Molecular alterations of the IDH1 gene in AML: a Children's Oncology Group and Southwest Oncology Group study

Recent whole-genome sequencing efforts led to the identification of IDH1^R132 mutations in AML patients. We studied the prevalence and clinical implications of IDH1 genomic alterations in pediatric and adult AML. Diagnostic DNA from 531 AML patients treated on Children’s Oncology Group trial COG-AAML03P1 (N=257), and Southwest Oncology Group trials SWOG-9031, SWOG-9333, and SWOG-9500 (N=274), were tested for IDH1 mutations. Codon R132 mutations were absent in the pediatric cohort, but were found in 12/274 adult patients (4.4%, 95% CI 2.3-7.5%). IDH1^R132 mutations occurred most commonly in patients with normal karyotype, and those with FLT3/ITD and NPMc mutations. Patients with IDH1^R132 mutations trended towards higher median diagnostic WBC counts (59.2 × 10⁹/L vs. 29.1 × 10⁹/L, P=0.19) than those without mutations, but the two groups did not differ significantly in age, bone marrow blast percentage, overall survival, or relapse-free survival. Eleven patients (2.1%) harbored a novel V71I sequence alteration, which was found to be a germline polymorphism. IDH1 mutations were not detected in pediatric AML, and are uncommon in adult AML.

Efficacy of high-dose therapy and autologous hematopoietic stem cell transplantation for non-Hodgkin's lymphoma in adults 60 years of age and older

High-dose therapy (HDT) with autologous stem cell transplantation (ASCT) is the optimal treatment for patients with relapsed aggressive non-Hodgkin's lymphoma (NHL). HDT, however, is often reserved for relatively younger patients due to limited data in older adults. We treated 53 patients aged 60 years and older (median age 62 years, range 60.3-67.7 years) with HDT and ASCT for NHL at our centers. Forty-four patients (83%) had aggressive histology, 75% had chemosensitive disease and all had failed anthracycline therapy. Conditioning regimens included busulfan, melphalan, and thiotepa (45%); cyclophosphamide (CY), etoposide (VP-16), and total body irradiation (TBI) (30%); CY and TBI (15%); and other regimens (10%). Estimated 4-year overall survival (OS), progression-free survival, and treatment-related mortality (TRM) were 33%, 24% and 22%, respectively. A multivariable analysis demonstrated that patients with chemosensitive disease (P = 0.03) and < or =3 prior regimens (P = 0.03) had superior survival. Four-year OS in patients with chemosensitive disease was 39% vs 15% in patients with chemoresistant disease. Reduced TRM was associated with the CY, VP-16 and TBI regimen (P = 0.02). HDT therapy with ASCT may result in prolonged survival and potential cure for about a quarter of elderly patients, and for almost 40% with chemosensitive disease. Optimal conditioning regimen selection may further improve outcome by reducing TRM. Age alone should not be used to exclude patients from receiving myeloablative therapy with ASCT.

Comparison of the L10M consolidation regimen to an alternative regimen including escalating methotrexate/L-asparaginase for adult acute lymphoblastic leukemia: a Southwest Oncology Group Study

The effectiveness of intensive post-remission chemotherapy regimens for adult patients with acute lymphoblastic leukemia (ALL) is limited by both a high rate of disease recurrence and a substantial incidence of treatment toxicity. To evaluate a potentially more effective and less toxic approach, we conducted a multicenter phase III trial of consolidation therapies comparing the standard L10M regimen with one combining the brief, intensive L17M regimen and escalating methotrexate (MTX) and L-asparaginase (L-asp). Patients over age 15 with previously untreated ALL were eligible. Induction therapy included vincristine, prednisone, doxorubicin, cyclophosphamide and intrathecal methotrexate administered over 36 days. Patients who achieved complete remission (CR) were randomized to receive consolidation with either the L10M regimen or with DAT (daunomycin, cytosine arabinoside, 6-thioguanine) and escalating MTX and L-asp. The randomization was stratified by age, WBC and Ph chromosome status. Maintenance therapy was the same in both arms. Of 353 eligible patients, 218 (62%) achieved CR and 195 were randomized. The treatment arms did not differ significantly with respect to disease-free survival (DFS; P= 0.46) or overall survival (P= 0.39). Estimated DFS at 5 years was 32% (95% confidence interval (CI) 23-42%) in the L10M arm and 25% (95% CI 16-33%) in the DAT/MTX/L-asp arm. In each arm, 4% of patients died of toxicities (infection in all but one case). Infections and nausea/vomiting were somewhat more common in the L10M arm (occurring in 68% and 53% of patients respectively) than the DAT/MTX/L-asp arm (56% and 33%). The DAT/MTX/L-asp consolidation regimen was associated with some reduction in nonfatal toxicities, but no significant improvement in DFS, overall survival or non-relapse mortality when compared to the standard L10M regimen.

Lymphoproliferative disorders presenting as mediastinal neoplasms

Lymphoproliferative disorders may present in any organ of the body. The mediastinum is an uncommon location for presentation of these heterogeneous disorders, but involvement of the mediastinum may be the sole site of disease for several aggressive lymphomas. Both Hodgkin's disease and non-Hodgkin's lymphoma may present in the mediastinum. The most common types of non-Hodgkin's lymphoma involving the mediastinum include lymphoblastic lymphoma and mediastinal large cell lymphoma. These lymphomas most commonly develop in the anterior mediastinum but may be seen in the middle and posterior mediastinum. Symptoms associated with a mediastinal presentation of a lymphoproliferative disorder are often attributable to compression of mediastinal structures (eg, superior vena cava syndrome) or invasion of thoracic structures such as the pericardium or pleura. Although staging can be performed with routine imaging studies, surgical intervention is often required to ensure accurate histologic diagnosis of these lymphomas. Once a diagnosis has been established, therapeutic modalities usually include chemotherapy and/or radiotherapy.

A phase I study of induction chemotherapy for older patients with newly diagnosed acute myeloid leukemia (AML) using mitoxantrone, etoposide, and the MDR modulator PSC 833: a southwest oncology group study 9617

Older patients with acute myelogenous leukemia (AML) have overexpression of P-glycoprotein (Pgp+), and this has been shown to correlate quantitatively with therapeutic outcome. Since Pgp-mediated efflux of cytotoxic drugs can be inhibited by the cyclosporine analogue, PSC 833, we investigated the use of this agent with a 5-day mitoxantrone/etoposide regimen in patients over age 55 with newly diagnosed AML. Previous studies suggested a 33% incidence of grade IV/V non-hematologic toxicity with the use of mitoxantrone 10 mg/M(2) and etoposide 100 mg/M(2), each for 5 days, in this patient population. Since PSC 833 alters the pharmacokinetic excretion of MDR-related cytotoxins, this phase I dose-finding study was performed to identify doses of mitoxantrone/etoposide associated with a similar 33% incidence of grade IV/V non-hematologic toxicity, when given with PSC 833. Mitoxantrone/etoposide (M/E) doses were escalated in fixed ratio from a starting dose of M: 4 mg/M(2) and E: 40 mg/M(2), to M: 7 mg/M(2) and E: 70 mg/M(2), in successive cohorts of eight patients each. PSC 833 was well tolerated and the MTD of this M/E regimen with PSC 833 in this population was M: 6 mg/M(2) and E: 60 mg/M(2). The complete response (CR) rate for all patients was 50% (15/30) and was considerably higher for de novo than for secondary AML. These data suggest that the addition of PSC 833 to an M/E regimen for older patients with untreated AML is well tolerated but requires a reduction in M/E dosing to avoid increased toxicity.

Follow-up of relapsed B-cell lymphoma patients treated with iodine-131-labeled anti-CD20 antibody and autologous stem-cell rescue

PURPOSE

Radioimmunotherapy (RIT) is a promising treatment approach for B-cell lymphomas. This is our first opportunity to report long-term follow-up data and late toxicities in 29 patients treated with myeloablative doses of iodine-131-anti-CD20 antibody (anti-B1) and autologous stem-cell rescue.

PATIENTS AND METHODS

Trace-labeled biodistribution studies first determined the ability to deliver higher absorbed radiation doses to tumor sites than to lung, liver, or kidney at varying amounts of anti-B1 protein (0.35, 1.7, or 7 mg/kg). Twenty-nine patients received therapeutic infusions of single-agent (131)I-anti-B1, given at the protein dose found optimal in the biodistribution study, labeled with amounts of (131)I (280 to 785 mCi [10.4 to 29.0 GBq]) calculated to deliver specific absorbed radiation doses to the normal organs, followed by autologous stem-cell support.

RESULTS

Major responses occurred in 25 patients (86%), with 23 complete responses (CRs; 79%). The nonhematopoietic dose-limiting toxicity was reversible cardiopulmonary insufficiency, which occurred in two patients at RIT doses that delivered > or = 27 Gy to the lungs. With a median follow-up time of 42 months, the estimated overall and progression-free survival rates are 68% and 42%, respectively. Currently, 14 of 29 patients remain in unmaintained remissions that range from 27+ to 87+ months after RIT. Late toxicities have been uncommon except for elevated thyroid-stimulating hormone (TSH) levels found in approximately 60% of the subjects. Two patients developed second malignancies, but none have developed myelodysplasia (MDS).

CONCLUSION

Myeloablative (131)I-anti-B1 RIT is relatively well tolerated when given with autologous stem-cell support and often results in prolonged remission durations with few late toxicities.

Phase I study of a humanized anti-CD11/CD18 monoclonal antibody in multiple sclerosis

OBJECTIVE

To evaluate the safety, pharmacokinetics, pharmacodynamics, and immunogenicity of a humanized anti-CD11/CD18 monoclonal antibody (Hu23F2G) in patients with multiple sclerosis.

METHODS

In this phase I uncontrolled dose escalation study, patients (n = 24) with primary or secondary progressive multiple sclerosis received single intravenous infusions of Hu23F2G (0.01 to 4.0 mg/kg). Study parameters included safety, pharmacology, immunogenicity, and brain magnetic resonance imaging (MRI).

RESULTS

Hu23F2G had few adverse effects, but 2 cases of urinary tract infection and 2 cases of gingivitis did occur. Transient leukocytes developed in some subjects receiving > or = 1.0 mg/kg. The pharmacokinetic response was nonlinear, with the area under the curve increasing out of proportion to the increase in dose. The mean terminal half-life increased with dose and was 21.9 (SD, 12.8) hours at the 4.0 mg/kg dose. High saturation (> 80%) of CD11/CD18 on circulating leukocytes was achieved with doses > or = 0.2 mg/kg. The duration of high leukocyte saturation was dose-dependent, persisting for more than a week at the 4.0 mg/kg dose. A marked decrease in leukocyte migration in response to cutaneous inflammation was observed. Antibodies against Hu23F2G were not detected. The neurologic examinations were stable except for 1 subject who had worsening weakness associated with an infection. No significant changes were noted on brain MRI scans.

CONCLUSIONS

Hu23F2G was tolerated at doses that achieved high degrees of leukocyte CD11/CD118 saturation with in vivo inhibition of leukocyte migration. Because this phase I study was not designed to determine the clinical efficacy of Hu23F2G, further studies are needed.

High dose chemotherapy for the treatment of malignant brain tumors

Conventional treatment of malignant high grade gliomas includes maximal resection followed by external beam radiotherapy. The addition of adjuvant chemotherapy has provided little improvement in the median duration of survival for these patients, particularly those patients with glioblastoma multiforme. The failure of conventional dose chemotherapy to improve the outcome of patients with high grade brain tumors has led several investigators to utilize high dose chemotherapy in order to overcome the limited benefit seen with conventional dose therapy which is due to intrinsic drug resistance as well as the impermeability of blood brain barrier. The majority of published studies utilizing this approach suggest that the addition of high dose chemotherapy with bone marrow transplant is of marginal benefit. However, most of these trials include small numbers of patients with advanced, refractory disease. A few trials have been reported utilizing high dose therapy in an adjuvant setting and the data from these studies are somewhat more promising. This review will analyze these studies and also discuss possible modifications of this approach in order to improve this aggressive treatment for patients who otherwise would have a dismal prognosis.

Micro-scale method for liquid-chromatographic determination of chloramphenicol in serum

We describe the use of "high-performance" liquid chromatography to measure chloramphenicol in as little as 25 microL of serum. Serum is treated to precipitate proteins with acetonitrile containing p-nitroacetanilide as an internal standard. Chloramphenicol is eluted with a mobile phase of methanol in pH 7.0 phosphate buffer (35/65 by vol). The drug is measured at 278 nm and simultaneously monitored at 254 nm; interfering substances are detected by examining the 278 nm/254 absorbance ratios. This method is sensitive to less than 0.5 mg/L and the standard curve is linear to at least 50 mg/L. Inter-day precision ranged between 3--6%. We encountered no interference from endogenous compounds or from other drugs we tested.

Micro-scale method for liquid-chromatographic determination of chloramphenicol in serum

We describe the use of "high-performance" liquid chromatography to measure chloramphenicol in as little as 25 microL of serum. Serum is treated to precipitate proteins with acetonitrile containing p-nitroacetanilide as an internal standard. Chloramphenicol is eluted with a mobile phase of methanol in pH 7.0 phosphate buffer (35/65 by vol). The drug is measured at 278 nm and simultaneously monitored at 254 nm; interfering substances are detected by examining the 278 nm/254 absorbance ratios. This method is sensitive to less than 0.5 mg/L and the standard curve is linear to at least 50 mg/L. Inter-day precision ranged between 3--6%. We encountered no interference from endogenous compounds or from other drugs we tested.