Clinical group and modified TNM stage for rhabdomyosarcoma: A review from the Children's Oncology Group.

The Children's Oncology Group (COG) uses Clinical Group (CG) and modified Tumor Node Metastasis (TNM) stage to classify rhabdomyosarcoma (RMS). CG is based on surgicopathologic findings and is determined after the completion of initial surgical procedure(s) but prior to chemotherapy and/or radiation therapy. The modified TNM stage is based on clinical and radiographic findings and is assigned prior to any treatment. These systems have evolved over several decades. We review the history, evolution, and rationale behind the current CG and modified TNM classification systems used by COG for RMS. Data from the seven most recently completed and reported frontline COG trials (D9602, D9802, D9803, ARST0331, ARST0431, ARST0531, ARST08P1) were analyzed, and confirm that CG and modified TNM stage remain relevant and useful for predicting prognosis in RMS. We propose updates based on recent data and discuss factors warranting future study to further optimize these classification systems.

Hereditary Thrombotic Thrombocytopenic Purpura in a 9-Month-old: Diagnosing and Managing an Ultra-rare Disorder.

Hereditary thrombotic thrombocytopenic purpura is an ultra-rare disorder caused by biallelic mutations in the ADAMTS13 gene. Because it can be difficult to diagnose, plasma ADAMTS13 activity assessment should be considered in patients with thrombocytopenia, anemia, and schistocytes on peripheral blood smear. We present the diagnostic evaluation of a patient with hereditary thrombotic thrombocytopenic purpura. Genetic testing revealed one known pathogenic mutation and one novel mutation of ADAMTS13 classified as likely pathogenic on the basis of parental genetic testing and in silico analyses. We further discuss off-label use of prophylactic plasma-derived Factor VIII (Koate-DVI) and the benefit of rare disease registries.

Consult and procedure incidence outcomes following establishment of a fertility preservation program for children with cancer.

PURPOSE: Fertility is a quality of life outcome adversely affected by cancer therapy. Many childhood cancer patients, however, are not offered options to preserve their fertility. Providers acknowledge difficulty discussing impaired fertility to patients due to lack of knowledge of available options. Our objective was to review the impact of a pediatric multidisciplinary fertility preservation program on providers' fertility preservation counseling and discussion of options. METHODS: A retrospective medical chart review was conducted for pediatric cancer patients prior to and following program establishment. Fertility preservation discussions, consults, and incidence were noted. Following filtering and stratification, 198 and 237 patients were seen prior to and following program establishment, respectively. RESULTS: Following program establishment, provider-patient discussions of impaired fertility (p = 0.007), fertility preservation consults (p = 0.01), and incidence of fertility preservation procedures (p < 0.001) increased among patients. Furthermore, the number of patients who received fertility preservation consults after receiving gonadotoxic treatment decreased (p < 0.001). This trend was particularly noted in pre-pubertal and female patients, for whom fertility preservation options are limited without an established program. CONCLUSION: The establishment of a formal program greatly improved access to fertility preservation consults and procedures in children with cancer.

Pelvis Ewing sarcoma: Local control and survival in the modern era.

PURPOSE: Local control for Ewing sarcoma (ES) has improved in modern studies. However, it is unclear if these gains have also been achieved for pelvis tumors. The purpose of this study is to evaluate local control and survival in pelvis ES patients treated in the modern era. METHODS: All pelvis ES patients diagnosed from 1990 to 2012 and seen at Mayo Clinic were identified. Factors relevant to survival and local control were analyzed. RESULTS: The cohort consisted of 48 patients. Fifty-two percent had metastatic disease at diagnosis. The 5-year overall survival and event-free survival was 73% and 65%, respectively, for localized disease. The 5-year cumulative incidence of local recurrence was 19%, with a 26% incidence for radiation, 13% for surgery, and 0% for surgery + radiation (P = 0.54). All local failures occurred in-field. Sacral involvement by tumor trended toward a higher incidence of local recurrence (hazard ratio 3.06, P = 0.09). Patients treated with definitive radiation doses ≥5,600 cGy had a lower incidence of local recurrence (17% vs. 28%, P = 0.61). CONCLUSIONS: Our study demonstrates excellent survival for localized tumors in the modern era. Anatomical localization within the pelvis likely correlates with outcomes. Local control remains problematic, especially for patients treated with definitive radiation. Though statistically not significant, surgery + radiation and definitive radiation dose ≥5,600 cGy were associated with the lowest incidence of local failure, suggesting treatment intensification may improve local control for pelvis ES.

Management of pediatric hepatocellular carcinoma: A multimodal approach.

HCC is rare in the pediatric population, but is the second most common liver malignancy in children. Survival rates for primary unresectable HCC have been dismal. The objective of this study was to describe our experience with a multimodal approach for the management of unresectable HCC in two adolescent patients and to review the literature. Both patients are currently alive with no recurrence at 51 and 29 months post-transplant. Multimodality treatment involving chemotherapy with doxorubicin, cisplatin, and sorafenib; TACE; timely liver transplantation; and post-transplant therapy with sorafenib and mTOR inhibitors may help improve outcomes and prolong survival in pediatric patients with unresectable HCC.

Membranous nephropathy associated with angiomatoid fibrous histiocytoma in a pediatric patient.

BACKGROUND: Though membranous nephropathy is a much more common cause of nephrotic syndrome in the adult population, it accounts for only a small fraction of cases in pediatrics. CASE-DIAGNOSIS/TREATMENT: We report a case of a 16-year-old boy with nephrotic syndrome due to membranous nephropathy in the setting of a rare tumor, angiomatoid fibrous histiocytoma. This patient's nephrotic-range proteinuria completely resolved following resection of this tumor. Angiomatoid fibrous histiocytoma, while known to cause other paraneoplastic syndromes such as anemia, has never been reported to cause membranous nephropathy. CONCLUSIONS: This case highlights a novel and treatable secondary cause of membranous nephropathy. Because secondary causes are more common in children than in adults, a high index of suspicion for other underlying pathology including malignancy should be considered. It also suggests that urinalysis may be a helpful screening tool in cases of angiomatoid fibrous histiocytoma.

Does body mass index at diagnosis or weight change during therapy predict toxicity or survival in intermediate risk rhabdomyosarcoma? A report from the Children's Oncology Group Soft Tissue Sarcoma Committee.

BACKGROUND: Weight loss prevalence and its impact on toxicities and survival in intermediate risk rhabdomyosarcoma (IRMS) patients are unknown. We evaluated the association between weight change during therapy and number of toxicities, hospital days, infections, and overall survival and between baseline body mass index (BMI) and survival in patients treated on Children's Oncology Group trial D9803. PROCEDURE: Four hundred sixty-eight IRMS patients age ≥2 and <21 years treated on D9803 had required data. Regression models evaluated association between weight loss from baseline and toxicities, hospital days, infections, and survival. Kaplan-Meier curves and regression models evaluated baseline BMI percentile's association with survival. RESULTS: Thirty-five percent and 37% of patients had >5% weight loss at 12 and 24 weeks, respectively, with 16% and 19% losing >10% weight respectively. Greater than 10% weight loss at 24 weeks was associated with more toxicities and hospital days during subsequent therapy but not infection rate or survival. Baseline underweight patients (<5th percentile BMI) had borderline inferior survival compared with baseline average weight patients while there was no difference in survival seen between average weight and overweight or obese patients. CONCLUSIONS: Nearly one in five IRMS patients experienced >10% weight loss on therapy. This was associated with increased toxicity but not decreased survival compared with patients who had less weight loss. Baseline BMI percentile trended toward a significant association with survival. Future studies might investigate nutritional impact on quality of life and if weight loss is preventable by early nutritional intervention.

Proton Whole-Lung Irradiation: Initial Report of Outcomes.

PURPOSE: Whole-lung irradiation is typically used in pediatric patients to decrease the risk of future lung metastases, but radiation dose to normal tissue is associated with long-term risks. Proton whole-lung irradiation (PWLI) provides an opportunity to decrease radiation dose to normal tissue and potentially decrease late toxicity. METHODS AND MATERIALS: This retrospective study included patients treated with spot-scanning PWLI at a single institution. Toxicity and oncologic outcomes were reviewed. Intensity modulated radiation therapy (IMRT) plans were created prospectively or retrospectively for dosimetric comparisons. Simple paired t tests were performed to assess differences between IMRT and PWLI dosimetric parameters. RESULTS: Twelve patients treated with PWLI were included in this study. Median age was 15 years (range, 3-34). Most (75%) had Ewing sarcoma. Most (92%) received 15 Gy in 10 fractions PWLI, and 3 (25%) received a focal pulmonary boost. Median follow-up was 16.5 months (range, 0-40.4 months). At last follow-up, 1 patient died of disease, while 11 were still alive (7 without disease, 4 with ongoing disease). During and immediately after treatment, 5 patients developed fatigue, 2 patients developed cough, and 1 patient developed nausea. Each treatment-related adverse event was Common Terminology Criteria for Adverse Events (version 5.0) grade 1 and resolved within 3 weeks of treatment completion. No patients have experienced clinical or radiographic pneumonitis or evidence of clinically apparent cardiac toxicity. Compared with IMRT plans, PWLI decreased mean dose to the heart, coronary artery, cardiac valve, left ventricle, aorta, breast, esophagus, kidney, liver, pancreas, thyroid, stomach, and spleen (all P < .001), without sacrificing target coverage. CONCLUSIONS: PWLI is feasible to deliver, decreases dose to normal tissue compared with IMRT, and appears to be well-tolerated. PWLI provides potential for decreased late toxicity and merits further investigation.

Rhabdomyosarcoma in infants younger than 1 year: a report from the Children's Oncology Group.

BACKGROUND: Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children, occurs less commonly in infants. Historically, poorer outcomes have been reported for infants diagnosed with RMS than for older children. METHODS: The authors analyzed the characteristics, treatment administered, outcomes, and patterns of failure for infants aged < 1 year with nonmetastatic RMS who received multimodal therapy on Intergroup Rhabdomyosarcoma Study (IRS) protocols IRS-IV, D9602, and D9803. RESULTS: Seventy-six infants with nonmetastatic RMS were treated on the 3 protocols from 1991 to 2005. Their median age was 7.4 months (range, 0.1-12 months). Tumor histology included embryonal (57%), alveolar (21%), and undifferentiated sarcoma/other (22%). A parameningeal primary tumor site was less common in this infant cohort (3%) than in all patients who were treated on IRS-IV (25%). The estimated 5-year failure-free survival and overall survival rates (95% confidence interval [CI]) were 57% (95% CI, 44%-67%) and 76% (95% CI, 65%-85%), respectively, for infants compared with 81% (95% CI, 79%-83%) and 87% (95% CI, 85%-89%), respectively, for children ages 1 to 9 years. Twenty-three of 32 infants with treatment failure had local recurrence/progression with distant failure (n = 3) or without distant failure (n = 20). The overall local failure rate was 30%. The median time to treatment failure was 13 months. The failure-free survival rate was worse for infants who had IRS Group III tumors and for those who received less than protocol-recommended radiation therapy. CONCLUSIONS: Infants with RMS appeared to have worse outcomes than older patients, in part because of high rates of local failure. The authors concluded that concerns regarding morbidity in infants and reluctance to use aggressive local control measures may lead to higher rates of local failure.

Dactinomycin and vincristine toxicity in the treatment of childhood cancer: a retrospective study from the Children's Oncology Group.

BACKGROUND: Dactinomycin (AMD) and vincristine (VCR) have been used for the treatment of childhood cancer over the past 40 years but evidence-based dosing guidance is lacking. METHODS: Patient AMD and VCR dose and drug-related adverse event (AE) information from four rhabdomyosarcoma (RMS) and two Wilms tumor (WT) studies were assembled. Statistical modeling was used to account for differences in AE data collection across studies, develop rate models for grade 3/4 CTCAE v3 hepatic- (AMD) and neuro- (VCR) toxicity, assess variation in toxicity rates over age and other factors, and predict toxicity risk under current dosing guidelines. RESULTS: For the same dose/body size, AMD toxicity rates were higher in patients <1 year than older patients and VCR toxicity rates increased with age. The statistical model provided estimates for AMD and VCR toxicity risk under current dosing schedules and indicated that patients of smaller body size were at lower risk of VCR toxicity than larger patients of the same age. The rate of AMD toxicity was highest early in treatment and was lower in patients who tolerated initial AMD without toxicity. CONCLUSION: The observed decrease in AMD toxicity rate with cumulative dose may indicate sensitivity in a subgroup of patients while the observed increase in VCR toxicity risk with age may indicate changing sensitivity to VCR. Current dosing practices result in a fairly uniform toxicity profile within age group. However, PK/PD studies should be done to provide further provide further information on best dosing guidelines.

Establishment of a Pediatric Ovarian and Testicular Cryopreservation Program for Malignant and Non-Malignant Conditions: The Mayo Clinic Experience.

STUDY OBJECTIVES: To describe the structure of a pediatric fertility preservation (FP) program and to share safety and patient satisfaction data. DESIGN: The FP program operates under prospective research protocols approved by the Mayo Clinic Institutional Review Board (IRB). SETTING: The FP program is a multidisciplinary effort between pediatric gynecology, reproductive endocrinology, pediatric urology, pediatric surgery, and laboratory medicine. PARTICIPANTS: The FP program enrolls patients between 0-17 years of age who have been diagnosed with a fertility-threatening condition and/or are scheduled to undergo gonadotoxic treatment. INTERVENTIONS: FP is offered in the form of ovarian tissue cryopreservation (OTC) and testicular (TTC) tissue cryopreservation. MAIN OUTCOME MEASURES: The outcome measures are the safety of the procedure and results of patient surveys conducted by phone using a standard list of questions to assess attitudes towards FP. RESULTS: To date, we have enrolled 38 OTC and 37 TTC patients. The median age (range) of OTC and TTC patients was 11 years (0.83-17 years) and 10 years (0.92-17 years) at the time of enrollment, respectively. Childhood cancers currently represent 88% of the fertility-threatening diagnoses. Meanwhile, patients with non-malignant conditions include those with gender dysphoria, aplastic anemia, and Turner's syndrome. To date, no serious adverse events (SAEs) have been reported following surgery. According to n = 34 one-year follow-ups, 100% of parents felt that FP was a good decision. CONCLUSION: Consistent with the literature, our data suggests FP is safe and improves the quality of care provided to pediatric patients for their fertility-threatening diagnoses and/or treatments. TRIAL REGISTRATION: NCT02872532, NCT02646384.

Refinement of risk stratification for childhood rhabdomyosarcoma using FOXO1 fusion status in addition to established clinical outcome predictors: A report from the Children's Oncology Group.

BACKGROUND: Previous studies of the prognostic importance of FOXO1 fusion status in patients with rhabdomyosarcoma (RMS) have had conflicting results. We re-examined risk stratification by adding FOXO1 status to traditional clinical prognostic factors in children with localized or metastatic RMS. METHODS: Data from six COG clinical trials (D9602, D9802, D9803, ARST0331, ARTS0431, ARST0531; two studies each for low-, intermediate- and high-risk patients) accruing previously untreated patients with RMS from 1997 to 2013 yielded 1727 evaluable patients. Survival tree regression for event-free survival (EFS) was conducted to recursively select prognostic factors for branching and split. Factors included were age, FOXO1, clinical group, histology, nodal status, number of metastatic sites, primary site, sex, tumor size, and presence of metastases in bone/bone marrow, soft tissue, effusions, lung, distant lymph nodes, and other sites. Definition and outcome of the proposed risk groups were compared to existing systems and cross-validated results. RESULTS: The 5-year EFS and overall survival (OS) for evaluable patients were 69% and 79%, respectively. Extent of disease (localized versus metastatic) was the first split (EFS 73% vs 30%; OS 84% vs. 42%). FOXO1 status (positive vs negative) was significant in the second split both for localized (EFS 52% vs 78%; OS 65% vs 88%) and metastatic disease (EFS 6% vs 46%; OS 19% vs 58%). CONCLUSIONS: After metastatic status, FOXO1 status is the most important prognostic factor in patients with RMS and improves risk stratification of patients with localized RMS. Our findings support incorporation of FOXO1 status in risk stratified clinical trials.

Relative red blood cell enzyme levels as a clue to the diagnosis of pyruvate kinase deficiency.

Evaluation of two patients with transfusion dependent anemia revealed RBC pyruvate kinase to be 33% and 41% of the mean normal value, with normal or high values of other RBC enzymes. Parental PK activities were just below normal in three of four of the parents. Subsequent DNA analysis revealed both patients to be compound heterozygotes for PKLR gene mutations, two of which are previously undescribed. Borderline low pyruvate kinase activities with increased in other RBC enzyme activities should prompt consideration of measurement of parental enzyme activities, and confirmation by DNA analysis if available.

Comparison of results of a pilot study of alternating vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide with IRS-IV in intermediate risk rhabdomyosarcoma: a report from the Children's Oncology Group.

BACKGROUND: Over 50% of patients with rhabdomyosarcoma (RMS) have intermediate risk disease, with a 3-year failure-free survival (FFS) of 50%-70% depending on histology. Doxorubicin is active against RMS, but its role in improving outcome remains controversial. Ifosfamide is as active as cyclophosphamide in RMS, with the Fourth Intergroup RMS Study (IRS-IV) showing equivalent outcomes for patients treated with ifosfamide for the first 28 weeks compared to cyclophosphamide. Treatment with alternating cycles of non-cross-resistant chemotherapy has been used in a number of diseases with good results. PROCEDURE: The results of a pilot study utilizing alternating courses of vincristine, doxorubicin, cyclophosphamide, and etoposide/ifosfamide (VDC/IE) were compared for outcome and patient characteristics to a group of similar matched patients treated on IRS-IV. RESULTS: The 5-year FFS for patients with parameningeal (PM) primaries on IRS-IV and the VDC/IE study were 72% and 82%, respectively (P = 0.26); for patients with non-PM primaries, the estimated risk of failure for VDC/IE study versus IRS-IV was 0.54. Combining all disease sites and performing analysis for relative risk of failure for 46 VDC/IE patients and 342 IRS-IV patients, the relative risk of failure for the VDC/IE study compared to the IRS-IV study is 0.5 (P = 0.06). CONCLUSIONS: VDC/IE is as effective therapy for intermediate risk RMS as IRS-IV therapy. It is being explored along with irinotecan in relapsed patients and newly diagnosed high-risk patients.

Fifty years of rhabdomyosarcoma studies on both sides of the pond and lessons learned.

We review and summarize the highlights of almost five decades of cooperative group trials in rhabdomyosarcoma on both sides of the Atlantic, concentrating on chemotherapy regimens, what has been learned, and where remaining challenges are. The most important achievements have been to decrease or omit the dose of alkylator therapy for many patients, to clarify after much controversy that doxorubicin does not improve the outcome of patients even in the highest risk groups, and to show that high dose chemotherapy and stem cell rescue do not improve the outcome of the highest risk patients. In North America, vincristine/actinomycin/cyclophosphamide (VAC) remains an important part of therapy, whereas in Europe the alkylating agent of choice is ifosfamide. The highest risk patients, namely those with the poorest prognostic score, have had no improvement in outcome since the first cooperative group trial in 1972 and remain the greatest challenge. Philosophical differences between European and North American strategies still revolve somewhat around the total burden of therapy received, that is should certain groups of patients be spared aggressive local control in order to reduce late effects, recognizing that it is not possible to identify priori the children that can be cured with this approach exposing the whole population to a higher risk of relapse. Collaboration and joining resources may help answer some difficult questions.

Extraskeletal Osteosarcoma: Outcomes and the Role of Chemotherapy.

OBJECTIVES: Extraskeletal osteosarcoma (EO) is a malignant neoplasm that produces osteoid, bone, and chondroid material without direct attachment to bone or periosteum. Surgical resection is the mainstay of treatment; the role of chemotherapy is not well defined. Therefore, we evaluated the impact of chemotherapy in the survival of patients with EO. METHODS: All EO patients seen at Mayo Clinic between 1990 and 2014 were assessed. Forty-three patients were included after all archived pathology slides were reviewed to confirm the diagnosis of EO. RESULTS: Of 43 patients, 37 patients had localized disease and 6 patients had metastatic disease at diagnosis. Chemotherapy was used in 73% and 75% of patients, respectively. Chemotherapy was predominantly anthracycline based, and included platinum in 22 patients (84%).Median overall survival (OS) and progression-free survival (PFS) were 50 months (95% confidence interval, 25-99), and 21 months (95% confidence interval, 13-not reached), respectively. There was a trend towards longer OS and PFS in patients who received chemotherapy. Those who received platinum-based therapy had remarkably prolonged OS (median, 182 vs. 18 mo; 5-year, 61% vs. 0%; P=0.01) and PFS (median, not reached vs. 10 mo; 5-year, 56% vs. 0%; P=0.005). Baseline characteristics were similar in the platinum and nonplatinum group.In patients who received chemotherapy, relapse/recurrence rate was lower in the platinum-based group (41%) as opposed to the nonplatinum-based group (100%; P=0.02). In the neoadjuvant setting, the overall response rate of platinum-containing regimens was 27%. CONCLUSIONS: Our results suggest a clinical benefit when platinum-based chemotherapy is incorporated in the management of patients with EO. We plan to validate this further with an expanded multicenter analysis.

Addition of Vincristine and Irinotecan to Vincristine, Dactinomycin, and Cyclophosphamide Does Not Improve Outcome for Intermediate-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group.

Purpose Intermediate-risk rhabdomyosarcoma (RMS) includes patients with either nonmetastatic, unresected embryonal RMS (ERMS) with an unfavorable primary site or nonmetastatic alveolar RMS (ARMS). The primary aim of this study was to improve the outcome of patients with intermediate-risk RMS by substituting vincristine and irinotecan (VI) for half of vincristine, dactinomycin, and cyclophosphamide (VAC) courses. All patients received a lower dose of cyclophosphamide and earlier radiation therapy than in previous trials. Patients and Methods Patients were randomly assigned at study entry to either VAC (cumulative cyclophosphamide dose, 16.8 g/m2) or VAC/VI (cumulative cyclophosphamide dose, 8.4 g/m2) for 42 weeks of therapy. Radiation therapy started at week 4, with individualized local control plans permitted for patients younger than 24 months. The primary study end point was event-free survival (EFS). The study design had an 80% power (5% one-sided α-level) to detect an improved long-term EFS from 65% (with VAC) to 76% (with VAC/VI). Results A total of 448 eligible patients were enrolled in the study. At a median follow-up of 4.8 years, the 4-year EFS was 63% with VAC and 59% with VAC/VI ( P = .51), and 4-year overall survival was 73% for VAC and 72% for VAC/VI ( P = .80). Within the ARMS and ERMS subgroups, no difference in outcome by treatment arm was found. Severe hematologic toxicity was less common with VAC/VI therapy. Conclusion The addition of VI to VAC did not improve EFS or OS for patients with intermediate-risk RMS. VAC/VI had less hematologic toxicity and a lower cumulative cyclophosphamide dose, making VAC/VI an alternative standard therapy for intermediate-risk RMS.

Delayed radiotherapy following dose intensive chemotherapy for parameningeal rhabdomyosarcoma (PM-RMS) of childhood.

PURPOSE: To evaluate the local control rates and survival rates of patients with Group III parameningeal rhabdomyosarcoma (PM-RMS) treated with a dose intensive chemotherapy regimen followed by irradiation. MATERIALS AND METHODS: Twenty-six patients with group III, PM-RMS were enrolled in a prospective pilot trial at the Mayo Clinic, Rochester, MN and Children's Hospital and Regional Medical Center Seattle, WA. The median age at diagnosis was 8.5 years (range 1.5-19 years). The male to female patient ratio was 1.6:1. Twenty-three patients had embryonal histology with the remaining three alveolar. Risk factors indicating high risk disease included intracranial extension (10 patients), base of skull erosion (12 patients), and cranial nerve palsy (10 patients). The median follow-up period for all patients was 82 months (range 17-148 months). Patients were treated with an intensified chemotherapy regimen followed by definitive local irradiation at week 12 following further chemotherapy. The median time from initiation of chemotherapy to irradiation was 16 weeks (range 6-23). The median dose delivered was 50.4Gy (50.4-66.6Gy). RESULTS: Response was assessed after the fourth course of chemotherapy. Three patients exhibited a complete response, 22 a partial response, and 1 patient had no response after two cycles of chemotherapy and proceeded to irradiation at week 6. The 5-year estimated event free survival was 81% (+/-15%, 95% CI). Two patients died from progressive metastatic disease; 1 patient died from secondary malignancy; and 2 patients died from locally progressive disease. The 5-year local control rate was 92% (+/-10.6%, 95% CI). CONCLUSIONS: Treatment of group III PM-RMS patients with neo-adjuvant, intensive chemotherapy with a delay in irradiation resulted in excellent local-regional control rates and survival rates and may allow for a response-based radiotherapy approach.

Intrathecal mafosfamide: a preclinical pharmacology and phase I trial.

PURPOSE: Preclinical studies of mafosfamide, a preactivated cyclophosphamide analog, were performed to define a tolerable and potentially active target concentration for intrathecal (IT) administration. A phase I and pharmacokinetic study of IT mafosfamide was performed to determine a dose for subsequent phase II trials. PATIENTS AND METHODS: In vitro cytotoxicity studies were performed in MCF-7, Molt-4, and rhabdomyosarcoma cell lines. Feasibility and pharmacokinetic studies were performed in nonhuman primates. These preclinical studies were followed by a phase I trial in patients with neoplastic meningitis. There were five dose levels ranging from 1 mg to 6.5 mg. Serial CSF samples were obtained for pharmacokinetic studies in a subset of patients with Ommaya reservoirs. RESULTS: The cytotoxic target exposure for mafosfamide was 10 micromol/L. Preclinical studies demonstrated that this concentration could be easily achieved in ventricular CSF after intraventricular dosing. In the phase I clinical trial, headache was the dose-limiting toxicity. Headache was ameliorated at 5 mg by prolonging the infusion rate to 20 minutes, but dose-limiting headache occurred at 6.5 mg dose with prolonged infusion. Ventricular CSF mafosfamide concentrations at 5 mg exceeded target cytotoxic concentrations after an intraventricular dose, but lumbar CSF concentrations 2 hours after the dose were less than 10 micromol/L. Therefore, a strategy to alternate dosing between the intralumbar and intraventricular routes was tested. Seven of 30 registrants who were assessable for response had a partial response, and six had stable disease. CONCLUSION: The recommended phase II dose for IT mafosfamide, administered without concomitant analgesia, is 5 mg over 20 minutes.

Marrow irradiation with high-dose 153Samarium-EDTMP followed by chemotherapy and hematopoietic stem cell infusion for acute myelogenous leukemia.

In four patients, aged 15 - 20 years, with high-risk acute myeloid leukemia (AML), high-dose samarium 153-labelled ethylenediaminetetramethylenephosphonate (153Sm-EDTMP) was used for targeted marrow irradiation before preparative chemotherapy conditioning regimens and allogeneic (three patients) or autologous (one patient) hematopoietic stem cell transplantation. The dose of 153Sm-EDTMP was 703 MBq/kg (n = 1) or 1110 MBq/kg (n = 3). No side-effects occurred during the 30-min infusion of 153Sm-EDTMP. Samarium - melphalan regimens were given to three patients; one had 153Sm-EDTMP - busulfan + cyclophosphamide. Total body radioactivity was below the 133 MBq safe limit before infusion of stem cells (day 14 after 153Sm-EDTMP). No hemorrhagic cystitis, nephrotoxicity or serious infections occurred. Leukocyte engraftment (white blood cell count >0.5 x 10(9)/l) occurred between 12 and 23 days after stem cell infusion (mean of 17 days). Complete cytogenetic and morphologic remission of AML was evident on follow-up marrow aspirate and biopsy specimens from all patients. In two of the four study patients, the disease remains in complete remission and the patients have an excellent quality of life (Eastern Cooperative Oncology Group performance status 0; no medications) and no organ toxicity more than 2 years and more than 4 years, respectively, after their blood and bone marrow transplantations. Thus, in adolescents and adults, 153Sm-EDTMP may provide a relatively simple and effective means for using irradiation to eliminate AML within the marrow.