The hyper-CVAD regimen is a more effective and less toxic salvage regimen for relapsed acute lymphocytic leukemia than high-dose Ara-C-based regimens.

Clinical and laboratory studies of 2-chlorodeoxyadenosine +/- cytosine arabinoside for relapsed or refractory acute myelogenous leukemia in adults

Previous studies in pediatric patients with acute myelogenous leukemia (AML) have suggested that 2-chlorodeoxyadenosine (2CdA) is an effective therapeutic agent. Santana et al (J Clin Oncol 1992; 10: 364-370) reported a CR rate of 8/17 (95% Cl 23-72%) in children with relapsed AML and a median first CR of 21 months. The activity of 2CdA in adults with relapsed or refractory leukemia was therefore investigated in a phase I study. In the phase II study, based on biochemical modulation rationale, 2CdA was combined with Ara-C for adults with relapsed AML to test the effectiveness of this combination therapy. In the phase I study 27 patients (25 AML and two MDS) with a median first CR duration of 21 weeks, received 2CdA at doses ranging from 5 to 13 mg/m2/day by continuous infusion (CI) for 7 days. In vitro and ex vivo pharmacologic studies performed to determine the effect of pretreatment with 2CdA on Ara-CTP accumulation in leukemic blasts demonstrated a 50-65% increase in the rate of Ara-CTP accumulation. Based on this biochemical modulation, 2CdA (12 mg/m2/day x 5 days by CI) was combined with Ara-C (1 g/m2/day over 2 h) in a phase II study. Seventeen patients (15 AML, two MDS) with relapsed AML (median 1st CR of 19 weeks) were treated. In the phase I study two patients died before the day 14 marrow (ED). Marrow hypoplasia developed in 16 of the remaining 25. Leukemic regrowth occurred in nine after a median hypoplastic period of 2 weeks (range 1-3 weeks). The other seven patients died with aplastic marrows, median duration of hypoplasia was 2 weeks, range 1-4 weeks. None achieved CR and the median survival was 10.5 weeks. Toxicity generally was mild except for three late occurring cases of grade III or IV renal dysfunction and two cases of tumor lysis syndrome. The MTD was 10.8 mg/m2/day x 7 days. In the phase II study two patients, both with AML, achieved CR (95% CI 1-33%). In both cases leukemia relapsed after 10 weeks and 17 weeks. There was one ED. Most (11/16) cleared their marrow although leukemic infiltrate regrew in six cases. Toxicity was generally mild, with two episodes of grade 2 GI bleeding, one episode of severe renal dysfunction and one case of grade 2 CNS toxicity. We conclude that as a single agent 2CdA at the MTD is a cytoreductive agent but is not sufficient to achieve CR in adults with relapsed AML. While combination of Ara-C with 2CdA increases the Ara-CTP uptake in these heavily treated patients this regimen does not appear to be an improvement over existing modalities.

Molecular and biologic characterization of a newly established Philadelphia-positive acute lymphoblastic leukemia cell line (Z-33) with an autocrine response to GM-CSF

We have recently established a new Philadelphia chromosome (Ph1)-positive acute lymphoblastic leukemia (ALL) cell line, designated Z-33. This line has L2 morphology, ultrastructural characteristics of lymphoblasts and typical B lineage surface markers identical to those observed in the Ph1-positive ALL patient from whom the line was derived. In addition, a rearranged immunoglobulin heavy-chain gene (JH) band was found in Z-33 cells by Southern blot analysis, confirming B cell clonality. Cytogenetic analysis of the cell line revealed t(9;22)(q34;q11.2). Polymerase chain reaction (PCR)-amplified cDNA from Z-33 cells demonstrated an e1-az BCR-ABL junction, and the p190BCR-ABL protein was detected in them by the immune complex kinase assay. Z-33 cells produce interleukin (IL)-1 beta, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta, Neither IL-1 beta, G-CSF, TNF-alpha, nor their corresponding antibodies affected the cell line's growth. In contrast, anti-GM-CSF neutralizing antibodies suppressed Z-33 colony formation, and GM-CSF stimulated it in a dose-dependent fashion. In addition, receptor studies with biotinylated GM-CSF demonstrated specific binding to Z-33 cells, indicating that the cells express GM-CSF receptors. Taken together, our data suggest that the Ph1-positive Z-33 ALL cells produce GM-CSF, express GM-CSF receptors, and show an autocrine proliferative response to this cytokine.

Quantitation of the nucleophosmin/B23-translocation using imaging analysis

We have previously detected by immunofluorescent assay that the cellular localization of nucleophosmin/B23 (NPM) shifts from the nucleolus to the nucleoplasm (NPM-translocation) after exposure of cells to multiple agents. In order to improve the quantification of the NPM-translocation, we have developed a digital imaging technique. Human Lo leukemia cells, MCF-7 breast carcinoma cells, and fresh human leukemia cells were exposed to anthracyclines or actinomycin D for 4 h. The degree of NPM-translocation was determined and presented as the localization index (LI). Control cells had a LI of about 10, which indicates that the majority of NPM was localized in nucleoli. The LI for drug-treated cells decreased in a dosage- and time-dependent manner. The effect of two classes of anthracycline (daunomycin and aclacinomycin A) and different types of intercalators (daunomycin and actinomycin D) had additive effects on induction of NPM-translocation. The imaging procedure was easily applied to fresh leukemia cells, thus providing useful information regarding drug effects on cancer cells.

A phase I trial of weekly lomustine in patients with advanced cancer

BACKGROUND

Lomustine is a commercially available chloroethyl nitrosourea compound whose antitumor activity in vitro and in animal tumor models exceeds its activity in humans. Part of the poor clinical performance of this drug may be explained by dose-limiting subjective toxicity observed with the standard schedule of one oral dose of approximately 130 mg/m2 every 6-8 weeks.

METHODS

Twenty patients were enrolled in a Phase I clinical trial of weekly oral lomustine. The first dose level was 24 mg/m2, with subsequent dose increases in increments of 6 mg/m2. Intrapatient dose escalations were allowed if there were no toxic reactions noted after 12 weekly doses.

RESULTS

The dose-limiting toxic effect was the development of thrombocytopenia in 35% of patients (6 of 17) treated at 30 mg/m2 after a median of 12 weekly doses (range, 5-20 weeks), whereas in 18% of patients (3 of 17), neutropenia developed after a median of 12 weeks (range, 9-22 weeks). Grade 3 or Grade 4 hematologic toxicity developed in three of three patients whose doses were escalated to 36 mg/m2/week after showing no evidence of toxicity for 12-16 weeks at 30 mg/m2/week. Partial remission was observed in two patients with malignant melanoma, and stable disease was observed in two patients with hypernephroma. Nausea, vomiting, and malaise were not significant complications of treatment.

CONCLUSION

Lomustine can be administered at a dose of 30 mg/m2/week for 12+ weeks to patients with cancer who have received previous treatment with minimal toxicity while retaining antitumor activity.

Determination of plicamycin in plasma by radioimmunoassay

This article describes a method for the determination of plicamycin in plasma by radioimmunoassay. The anti-plicamycin antibody was produced against a plicamycin-bovine serum albumin conjugate prepared by using diazotized p-aminobenzoic acid as a cross-linker. The radiolabeled ligand, 125I-plicamycin, was prepared by the chloramine-T method. The linear plicamycin concentration range was 7-400 ng/ml. The coefficients of variation for intra- and interday variabilities were 7.5 and 15%, respectively. No interference was observed from either the structurally related chromomycin A or concomitantly used drugs hydroxyurea or allopurinol. With this method of testing, plicamycin levels in plasma could be determined in patients receiving small (0.85-1.0 mg/m2) therapeutic plicamycin doses. Preliminary pharmacokinetic data in humans indicate that the plasma drug disappearance curve was biphasic with a mean elimination half-life of 10.6 +/- 1.7 h, total clearance rate of 11.1 +/- 0.4 ml/min/m2, and area under the plasma drug concentration-time curve of 1,289-1,546 ng-h/ml. This assay method is clinically useful for pharmacokinetic studies of plicamycin and may be helpful in the design of rational therapeutic drug trials.

Treatment of newly diagnosed acute myelogenous leukemia with granulocyte-macrophage colony-stimulating factor (GM-CSF) before and during continuous-infusion high-dose ara-C + daunorubicin: comparison to patients treated without GM-CSF

We gave 56 patients with newly diagnosed acute myelogenous leukemia (AML) granulocyte-macrophage colony-stimulating factor (GM-CSF) 20 or 125 micrograms/m2 once daily subcutaneously before (for up to 8 days or until GM-CSF-related complications developed) and during, or only during (patients presenting with blast counts greater than 50,000 or other leukemia-related complications) ara-C (1.5 g/m2 daily x 4 by continuous infusion) and daunorubicin (45 mg/m2 daily x 3) chemotherapy. Because results seemed independent of GM-CSF schedule, we compared results in these 56 patients with results in 176 patients with newly diagnosed AML given the same dose and schedule of ara-C without GM-CSF (110 patients ara-C alone, 66 patients ara-C + amsacrine or mitoxantrone). Comparison involved fitting a logistic regression model predicting probability of complete remission (CR) and a Cox regression model to predict survival (most patients in all three studies were dead) with treatment included as a covariate in both analyses. After adjusting for other prognostically significant covariates [presence of an antecedent hematologic disorder, an Inv (16), t(8;21), or abnormalities of chromosomes 5 and/or 7, performance status, age, bilirubin], treatment with ara-C + daunorubicin + GM-CSF was predictive of both a lower CR rate and a lower survival probability. There were no treatment-covariate interactions, suggesting that the negative effect of this GM-CSF treatment regime was not an artifact of some imbalance in patient characteristics. The unadjusted Kaplan-Meier hazard rate of the ara-C + daunorubicin + GM-CSF group was not uniquely high during the initial 4 weeks after start of therapy, but was highest among the three treatment groups throughout weeks 5 to 16, suggesting that the negative effect of this treatment was not caused by acute toxicity. Patients who did not enter CR with this treatment tended to have persistent leukemia rather than prolonged marrow aplasia, suggesting that this treatment and, in particular, GM-CSF may increase resistance of myeloid leukemia cells to chemotherapy. To date, relapse rates are similar in all three groups (P = .43) (as are survival rates once patients are in CR) but much of the remission duration data is heavily censored, unlike the survival data. Our results suggest caution in the use of GM-CSF to sensitize myeloid leukemia cells to daunorubicin + ara-C chemotherapy.

Mithramycin inhibits SP1 binding and selectively inhibits transcriptional activity of the dihydrofolate reductase gene in vitro and in vivo

The promoter of the human dihydrofolate reductase (DHFR) gene contains two consensus binding sites for the DNA binding protein Sp1. DNAse protection and gel mobility shift assays demonstrate binding of recombinant Sp1 to both decanucleotide Sp1 binding sequences which are located 49 and 14 base pairs upstream of the transcription start site. The more distal of the two binding sites exhibits a somewhat higher affinity for Sp1. The G-C specific DNA binding drug, mithramycin, binds to both consensus sequences and prevents subsequent Sp1 binding. Promoter-dependent in vitro transcription of a DHFR template is selectively inhibited by mithramycin when compared to the human H2b histone gene. A similar effect is also noted in vivo. Mithramycin treatment of MCF-7 human breast carcinoma cells containing an amplified DHFR gene induces selective inhibition of DHFR transcription initiation, resulting in a decline in DHFR mRNA level and enzyme activity. This selective inhibition of DHFR expression suggests that it is possible to modulate the overexpression of the DHFR gene in methotrexate resistant cells.

Fludarabine therapy in macroglobulinemic lymphoma

Fludarabine, a fluorinated analogue of adenine, was given to 11 patients with macroglobulinemic lymphoma, all but one having failed prior standard chemotherapy. Five patients (45%) responded with more than a 50% reduction of immunoglobulin M (IgM) tumor mass for a projected median duration of longer than 1 year. The onset of remission was usually slow, with a median tumor halving time of 5.2 months in responding patients, emphasizing the importance of repeated courses of treatment. Fludarabine is an important new agent effective against macroglobulinemic lymphoma, and should be evaluated further in combination with other active modalities.

Stimulation of myelopoiesis in chronic lymphocytic leukemia and in other lymphoproliferative disorders by recombinant human granulocyte-macrophage colony-stimulating factor

In an attempt to stimulate granulopoiesis, we administered recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) to 11 patients with lymphoproliferative disorders. Ten patients had neutropenia, six of whom had severe neutropenia (less than 500 neutrophils), including two with agranulocytosis. GM-CSF (60-250 micrograms/m2/day) was administered by continuous intravenous infusion daily for 14 days at 2-week intervals. Significant increases in white blood cell counts (1.3-to 11.7-fold) and neutrophils (1.7- to more than 29-fold) were seen in 10 of 11 patients, including one patient with agranulocytosis. Eosinophils (3.9- to greater than 65-fold) and monocytes (1.3- to 5-fold) increased as well. In contrast, no significant increases were seen in total lymphocytes or in different phenotypic subsets of lymphocytes during treatment. The overall proportion of myeloid and lymphoid elements in bone marrow remained stable. These results indicate that GM-CSF is effective in stimulating myelopoiesis in neutropenic states associated with lymphoproliferative disorders. Further studies will be necessary to determine whether the correction of neutropenia ultimately translates into clinical benefit.

Chemotherapy-induced acral erythema: desquamating lesions involving the hands and feet

Patients receiving very high doses of chemotherapeutic drugs, particularly cytarabine (cytosine arabinoside, ara-C, Cytosar), may develop chemotherapy-induced acral erythema, a painful toxic rash of the palmar surfaces of the hands that progresses to edema, blister formation, and desquamation. In more severe cases, the feet are involved, and they show similar changes. Plastic surgeons may be consulted because of the hand involvement and the clinical resemblance, after desquamation, to a very superficial second-degree burn. In patients who have had bone marrow transplantation, this diagnosis must be distinguished from graft-versus-host reaction--a desquamating skin lesion that can affect a similar anatomical area but that is progressive and productive of serious consequences. Acral erythema appears to be self-limited and requires only supportive treatment.

Relapse of adult acute myelogenous leukemia isolated in testicle

Isolated testicular relapse of acute leukemia, although common in children, is rare in adults. A 63-year-old man who had completed induction and intensification chemotherapy presented with unilateral testicular enlargement as the sole manifestation of biopsy-proven acute leukemia relapse. The infiltrative characteristics of acute monocytic leukemia and the anatomic barriers and location of the testicles may have provided a sanctuary from chemotherapy.

Mithramycin blocks protein binding and function of the SV40 early promoter

Specific interactions between DNA and transcription factors are necessary for transcription initiation. These interactions provide a potential target for the selective inhibition of eukaryotic gene expression. Mithramycin is a DNA binding antibiotic which, in the presence of Mg2+, binds G-C containing sequences in the minor groove. The SV40 early promoter contains six G-C decanucleotide sequences, which are binding sites for the transcriptional activating factor, Sp1. Each of the six Sp1 binding sites of this promoter is protected from DNAse 1 digestion by mithramycin binding. Mithramycin binding to the G-C rich sequences in the SV40 early promoter prevents subsequent protein binding to these sequences. The gel retardation of the SV40 early promoter fragment incubated with a HeLa cell extract is completely abrogated by pretreatment of the DNA fragment with mithramycin. The functional significance of mithramycin binding is reflected in the ability of mithramycin to block promoter function. Mithramycin inhibits promoter dependent transcription in an in vitro runoff transcription system in a concentration dependent manner. This suggests that mithramycin prevents transcriptional activation of the SV40 early promoter by blocking binding of transcriptional activating proteins to G-C rich promoter regions.

Phase II study of low-dose continuous infusion homoharringtonine in refractory acute myelogenous leukemia

Thirty-one patients with a diagnosis of refractory acute myelogenous leukemia received homoharringtonine as their first (15 patients) or second (16 patients) salvage therapy. Homoharringtonine was given as a continuous infusion of 2.5 mg/m2 daily for 15 to 21 days to 13 patients (schedule 1), and of 3.0 mg/m2 daily for 15 days in 18 patients (schedule 2). Overall, one patient achieved complete remission (3%), and three (10%) had a hematologic improvement with normalization of the marrow and peripheral blood picture except for persistent thrombocytopenia. Six patients (19%) demonstrated prolonged myelosuppression, three (23%) on schedule 1 and three (17%) on schedule 2. Cardiovascular complications were minimal consisting of hypotension in one patient (3%) and supraventricular arrhythmias in two patients (6%). Hyperglycemia was observed in 42% of patients and was significant in 10%. The authors conclude that homoharringtonine, at the dose schedule investigated, has definite but low antileukemic efficacy. The low-dose continuous infusion schedule was associated with prolonged myelosuppression but no serious cardiovascular complications. The role of such therapy in myeloproliferative disorders, especially chronic myelogenous leukemia, deserves consideration.

Mithramycin selectively inhibits transcription of G-C containing DNA

Mithramycin induces a reversible inhibition of cellular RNA synthesis without affecting DNA synthesis. The authors have shown this drug induces myeloid differentiation of HL-60 promyelocytic leukemia cells and is an effective agent in certain patients with chronic granulocytic leukemia. In order to investigate the mechanism by which this drug inhibits RNA synthesis we have compared the effect of mithramycin on RNA synthesis by whole cells, isolated nuclei, and RNA synthesis by isolated E. coli RNA polymerase and eukaryotic RNA polymerase II. Exposure of HL-60 cells to mithramycin at concentrations of 4.6 X 10(-7) m or higher for 48 hours causes an almost immediate inhibition of RNA synthesis (up to 85% at 4 hours) with only modest cytotoxicity at these concentrations. Endogenous RNA synthesis by isolated nuclei can be inhibited by mithramycin only at high concentrations (greater than 10(-5) m), suggesting that mithramycin primarily may inhibit initiation, rather than elongation. Mithramycin inhibits in vitro transcription of salmon sperm DNA by E. coli RNA polymerase at DNA:drug ratios similar to those required for RNA synthesis inhibition in whole cells. Similar DNA binding studies with synthetic oligonucleotides demonstrate that mithramycin is a potent inhibitor of transcription of Poly dG.dC by E. coli RNA polymerase but has no effect on transcription of Poly dA.dT. The rapid inhibition of whole cell and isolated RNA polymerase transcription, and the relative insensitivity of isolated nuclei, suggest mithramycin may interact with specific DNA sequences in order to inhibit the initiation of RNA synthesis in intact cells.

Bordetella bronchiseptica pneumonia in a patient with chronic lymphocytic leukemia

This case report describes two episodes of pneumonia caused by Bordetella bronchiseptica in a patient with chronic lymphocytic leukemia. There was discrepancy between the in vitro sensitivity testing of the organism and subsequent clinical response to several antimicrobial agents. Human infection with B bronchiseptica is almost always associated with severe underlying disease and contact with an appropriate animal reservoir.

Molecular analysis of chromosome 22 breakpoints in adult Philadelphia-positive acute lymphoblastic leukaemia

The Philadelphia (Ph) translocation, t(9:22)(q 34:q11), is found in the majority of patients with chronic myelogenous leukaemia (CML) as well as in approximately 20% of adult acute lymphoblastic leukaemia (ALL) patients. The chromosome 22 breakpoint in CML has been localized within a restricted 5.8 kb segment of DNA known as the breakpoint cluster region (bcr). To investigate the chromosome 22 breakpoint in ALL, we analysed five adult Ph-positive ALL patients for bcr rearrangement. Rearrangement was detected within bcr in two patients. However, in one patient the break occurred 5' to the first exon of bcr and in two patients the bcr region was not involved. We conclude that the identical cytogenetic marker, t(9:22), may yield a different genomic configuration in ALL and CML.

Preliminary observations on the therapy of the myeloid blast phase of chronic granulocytic leukemia with plicamycin and hydroxyurea

We observed a dramatic improvement in the peripheral blood counts of a patient in the myeloid blast phase of chronic granulocytic leukemia after plicamycin (mithramycin) therapy of concurrent hypercalcemia. We then treated eight additional patients in the blast phase of chronic granulocytic leukemia with a combination of alternate-day plicamycin and daily hydroxyurea. All six patients with myeloid morphology at the time of blast crisis responded with a return to a chronic phase without an intervening pancytopenic period. Of three patients with lymphoid morphology at the time of treatment, only one responded (this patient had recently relapsed and converted from myeloid to lymphoid morphology). Another patient with nonmyeloid, nonlymphoid blast morphology also did not respond. Continual therapy with the two-drug combination appeared to be necessary, since early relapses were seen in responding patients whose therapy was interrupted. These data are preliminary and will need further confirmation, but they suggest that the combination of alternate-day plicamycin and daily hydroxyurea may be effective in the myeloid blast phase of chronic granulocytic leukemia.

Response to 2'-deoxycoformycin after failure of interferon-alpha in nonsplenectomized patients with hairy cell leukemia

Two patients with hairy cell leukemia with massive splenomegaly and severe pancytopenia were treated with recombinant alpha-A interferon (IFN-alpha-2a). There was no significant response to a trial of IFN-alpha-2a (11 and 20 weeks) with respect to blood counts or spleen size. Subsequent treatment with 2'-deoxycoformycin (dCF) for 8 consecutive weeks (4 mg/m2/wk) resulted in normalization of spleen size and a normalization of peripheral blood counts and bone marrow in one patient. The second patient demonstrated a reduction in spleen size and improved blood counts following 9 weeks of dCF therapy but eventually became refractory. This demonstrates that dCF is non-cross-resistant with interferon and confirms the efficacy of dCF in nonsplenectomized patients.

In vivo differentiation of blast-phase chronic granulocytic leukemia. Expression of c-myc and c-abl protooncogenes

A patient with chronic granulocytic leukemia in acute blastic transformation was treated with mithramycin, an RNA synthesis inhibitor, after in vitro exposure of her leukemic cells to mithramycin showed differentiation to normal appearing granulocytes. Mithramycin therapy in vivo resulted in a prompt and dramatic hematologic response. Before therapy, the patient's leukemic cells had high levels of transcription of the cellular myc and abl protooncogenes. After initiation of therapy, protooncogene mRNA decreased rapidly. These observations indicate that mithramycin can induce differentiation both in vitro and in vivo and suggest that such changes may be associated with altered oncogene expression.

Deoxyribonucleoside triphosphate accumulation by leukemic cells

The toxicity of the deoxyribonucleosides, 2'-deoxyadenosine, 2'-deoxyguanosine, and thymidine, for human T lymphoblasts is mediated by the accumulation of the corresponding deoxyribonucleoside triphosphate (dATP, dGTP, or dTTP, respectively). We have examined whether leukemic cells of non-T-cell origin are capable of accumulating deoxyribonucleotides in culture and whether this capability correlates with the activities of purine metabolizing enzymes in these cells. We have found that non-T, non-B acute lymphoblastic leukemia cells with low ecto-5'-nucleotidase and high adenosine deaminase activities increase their dATP pools by greater than tenfold when exposed to deoxyadenosine and an inhibitor of adenosine deaminase in culture. Cells from 2 of 9 patients with chronic lymphocytic leukemia and 4 of 11 patients with acute nonlymphoblastic leukemia achieved similar elevations in dATP, but there was no relationship between dATP accumulation and adenosine deaminase, purine nucleoside phosphorylase, or ecto-5'-nucleotidase activities. Treatment of four individuals with acute lymphoblastic leukemia with the adenosine deaminase inhibitor, 2'-deoxycoformycin, resulted in elevations in plasma deoxyadenosine concentrations and in increments in lymphoblast dATP levels that were similar to those measured in lymphoblasts cultured with deoxyadenosine and deoxycoformycin prior to treatment. In vitro incubations of leukemic cells with deoxyribonucleosides may provide a rational basis for the use of these compounds as chemotherapeutic agents.

Adenosine deaminase deficiency with normal immune function. An acidic enzyme mutation

In most instances, marked deficiency of the purine catabolic enzyme adenosine deaminase results in lymphopenia and severe combined immunodeficiency disease. Over a 2-yr period, we studied a white male child with markedly deficient erythrocyte and lymphocyte adenosine deaminase activity and normal immune function. We have documented that (a) adenosine deaminase activity and immunoreactive protein are undetectable in erythrocytes, 0.9% of normal in lymphocytes, 4% in cultured lymphoblasts, and 14% in skin fibroblasts; (b) plasma adenosine and deoxyadenosine levels are undetectable and deoxy ATP levels are only slightly elevated in lymphocytes and in erythrocytes; (c) no defect in deoxyadenosine metabolism is present in the proband's cultured lymphoblasts; (d) lymphoblast adenosine deaminase has normal enzyme kinetics, absolute specific activity, S20,w, pH optimum, and heat stability; and (e) the proband's adenosine deaminase exhibits a normal apparent subunit molecular weight but an abnormal isoelectric pH. In contrast to the three other adenosine deaminase-deficient healthy subjects who have been described, the proband is unique in demonstrating an acidic, heat-stable protein mutation of the enzyme that is associated with less than 1% lymphocyte adenosine deaminase activity. Residual adenosine deaminase activity in tissues other than lymphocytes may suffice to metabolize the otherwise lymphotoxic enzyme substrate(s) and account for the preservation of normal immune function.

S-adenosylhomocysteine catabolism and basis for acquired resistance during treatment of T-cell acute lymphoblastic leukemia with 2'-deoxycoformycin alone and in combination with 9-beta-D-arabinofuranosyladenine

A patient with refractory T-cell acute lymphoblastic leukemia was treated with eight courses of the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF), over a 5-month period. After developing resistance to dCF, he responded to treatment with the combination of dCF and 9-beta-D-arabinofuranosyladenine (ara-A). We monitored the levels in plasma and urine of adenosine, 2'-deoxyadenosine, and ara-A as well as the accumulation of their nucleotide derivatives in erythrocytes and circulating lymphoblasts. We also monitored the activities of adenosine deaminase and S-adenosylhomocysteine (AdoHcy) hydrolase and the concentrations of AdoHcy and S-adenosylmethionine in lymphoblasts. Production of 2'-deoxyadenosine was related to both the duration of dCF infusion and the magnitude of cytolysis that occurred during treatment: much more 2'-deoxyadenosine was produced by dCF infusion when disease was active than by the same infusion given during remission. Resistance to dCF was associated with a decrease of greater than 90% in the amount of deoxyadenosine 5'-triphosphate accumulated by circulating lymphoblasts. Infusion of dCF resulted in increases of up to 20-fold in the concentration of AdoHcy in circulating lymphoblasts, causing a decrease in the S-adenosylmethionine:AdoHcy ratio (the "methylation index") from a pretreatment value of greater than 40:1 to less than 4:1. This ratio decreased to 2.5:1 during combined treatment with dCF and ara-A, which caused nearly complete inactivation of lymphoblast AdoHcy hydrolase. Decline in the methylation index was accompanied by inhibition of the methylation of newly synthesized lymphoblast RNA. Impaired ability to catabolize AdoHcy may have contributed to the cytolytic responses to dCF and ara-A, as well as to hepatic and central nervous system toxicity associated with their combined use.

Phase I evaluation of semustine in a weekly schedule

A phase I study of weekly semustine was conducted in 32 patients with advanced cancer. Doses were escalated from 18 to 36 mg/m2/week. At a dose of 36 mg/m2/week, 43% of the patients developed platelet counts less than 100,000/mm3 after a median of 20 weeks on study, and 25% developed wbc counts less than 3000/mm3 after a median of 16 weeks on study. Drug-related nausea was reported by only one patient and was the only subjective toxic effect reported. Tumor regressions were noted in patients with adenocarcinoma of the colon, melanoma, and mixed adenocarcinoma and squamous cell lung cancer. A reasonable starting dose for phase II studies is 36 mg/m2/week, with dose adjustments based on platelet and wbc counts.

Alterations in erythrocyte adenine nucleotide pools resulting from 2'-deoxycoformycin therapy

2'-Deoxycoformycin, a tight-binding adenosine deaminase inhibitor, was administered to 11 adult patients with refractory lymphoproliferative diseases. Total doses ranged from 1.0 to 13.5 mg/kg. Inhibition of lymphoblast adenosine deaminase was obtained in all cases and tumor cytoreduction was noted in eight of ten cases, but no clinically meaningful remissions were obtained. Major toxicities occurred in five patients and included pulmonary edema, renal failure, central nervous system toxicity, hypotension, and death. Toxicity prevented retreatment in several cases in which marked cytoreduction occurred. Deoxyadenosine triphosphate accumulated to a variable extent in the red blood cells of all patients, and a reciprocal decrease in erythrocyte adenosine triphosphate was noted in all cases but one. All patients who suffered major organ toxicity had red blood cell deoxyadenosine triphosphate/adenosine triphosphate ratios greater than 1.3. These data suggest that the degree of replacement of adenosine triphosphate by deoxyadenosine triphosphate in erythrocytes reflects the biochemical milieu which may result in systemic toxicity following treatment with 2'-deoxycoformycin.

Monocyte-mediated antibody-dependent cell-mediated cytotoxicity: the role of the metabolic burst

Human monocytes respond to opsonized microorganisms with a "metabolic burst" composed of an increase in oxygen consumption, an increase in hexose monophosphate shunt (HMPS) activity, and the generation of reactive oxygen species (ROS). We investigated the role of the metabolic burst in antibody-dependent cell-mediated cytotoxicity (ADCC) by human monocytes toward anti-D coated erythrocyte target cells because recent studies suggested a role for oxygen-dependent bactericidal mechanisms in ADCC. In normal monocytes, we found that ADCC was nearly halved under hypoxic conditions. Several agents known to impair activation of the burst, such as vincristine, cation chelators, and a sulfhydryl reagent, all decreased cytotoxicity if added before initiation of contact between target and effector cells. Cytotoxicity was inhibited by 2-deoxyglucose but not fluoride, suggesting a nonglycolytic role for glucose in ADCC, perhaps in the HMPS pathway. Although these data suggested a role for the metabolic burst in ADCC, scavengers of ROS did not impair cytotoxicity, and monocytes from chronic granulomatous disease (CGD) patients who had a defective metabolic burst had normal levels of ADCC. We conclude that ADCC toward anti-D coated erythrocyte target cells was the result of at least two independent but closely related cytotoxic pathways. Although one of these pathways appeared to involve the metabolic burst, the potentially cytotoxic reactive oxygen species did not appear to play a role in this system.

ATP depletion as a consequence of adenosine deaminase inhibition in man

Hereditary deficiency of the enzyme adenosie deaminase (adenosine aminohydrolase, EC 3.5.4.4) results in an immunodeficiency syndrome characterized by a marked reduction in circulating lymphocytes. We have administered 2'-deoxycoformycin, a potent inhibitor of adenosine deaminase, to a patient with a lymphoproliferative malignancy. The clinical consequences of pharmacologic inhibition of adenosine deaminase activity included an abrupt decrease in the lymphocyte count, abnormalities of renal and hepatic function, and hemolytic anemia. The plasma concentrations of adenosine and deoxyadenosine rose to peak values of 13 microM and 5 microM, respectively, and erythrocyte dATP levels increased to 110 pmol/10(6) cells over 9 days. There was a corresponding decrease in erythrocyte ATP levels from 128 to < 6 pmol/10(6) cells. A similar profound reductin in ATP occurred in the erythrocytes of a second patient. The rapid and unexpected depletion of ATP associated with dATP accumulation may account, at least in part, for the toxicity associated with 2'-deoxycoformycin administration. The inverse relationship of ATP and dATP raises major questions about the control of energy metabolism in erythrocytes.

Inhibition of adenosine deaminase activity results in cytotoxicity to T lymphoblasts in vivo

We have treated a patient with refractory T-cell acute lymphoblastic leukemia with 2'-deoxycoformycin, a potent inhibitor of the enzyme adenosine deaminase. Inhibition of adenosine deaminase activity resulted in (1) an abrupt rise in plasma deoxyadenosine, but not adenosine, concentrations; (2) accumulation of deoxyadenosine triphosphate by lymphoblasts; (3) inhibition of the enzyme S-adenoylhomocysteine hydrolase; and (4) rapid lysis of the leukemic cells. The patient died suddenly 3 days after therapy was discontinued, and postmortem examination revealed a complete absence of leukemic cells in all organs. Pharmacologic inhibition of adenosine deaminase activity can result in the lysis of T lymphoblasts in vivo, and this effect appears to be mediated by deoxyadenosine.

Immune thrombocytopenic purpura

ITP is a hemorrhagic disorder in which thrombocytopenia is associated with increased peripheral destruction of platelets. It is a syndrome of different diseases, all of which have in common shortened platelet survival owing to the presence of an antiplatelet antibody. Most cases are secondary to an identifiable etiologic agent.

Quinine protects pyruvate-kinase deficient red cells from dehydration

Pyruvate kinase deficient red blood cells have an abnormal tendency to lose ATP when exposed to low pO2 or cyanide, whereas normal red cells do not. Once energy is depleted, all red cells take up calcium and subsequently lose intracellular potassium and water. It has been shown previously that quinine will inhibit the potassium and water flux seen in energy depleted normal cells. The present study indicates that quinine protects cyanide treated pyruvate kinase deficient erythrocytes from water and potassium loss. Quinine does not prevent ATP depletion or calcium uptake. By six hours, cyanide treated pyruvate kinase deficient cells have lost an average of 486 gm of water per kilogram cell solids and 140 mmoles of potassium per kilogram of cell solids, while cells treated with both quinine and cyanide have lost only 106 gm of water per kilogram of cell solids and 77 mmoles of potassium per kilogram of cell solids. These data support the concept that the membrane lesion in pyruvate kinase deficiency is secondary to ATP depletion and is a manifestation of the Gardos effect. Quinine may have therapeutic potential in the treatment of pyruvate kinase deficiency hemolytic anemia.