Elitek-rasburicase: an effective means to prevent and treat hyperuricemia associated with tumor lysis syndrome, a Meeting Report, Dallas, Texas, January 2002

Renal precipitation of uric acid associated with tumor lysis syndrome (TLS) is a major complication in the management of leukemia, lymphoma, and other drug-sensitive cancers. Management of hyperuricema has historically consisted of administration of allopurinol, hydration, alkalinization to maintain pH between 7.0 and 7.3, and in some cases diuresis. Allopurinol, a xanthine analogue, blocks xanthine oxidase and formation of uric acid. Urate oxidase converts uric acid to allantoin, which is 5-10 times more soluble than uric acid. Homo sapiens cannot express urate oxidase because of a nonsense mutation. Urate oxidase was initially purified from Aspergillus flavus fungus. Treatment with this nonrecombinant product had been effective in preventing renal precipitation of uric acid in cancer patients, but was associated with a relatively high frequency of allergic reactions. This enzyme was recently cloned from A. flavus and is now manufactured as a recombinant protein. Clinical trials have shown this drug to be more effective than allopurinol for prevention and treatment of hyperuricemia in leukemia and lymphoma patients. This drug has been approved in Europe as well as the US and several clinical trials are in progress to further determine its clinical utility in other patient subsets. The purpose of this meeting was to discuss usefulness of recombinant urate oxidase, also known as rasburicase, Fasturtec, and Elitek, for the management of TLS in certain cancer patients.

Ifosfamide, carboplatin and etoposide in children with poor-risk relapsed Wilms' tumor: a Children's Cancer Group report

BACKGROUND

The outcome of children with relapsed Wilms' tumor is poor, especially with poor-risk factors such as unfavorable histology, early recurrence, previous three-drug therapy, relapse not confined to lungs and abdominal relapse following abdominal radiotherapy. We report the overall response rate, progression-free survival and overall survival of 11 children with relapsed and poor-risk Wilms' tumor following ifosfamide/carboplatin/etoposide (ICE) chemotherapy.

PATIENTS AND METHODS

ICE therapy consisted of ifosfamide 1800 mg/m2/day (on day 0-4), carboplatin 400 mg/m2/day (on day 0-1) and etoposide 100 mg/m2/day (on day 0-4). The median age at diagnosis was 39 months (range from 13 months to 16 years) and the median time to relapse after initial diagnosis was 9 months (range 4-72 months). All but one patient had at least one poor prognostic feature, with eight patients showing three or four.

RESULTS

After ICE chemotherapy the number of patients showing a complete response (CR) was three (27%) and a partial response (PR) was six (55%). The overall response rate (CR+PR) was 82%. Five of the six patients with a PR subsequently achieved a CR with further therapy. The 3-year event-free survival and overall survival were 63.6 +/- 14.5%.

CONCLUSIONS

The response rate in children with relapsed and poor-risk Wilms' tumor is >80% with ICE re-induction chemotherapy followed by post-ICE therapy. The optimal approach for post-ICE consolidation therapy has yet to be determined.

Feasibility study of IL-11 and granulocyte colony-stimulating factor after myelosuppressive chemotherapy to mobilize peripheral blood stem cells from heavily pretreated patients

PURPOSE

Pediatric patients with solid tumors treated with prolonged dose-intensive chemoradiotherapy are poor mobilizers of peripheral blood stem cells (PBSC). We have conducted a pilot study to mobilize PBSC in eight pediatric patients with relapsed solid tumors using ifosfamide, carboplatin, and etoposide (ICE) followed-up by IL-11 plus granulocyte colony-stimulating factor (G-CSF).

PATIENTS AND METHODS

Patients received ifosfamide 1.8 g/m2 per day for 5 days, carboplatin 400 mg/m2 per day for 2 days, and etoposide 100 mg/m2 per day for 5 days. After completion of ICE chemotherapy, patients received daily subcutaneous injections of G-CSF (5 microg/kg per day) and IL-11 (50-100 microg/kg per day) until peripheral stem cell apheresis.

RESULTS

The median age was 11 years. Diagnosis included three relapsed Hodgkin disease, three relapsed central nervous system tumors, one relapsed Wilms tumor, and one relapsed rhabdomyosarcoma. The median number of apheresis procedures required to obtain 5 x 10(6) CD34+ cells/kg was one. The mean +/- standard error of mean (SEM) total CD34+ cells collected was 14.0+/-2.7 x 10(6)/kg. The mean +/- SEM total CD34+/CD41+ cells collected was 4.6+/-1.9 x 10(6)/kg. Seven of the eight patients have subsequently undergone myeloablative chemotherapy with autologous PBSC transplantation and have reconstituted hematopoiesis with a median time to neutrophil recovery of 10 days and platelet recovery of 15.5 days.

CONCLUSIONS

We conclude that the regimen of ICE/IL-11 plus G-CSF is successful in mobilizing large numbers of CD34+ PBSC cells with a limited number (one) of apheresis collections in patients that have previously been heavily pretreated with chemotherapy/radiotherapy.

A randomized comparison between rasburicase and allopurinol in children with lymphoma or leukemia at high risk for tumor lysis

Standard therapy in the United States for malignancy-associated hyperuricemia consists of hydration, alkalinization, and allopurinol. Urate oxidase catalyzes the enzymatic oxidation of uric acid to a 5 times increased urine soluble product, allantoin. Rasburicase is a new recombinant form of urate oxidase available for clinical evaluation. This multicenter randomized trial compared allopurinol to rasburicase in pediatric patients with leukemia or lymphoma at high risk for tumor lysis. Patients received the assigned uric acid-lowering agent for 5 to 7 days during induction chemotherapy. The primary efficacy end point was to compare the area under the serial plasma uric acid concentration curves during the first 96 hours of therapy (AUC(0-96)). Fifty-two patients were randomized at 6 sites. In an intent-to-treat analysis, the mean uric acid AUC(0-96) was 128 +/- 70 mg/dL.hour for the rasburicase group and 329 +/- 129 mg/dL.hour for the allopurinol group (P <.0001). The rasburicase versus allopurinol group experienced a 2.6-fold (95% CI: 2.0-3.4) less exposure to uric acid. Four hours after the first dose, patients randomized to rasburicase compared to allopurinol achieved an 86% versus 12% reduction (P <.0001) of initial plasma uric acid levels. No antirasburicase antibodies were detected at day 14. This randomized study demonstrated more rapid control and lower levels of plasma uric acid in patients at high risk for tumor lysis who received rasburicase compared to allopurinol. For pediatric patients with advanced stage lymphoma or high tumor burden leukemia, rasburicase is a safe and effective alternative to allopurinol during initial chemotherapy.

Successful treatment of relapsed Burkitt's lymphoma using unrelated cord blood transplantation as consolidation therapy

We report a 10-year-old male with widespread recurrent Burkitt's lymphoma who underwent successful mismatched unrelated cord blood transplantation (UCBT) following salvage chemotherapy. He was conditioned with TBI, antithymocyte globulin (ATG) and high-dose VP-16 and achieved full donor engraftment. He experienced grade II skin and grade I gastrointestinal acute GVHD with no chronic GVHD. He is alive with no evidence of disease 24 months following UCBT. Bone Marrow Transplantation (2000) 25, 1311-1313.

The p53 signal transduction pathway is intact in human neuroblastoma despite cytoplasmic localization

Mutations of the p53 tumor suppressor gene are rarely found in neuroblastoma. Though typically a nuclear protein, a number of tumor cell types have recently been reported to exhibit cytoplasmic p53 immunostaining, and it has been suggested that altered cellular localization is another mechanism of inhibiting p53 function. We examined p53 protein expression, localization, and function in neuroblastoma cell lines with wild-type p53 genes. Basal p53 levels were largely confined to the cytoplasmic compartment in these cells. However, after irradiation, p53 protein levels increased predominately in the nucleus. Transcriptional activity of p53 was intact in these cells because "downstream" proteins, p21WAF1 and MDM2, were induced by irradiation. In contrast to a neuroblastoma cell line harboring a mutant p53 gene, the neuroblastoma cells with wild-type protein were associated with an intact G1 arrest after DNA damage. The induced nuclear protein in these neuroblastoma cells also appeared functional as measured by its capacity to bind to a DNA oligomer containing a p53-consensus sequence. We have concluded that although p53 expression in neuroblastoma cells is primarily localized to the cytosol, ionizing radiation induces a functional p53 protein in the nucleus and that this cytoplasmic sequestration of p53 in human neuroblastoma is not a mechanism of inactivating p53 function.

Dysplastic nevus syndrome: a phenotypic association of sporadic cutaneous melanoma

Clinical photographs of 79 prospectively studied cases of non-familial cutaneous malignant melanoma were reviewed; special attention was directed to the distribution pattern of coexistent melanocytic lesions. A group of 15 patients had moles on the covered buttock area. Seven of these patients had large clinically atypical nevi, and biopsies of these nevi showed severe melanocytic dysplasia. Residual elements of melanocytic dysplasia were identified in five of the primary melanomas in this group of patients. It is suggested that these patients represent a distinctive syndrome, the Dysplastic Nevus Syndrome (DNS) and that they are at increased risk for development of primary cutaneous malignant melanoma. The clinically and histologically distinctive dysplastic nevi of these patients are identical to the precursor lesion for melanoma that we have previously described in a familial context, the B-K mole syndrome. This paper represents the first description of this form of dysplasia in non-familial melanoma.

End-point parameter adjustment on a small desk-top programmable calculator for logit-log analysis of radioimmunoassay data

We describe an improved method of logit-log curve fitting, by adjusting end-point parameters in radioimmunoassay studies, for use with a small desk-top programmable calculator. Straight logit-log analyses are often deficient because of their high sensitivity to small errors in the end-point parametes B0 and NSB (the actual measured activity in the tubes). The literature suggests techniques for adjusting these end-point parameters, but they require too much computing time and programming space to be used with a desk-top programmable calculator. The extension to the logit-log model presented here is easily handled by the programmable calculator and provides a good estimate of the change required in B0 and NSB to obtain a better fit. The program requires 1.5 min to run on our desk-top programmable calculator, and has resulted in improved data analysis for all of the 11 types of radioimmunoassay studied.

End-point parameter adjustment on a small desk-top programmable calculator for logit-log analysis of radioimmunoassay data

We describe an improved method of logit-log curve fitting, by adjusting end-point parameters in radioimmunoassay studies, for use with a small desk-top programmable calculator. Straight logit-log analyses are often deficient because of their high sensitivity to small errors in the end-point parametes B0 and NSB (the actual measured activity in the tubes). The literature suggests techniques for adjusting these end-point parameters, but they require too much computing time and programming space to be used with a desk-top programmable calculator. The extension to the logit-log model presented here is easily handled by the programmable calculator and provides a good estimate of the change required in B0 and NSB to obtain a better fit. The program requires 1.5 min to run on our desk-top programmable calculator, and has resulted in improved data analysis for all of the 11 types of radioimmunoassay studied.