SunRISe-4: TAR-200 plus cetrelimab or cetrelimab alone as neoadjuvant therapy in patients with muscle-invasive bladder cancer (MIBC) who are ineligible for or refuse neoadjuvant platinum-based chemotherapy

TPS584

Background: Standard of care for patients (pts) with MIBC is radical cystectomy (RC) with neoadjuvant systemic platinum-based chemotherapy (PBC); however, systemic chemotherapy is associated with significant toxicity. TAR-200 is an intravesical drug delivery system that provides local continuous gemcitabine release within the bladder. SunRISe-4 (NCT04919512) is an open-label, multicenter, randomized phase 2 study designed to assess the efficacy and safety of neoadjuvant TAR-200 + systemic cetrelimab (CET [anti–programmed death-1 antibody]) vs neoadjuvant CET alone in pts with MIBC scheduled for RC who are ineligible for or refuse neoadjuvant PBC. Methods: Eligibility criteria: age ≥18 years, Eastern Cooperative Oncology Group performance status of 0 or 1, histologically confirmed cT2-T4a MIBC with absence of nodal or metastatic disease at screening, and residual intravesical tumor volume of ≤3 cm prior to randomization. Pts will be stratified by completeness of transurethral resection of bladder tumor (TURBT; visibly complete vs incomplete and ≤3 cm) and tumor stage (cT2 vs cT3-4a) at initial diagnosis. Pts (N≈160) will be randomized 5:3 to receive TAR-200 + CET (Cohort 1, n≈100) or CET alone (Cohort 2, n≈60). In Cohort 1, TAR-200 (225 mg gemcitabine) will be placed intravesically at the initial treatment visit; TAR-200 will be removed and replaced over a 12-week period. In both cohorts, CET will be serially dosed intravenously over the same timeframe. Primary disease assessments include axial imaging (at screening and Week 6), centralized review of TURBT (initial diagnostic TURBT or debulking TURBT for pts with lesions >3 cm after initial TURBT) as well as RC and nodal tissue specimens. After RC, all pts will have follow-up visits from Weeks 4 to 108 post RC (end of study). The primary outcome measure is the pathologic complete response rate at time of RC. Secondary outcome measures include safety, tolerability, and recurrence-free survival (per Response Evaluation Criteria in Solid Tumors 1.1 or histologic evidence). Exploratory outcome measures include patient-reported cancer-related quality of life (Functional Assessment of Cancer Therapy–Bladder questionnaire) and pathologic overall response rate at RC. Overall survival and time to symptomatic progression, pharmacokinetics, biomarker analysis, and immunogenicity will also be evaluated. As of September 12, 2022, 2 of 160 planned pts have been enrolled and randomized, and recruitment is ongoing at ≈95 sites. Clinical trial information: NCT04919512 .

Daratumumab With Cetrelimab, an Anti-PD-1 Monoclonal Antibody, in Relapsed/Refractory Multiple Myeloma

BACKGROUND

Daratumumab is approved for relapsed or refractory multiple myeloma (RRMM) as monotherapy or in combination regimens. We evaluated daratumumab plus cetrelimab, a programmed death receptor-1 inhibitor, in RRMM.

PATIENTS AND METHODS

This open-label, multiphase study enrolled adults with RRMM with ≥ 3 prior lines of therapy. Part 1 was a safety run-in phase examining dose-limiting toxicities of daratumumab (16 mg/kg intravenously weekly for cycles 1-2, biweekly for cycles 3-6, and monthly thereafter) plus cetrelimab (240 mg intravenously biweekly, all cycles). In Parts 2 and 3, patients were to be randomized to daratumumab with or without cetrelimab (same schedule as Part 1). Endpoints included safety, overall response rate, pharmacokinetics, and biomarker analyses.

RESULTS

Nine patients received daratumumab plus cetrelimab in the safety run-in, and 1 received daratumumab in Part 2 before administrative study termination following a data monitoring committee's global recommendation to stop any trial including daratumumab combined with inhibitors of programmed death receptor-1 or its ligand (programmed death-ligand 1). The median follow-up times were 6.7 months (safety run-in) and 0.3 months (Part 2). No dose-limiting toxicities occurred. All 10 patients had ≥ 1 treatment-emergent adverse event; 7 patients had grade 3 to 4 treatment-emergent adverse events, and none led to treatment discontinuation or death. In the safety run-in, 7 (77.7%) patients had ≥ 1 infusion-related reaction (most grade 1-2), and 1 had a grade 2 immune-mediated reaction. Among safety run-in patients, the overall response rate was 44.4%.

CONCLUSIONS

No new safety concerns were identified for daratumumab plus cetrelimab in RRMM. The short study duration and small population limit complete analysis of this combination.

Daratumumab plus bortezomib, melphalan, and prednisone in East Asian patients with non-transplant multiple myeloma: subanalysis of the randomized phase 3 ALCYONE trial

In the ALCYONE trial, daratumumab plus bortezomib, melphalan, and prednisone (D-VMP) reduced the risk of disease progression or death by 50% versus bortezomib, melphalan, and prednisone (VMP) in patients with transplant-ineligible newly diagnosed multiple myeloma. Here, we report a subanalysis of East Asian patients from ALCYONE. After a median follow-up of 17.1 and 15.9 months for Japanese (n = 50) and Korean (n = 41) patients, respectively, median progression-free survival for D-VMP versus VMP was not reached (NR) versus 20.7 months in Japanese patients and NR versus 14.0 months in Korean patients. The overall response rate for D-VMP versus VMP was 96% versus 92% in Japanese patients and 91% versus 61% in Korean patients. Using next-generation sequencing, minimal residual disease negativity at 10⁻⁵ sensitivity for D-VMP versus VMP was 33% versus 8% among Japanese patients and 17% versus 0% among Korean patients. Rates of any grade and grade 3/4 pneumonia were consistent with the rates observed for the global safety population. Similar efficacy and safety findings were observed in the combined Japanese and Korean subgroup and ≥ 75 years of age subgroup. In conclusion, D-VMP was safe and efficacious in East Asian patients, consistent with the global ALCYONE population.

Bortezomib, lenalidomide, and dexamethasone (VRd) ± daratumumab (DARA) in patients (pts) with transplant-eligible (TE) newly diagnosed multiple myeloma (NDMM): A multicenter, randomized, phase III study (PERSEUS)

TPS8055

Background: DARA, a human, CD38-targeting, IgGκ monoclonal antibody, is approved in many countries for use as monotherapy in relapsed/refractory MM (RRMM), and in combination with standard-of-care regimens in RRMM and transplant-ineligible NDMM. Given the initial safety and efficacy observed with DARA plus VRd (D-VRd) in the safety run-in cohort of the ongoing phase 2 GRIFFIN study in TE NDMM pts, the phase 3 PERSEUS study will evaluate the efficacy and safety of D-VRd versus VRd alone in TE NDMM. Methods: This is an ongoing multicenter, open-label, randomized phase 3 study of D-VRd versus VRd alone in TE NDMM pts. Approximately 690 pts across Europe will be stratified by ISS stage and cytogenetic risk (high risk defined as presence of del17p, t[4;14], or t[14;16]) and randomized in a 1:1 ratio. All pts will receive VRd (V: 1.3 mg/m2 SC Days 1, 4, 8, 11; R: 25 mg PO Days 1-21; d: 40 mg PO Days 1-4, 9-12) for 4 pre-transplant induction and 2 post-transplant consolidation cycles (all 28-d cycles), followed by R (10 mg PO Days 1-28) maintenance until progressive disease (PD). Pts in the DARA group will also receive subcutaneous DARA (1,800 mg co-formulated with recombinant human hyaluronidase PH20 [rHuPH20; Halozyme]) QW in Cycles 1-2, Q2W in Cycles 3-6, and Q4W in maintenance Cycles 7+ until PD. After induction, pts will undergo melphalan 200 mg/m2 conditioning and autologous stem cell transplantation (ASCT). Pts in the DARA group who achieve sustained minimal residual disease (MRD) negativity (10–5 threshold; assessed by NGS) for 12 months after ≥24 months of maintenance will stop DARA but continue R maintenance until PD; upon loss of CR or MRD-negative status, pts will restart DARA treatment. All pts will receive preinfusion medications. The primary endpoint is progression-free survival (PFS). Secondary endpoints include MRD-negative rate, overall response rate, PFS on next line of therapy, overall survival, time to and duration of response, health-related quality of life, pharmacokinetics, immunogenicity, stem cell yield after mobilization, time to engraftment post-ASCT, and safety. Clinical trial information: NCT03710603.

Daratumumab plus Bortezomib, Melphalan, and Prednisone for Untreated Myeloma

BACKGROUND

The combination of bortezomib, melphalan, and prednisone is a standard treatment for patients with newly diagnosed multiple myeloma who are ineligible for autologous stem-cell transplantation. Daratumumab has shown efficacy in combination with standard-of-care regimens in patients with relapsed or refractory multiple myeloma.

METHODS

In this phase 3 trial, we randomly assigned 706 patients with newly diagnosed multiple myeloma who were ineligible for stem-cell transplantation to receive nine cycles of bortezomib, melphalan, and prednisone either alone (control group) or with daratumumab (daratumumab group) until disease progression. The primary end point was progression-free survival.

RESULTS

At a median follow-up of 16.5 months in a prespecified interim analysis, the 18-month progression-free survival rate was 71.6% (95% confidence interval [CI], 65.5 to 76.8) in the daratumumab group and 50.2% (95% CI, 43.2 to 56.7) in the control group (hazard ratio for disease progression or death, 0.50; 95% CI, 0.38 to 0.65; P<0.001). The overall response rate was 90.9% in the daratumumab group, as compared with 73.9% in the control group (P<0.001), and the rate of complete response or better (including stringent complete response) was 42.6%, versus 24.4% (P<0.001). In the daratumumab group, 22.3% of the patients were negative for minimal residual disease (at a threshold of 1 tumor cell per 10⁵ white cells), as compared with 6.2% of those in the control group (P<0.001). The most common adverse events of grade 3 or 4 were hematologic: neutropenia (in 39.9% of the patients in the daratumumab group and in 38.7% of those in the control group), thrombocytopenia (in 34.4% and 37.6%, respectively), and anemia (in 15.9% and 19.8%, respectively). The rate of grade 3 or 4 infections was 23.1% in the daratumumab group and 14.7% in the control group; the rate of treatment discontinuation due to infections was 0.9% and 1.4%, respectively. Daratumumab-associated infusion-related reactions occurred in 27.7% of the patients.

CONCLUSIONS

Among patients with newly diagnosed multiple myeloma who were ineligible for stem-cell transplantation, daratumumab combined with bortezomib, melphalan, and prednisone resulted in a lower risk of disease progression or death than the same regimen without daratumumab. The daratumumab-containing regimen was associated with more grade 3 or 4 infections. (Funded by Janssen Research and Development; ALCYONE ClinicalTrials.gov number, NCT02195479 .).

Population pharmacokinetics and exposure-response of trametinib, a MEK inhibitor, in patients with BRAF V600 mutation-positive melanoma

PURPOSE

To characterize the pharmacokinetics of oral trametinib, a first in class MEK inhibitor, identify covariates, and describe the relationship between exposure and clinical effects in patients with BRAF V600 metastatic melanoma.

EXPERIMENTAL DESIGN

Trametinib concentrations obtained in three clinical studies were included in the population pharmacokinetic analysis. Trametinib 2 mg once daily was administered in the Phase 2 and 3 studies. The impact of exposure [trough (C min) or average concentration] on response rates and progression-free survival (PFS) was examined.

RESULTS

Plasma concentrations (n = 3120) obtained in 493 patients were described using a two-compartment model. Trametinib oral clearance was lower in women relative to men (1.26-fold) and increased with body weight. There was no significant effect of age, mild or moderate renal impairment, or mild hepatic impairment on oral clearance. Between-subject variability was low (24 %). The number of responders was consistent across median exposure range, although tended to be lower at trough concentration <10 ng/mL. Disease stage was found to be a significant predictor of response with a lower response rate in patients with disease stage of M1c. Lactate dehydrogenase was significant in the analysis of PFS. Patients with observed C min above the median had longer PFS than those below median based on Phase 2 study (median 10.6 ng/mL), while the effect of exposure was not statistically significant in the Phase 3 study (median 13.6 ng/mL).

CONCLUSIONS

No dosage adjustments are required with any of the covariates tested. Clinical efficacy was associated with trametinib trough concentrations greater than 10 ng/mL.

Improved overall survival in melanoma with combined dabrafenib and trametinib

BACKGROUND

The BRAF inhibitors vemurafenib and dabrafenib have shown efficacy as monotherapies in patients with previously untreated metastatic melanoma with BRAF V600E or V600K mutations. Combining dabrafenib and the MEK inhibitor trametinib, as compared with dabrafenib alone, enhanced antitumor activity in this population of patients.

METHODS

In this open-label, phase 3 trial, we randomly assigned 704 patients with metastatic melanoma with a BRAF V600 mutation to receive either a combination of dabrafenib (150 mg twice daily) and trametinib (2 mg once daily) or vemurafenib (960 mg twice daily) orally as first-line therapy. The primary end point was overall survival.

RESULTS

At the preplanned interim overall survival analysis, which was performed after 77% of the total number of expected events occurred, the overall survival rate at 12 months was 72% (95% confidence interval [CI], 67 to 77) in the combination-therapy group and 65% (95% CI, 59 to 70) in the vemurafenib group (hazard ratio for death in the combination-therapy group, 0.69; 95% CI, 0.53 to 0.89; P=0.005). The prespecified interim stopping boundary was crossed, and the study was stopped for efficacy in July 2014. Median progression-free survival was 11.4 months in the combination-therapy group and 7.3 months in the vemurafenib group (hazard ratio, 0.56; 95% CI, 0.46 to 0.69; P<0.001). The objective response rate was 64% in the combination-therapy group and 51% in the vemurafenib group (P<0.001). Rates of severe adverse events and study-drug discontinuations were similar in the two groups. Cutaneous squamous-cell carcinoma and keratoacanthoma occurred in 1% of patients in the combination-therapy group and 18% of those in the vemurafenib group.

CONCLUSIONS

Dabrafenib plus trametinib, as compared with vemurafenib monotherapy, significantly improved overall survival in previously untreated patients with metastatic melanoma with BRAF V600E or V600K mutations, without increased overall toxicity. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01597908.).

Age is an independent prognostic factor in rhabdomyosarcoma: a report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

Although age <1 year at diagnosis has been associated with a worse prognosis in rhabdomyosarcoma (RMS), the relationship of age at diagnosis to clinical presentation and outcome has not been evaluated carefully. We reviewed data from recent Intergroup Rhabdomyosarcoma Study Committee (later called Group, IRSG) trials to examine this relationship in order to estimate prognosis more accurately and further refine treatment.

PROCEDURE

We used data from IRS-III, -IV Pilot, and -IV (1983-97, N=2,343) to study the relationship of patient age with clinical features and prognosis in a large cohort of patients treated with contemporary therapy.

RESULTS

We showed that, after adjusting for important prognostic factors, age was an independent risk factor for treatment failure and patients could be classified into three failure-risk categories based on age (i.e., <1 year; 1-9 years; >10 years). Infants and adolescents were more likely to have unfavorable features, including alveolar or undifferentiated tumors and advanced Group and Stage, and also had significantly poorer failure-free survival (FFS) than did children aged 1-9 (53 and 51% vs. 72%, P<0.001). Although there was a difference in FFS among age categories, there was no evidence that age influences outcome within the three categories.

CONCLUSIONS

Since age relates independently to outcome after adjustment for known risk factors, it is likely that other factors, including perhaps patients' tolerance of protocol-specified therapy, explain this relationship.

Efficacy of ifosfamide and doxorubicin given as a phase II "window" in children with newly diagnosed metastatic rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study Group

BACKGROUND

The cure rate for children/adolescents with localized rhabdomyosarcoma (RMS) has tripled over the past 25 years, but patients with metastatic disease at presentation have not benefited similarly, and urgently need new therapy. We evaluated a new drug pair, ifosfamide + doxorubicin, for such patients.

PROCEDURE

We estimated the complete and partial response rates (i.e., CR and PR) of 152 previously untreated children/adolescents with metastatic RMS entered on the IRS-IV pilot from July 1988 to October 1991 who received an "up-front window" of ifosfamide (1.8 gm/m(2)/day for 5 days) and doxorubicin (30 mg/m(2)/day for 2 days) given every 3 weeks for 12 weeks. This was followed by combination chemotherapy with vincristine, actinomycin D, and cyclophosphamide (VAC), given every 3 weeks for an additional 36 weeks.

RESULTS

Of 115 patients evaluable for early response at 12 weeks, 28 (20%) had CR and 66 (43%) had PR. The ultimate CR rate was 52%. Overall, about one-third of patients survived. Prognostic factor analysis revealed that patients < 10 years old (P < 0.001), those with embryonal tumors (P = 0.002), or a GU primary site (P = 0.010), and those who lacked nodal disease (P = 0.041), and those who lacked bone or bone marrow metastasis (P < 0.001) fared better than did others.

CONCLUSIONS

The 63% CR + PR rate achieved at 12 weeks and overall 5-year FFS seen with this drug pair is similar to that achieved with previously evaluated drug combinations. We conclude that ifosfamide/doxorubicin is highly active in advanced RMS, and should be considered for inclusion in frontline therapy for children with intermediate or high-risk RMS.

Mealtime behaviors of young children: a comparison of normative and clinical data

The objective of this study was to compare the behavior of healthy young children around feeding and mealtimes to the behavior of two clinical groups, children referred for feeding problems without related medical issues and those with medical issues associated with the feeding problems. Using the Behavioral Pediatrics Feeding Assessment Scale, data were obtained for 96 healthy children between the ages of 9 months and 7 years, and descriptive information is presented in the paper on these normal mealtime behaviors. In comparing this normative data to similar data obtained from the clinical groups, our primary purpose was to investigate whether children with feeding problems engage in fundamentally different behaviors (maladaptive) or similar behaviors, but at an increased frequency to normal children. Factor analysis identified five common patterns of behavior across the three groups. The difference in parental report of feeding difficulties between healthy and clinical groups appears to reflect the frequency in which the child with feeding difficulties engages in the problematic behavior, rather than fundamental differences in behaviors exhibited during mealtimes.

Up-front window trial of topotecan in previously untreated children and adolescents with metastatic rhabdomyosarcoma: an intergroup rhabdomyosarcoma study

PURPOSE

To investigate the antitumor activity and toxicity of topotecan, used alone and in combination with conventional therapy, in patients with metastatic rhabdomyosarcoma (RMS).

PATIENTS AND METHODS

Forty-eight patients younger than 21 years of age with newly diagnosed metastatic RMS received 2.0 to 2.4 mg/m(2) of topotecan intravenously daily for 5 days every 21 days before standard therapy. Two courses were given in the absence of progressive disease or excessive toxicity and response was assessed. Patients with at least a partial response (PR) to topotecan proceeded to therapy with alternating courses of vincristine 1.5 mg/m(2), dactinomycin 1.5 mg/m(2), and cyclophosphamide 2.2 g/m(2) (VAC) and vincristine 1.5 mg/m(2), topotecan 0.75 mg/m(2) daily x 5, and cyclophosphamide 250 mg/m(2) daily x 5. Patients who did not respond to topotecan received continuation therapy with VAC alone.

RESULTS

The overall response rate to topotecan was 46% (complete response, 4%; partial response 42%). Unexpectedly, patients with alveolar RMS had a higher rate of response (65%) than those with embryonal RMS (28%; P: = .08). The most common grade 3 or 4 toxicities were neutropenia (67%), anemia (33%), thrombocytopenia (25%), and infection (21%). Two-year failure-free survival and survival estimates were 24% and 46%, respectively. Response to window therapy did not correlate with survival.

CONCLUSION

The high response rate and acceptable toxicity profile of topotecan in children with advanced RMS support further evaluation of this agent in phase III trials. The superior responses in alveolar RMS are of interest.

Philadelphia chromosome-positive acute lymphoblastic leukemia in children: durable responses to chemotherapy associated with low initial white blood cell counts

To substantiate the reported sensitivity of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) to St Jude-type multiagent chemotherapy and to identify means of selecting patients most likely to benefit from such treatment, we analyzed the clinical and biologic characteristics of 12 patients with classic Ph+ ALL who were treated in either of two total therapy programs at St Jude Children's Research Hospital (1989-1994). Event-free survival estimates for this cohort were compared with historical data on 11 patients from an earlier total therapy study (Lancet 1994; 343: 331-332). The prognostic importance of age, white blood cell count and other presenting features was assessed by the logrank test in all 23 patients. Complete remissions were induced in 92% of the patients treated since 1989, compared with 82% of the historical control group (P > 0.05). There was essentially no difference in event-free survival between the study group and historical controls (4-year Kaplan-Meier estimates, 33 +/- 19% s.e. vs 36 +/- 13%). Further analysis of potentially informative risk factors identified a good-prognosis subgroup defined by an initial white blood cell count of < or =25 x 10(9)/l and a 4-year event-free survival of 73 +/- 19%. In conclusion, intensive multiagent chemotherapy offers an attractive therapeutic option for children and adolescents with Ph+ ALL and low presenting leukocyte count.

Ewing's sarcoma of soft tissues in childhood: a report from the Intergroup Rhabdomyosarcoma Study, 1972 to 1991

PURPOSE

One hundred thirty of 2,792 patients (5%) registered on three Intergroup Rhabdomyosarcoma Study clinical trials (IRS-I, -II, and -III) from 1972 to 1991 had an extraosseous Ewing's sarcoma (EOE). We report here the results of multimodality therapy for this tumor.

PATIENTS AND METHODS

The 130 patients were less than 21 years of age; 70 (54%) were males. Primary tumor sites were on the trunk in 41 patients, an extremity in 34, the head/neck in 23, the retroperitoneum/pelvis in 21, and other sites in 11. One hundred fourteen patients had no metastases at diagnosis. In 21 patients, the tumor was completely resected; in 30, the localized or regional tumor was grossly resected, and in 63 patients, grossly visible sarcoma was left behind. Sixteen patients (12%) had distant metastases at diagnosis. All patients were given multiagent chemotherapy and most received irradiation (XRT); none were treated with bone marrow transplantation.

RESULTS

One hundred seven patients (82%) achieved a complete response. At 10 years, 62%, 61%, and 77% of the patients were alive after treatment on IRS-I, IRS-II, or IRS-III therapeutic protocols, respectively, similar to figures obtained in all IRS patients. At last follow-up evaluation, 42 patients had died of progressive tumor and one of infection. Survival at 10 years was most likely for patients with tumor that arose in the head and neck, extremities, and trunk, and for those who underwent grossly complete tumor removal before initiation of chemotherapy. For patients with localized, gross residual tumor, adding doxorubicin (DOX) to the combination of vincristine, dactinomycin, cyclophosphamide (VAC), and XRT did not significantly improve survival in 39 patients (62% alive at 10 years) compared with that of 24 patients treated with VAC and XRT without DOX (65% alive at 10 years, P = .93).

CONCLUSION

This series indicated that EOE in children is similar to rhabdomyosarcoma (RMS) in its response to multimodal treatment. No benefit was apparent from the addition of DOX to VAC chemotherapy in patients with gross residual EOE.

Uniform approach to risk classification and treatment assignment for children with acute lymphoblastic leukemia

PURPOSE

To define more uniform criteria for risk-based treatment assignment for children with acute lymphoblastic leukemia (ALL), the Cancer Therapy Evaluation Program (CTEP) of the National Cancer Institute (NCI) sponsored a workshop in September 1993. Participants included representatives from the Childrens Cancer Group (CCG), Pediatric Oncology Group (POG), Dana-Farber Cancer Institute (DFCI), St Jude Children's Research Hospital (SJCRH), and the CTEP.

METHODS

Workshop participants presented and reviewed data from ALL clinical trials, using weighted averages to combine outcome data from different groups.

RESULTS

For patients with B-precursor (ie, non-T, non-B) ALL, the standard-risk category (4-year event-free survival [EFS] rate, approximately 80%) will include patients 1 to 9 years of age with a WBC count at diagnosis less than 50,000/microL. The remaining patients will be classified as having high-risk ALL (4-year EFS rate, approximately 65%). For patients with T-cell ALL, different treatment strategies have yielded different conclusions concerning the prognostic significance of T-cell immunophenotype. Therefore, some groups/institutions will classify patients with T-cell ALL as high risk, while others will assign risk for patients with T-cell ALL based on the uniform age/WBC count criteria. Workshop participants agreed that the risk category of a patient may be modified by prognostic factors in addition to age and WBC count criteria, and that a common set of prognostic factors should be uniformly obtained, including DNA index (DI), cytogenetics, early response to treatment (eg, day-14 bone marrow), immunophenotype, and CNS status.

CONCLUSIONS

The more uniform approach to risk-based treatment assignment and to collection of specific prognostic factors should increase the efficiency of future ALL clinical research.

The Third Intergroup Rhabdomyosarcoma Study

PURPOSE

The ultimate goal of the Third Intergroup Rhabdomyosarcoma Study (IRS-III, 1984 to 1991) was to improve treatment outcome in children with rhabdomyosarcoma through clinical trials comparing risk-based protocols of surgery and multiagent chemotherapy, with or without irradiation.

PATIENTS AND METHODS

One thousand sixty-two previously untreated, eligible patients who were entered onto the study after surgery were randomized or assigned to treatment by clinical group (I through IV), histology (unfavorable or favorable), and site of the primary tumor. Initial responses, progression-free survival (PFS), and survival (S) were the end points used in comparisons between randomized groups and between patients treated in IRS-III and IRS-II (1978 to 1984).

RESULTS

The overall outcome of therapy in IRS-III was significantly better than in IRS-II (5-year PFS, 65% +/- 2% v 55% +/- 2%; P < .001 by stratified testing). Patients with group I favorable-histology tumors fared as well on a 1-year regimen of vincristine and dactinomycin (VA), as did a comparable group treated with VA plus cyclophosphamide (C) (5-year PFS, 83% +/- 3% v 76% +/- 4%; P = .18). Results for patients with group II favorable-histology tumors, excluding orbit, head, and paratesticular sites, were inconclusive regarding the benefit from addition of doxorubicin (ADR) to VA. Patients with group III tumors, excluding those in special pelvic, orbit, and other selected nonparameningeal head sites, fared much better on the more intensive regimens of IRS-III than on pulsed VAC or VAC-VADRC in IRS-II (5-year PFS estimates, 62% +/- 3% v 52% +/- 3%; P < .01); however, there were no significant differences in outcome among the groups treated in IRS-III. Patients with metastatic disease at diagnosis (clinical group IV) did not benefit significantly from the more complex therapies evaluated in IRS-III.

CONCLUSION

Intensification of therapy for most patients in IRS-III, using a risk-based study design, significantly improved treatment outcome overall. The largest gain from this strategy was realized in patients with gross residual tumor after biopsy (clinical group III). It was also possible to decrease therapy for selected patient subsets without compromising survival.

Phase I study of oral etoposide in children with refractory solid tumors

PURPOSE

To determine the maximum-tolerated dose (MTD), dose-limiting toxicity, and plasma concentrations of orally administered etoposide (VP-16) in pediatric oncology patients.

PATIENTS AND METHODS

In a phase I study, 20 children with refractory solid tumors received oral VP-16 (the intravenous preparation diluted with sodium chloride) three times daily for 21 days. Daily dose levels studied were 50 mg/m2 (n = 5), 60 mg/m2 (n = 7), and 75 mg/m2 (n = 8). VP-16 concentrations were measured in blood samples collected on days 1, 7, 14, and 21.

RESULTS

Grade 3 to 4 thrombocytopenia and/or neutropenia causing interruption of the 21-day course or persisting for more than 7 days after the last day of chemotherapy was seen at all dose levels, but was not dose-limiting. One patient treated at the 50-mg/m2 daily dose died of sepsis. At the 75-mg/m2 dose level, diarrhea was dose-limiting. Estimated plasma VP-16 concentrations were greater than 1 micrograms/mL for median periods of 9.4, 15.4, and 13.5 hours per day at daily doses of 50, 60, and 75 mg/m2, respectively. Responses were observed in seven of 14 patients who received at least one additional course of etoposide after a rest period of 7 days. There was one complete and two objective responses. Four patients were considered to have stable disease.

CONCLUSION

The intravenous preparation of VP-16 administered orally appears to be well tolerated by heavily pretreated pediatric patients. On the three-times daily, 21-day schedule, a daily dose of 75 mg/m2 exceeds the MTD, with diarrhea as the dose-limiting toxicity. The recommended dose for oral etoposide is 60 mg/m2/d administered every 8 hours.

Retroperitoneal node biopsy in paratesticular rhabdomyosarcoma

Retroperitoneal lymph node dissection (RPLND) was used in 121 Intergroup Rhabdomyosarcoma Study (IRS) III patients with nonmetastatic paratesticular (PT) rhabdomyosarcoma (RMS) to assess retroperitoneal lymph node (RPLN) involvement so as to determine the need for x-ray therapy (XRT). Clinical node evaluation (CNE) was accomplished by a computed tomography (CT) scan in 105 and a sonogram in six. Pathological node evaluation (PNE) was performed in 113: lymphadenectomy (9 bilateral, 85 unilateral) and biopsy in 19. Vincristine and actinomycin D were used for 1 year postoperatively in 89%; all patients who had positive PNE received RPLN XRT. This study compares CNE with PNE and evaluates predictors of relapse and survival.

FINDINGS

There were clinically negative nodes (cN0) in 81% of the 121 patients. Among cN0 patients, 14% had positive nodes (pN1). Of the clinically positive (cN1) patients, 94% had pN1. RPLN relapse occurred in only two of the 121 patients. Initially both had cN0 and one had PNE that was negative. For all 121 patients, the 5-year survival was 91%. For cN0 patients, the 5-year survival was 96% compared with 69% for cN1 patients (P < .001). Among the children in whom treatment failed, nodes were cN1 in 5 of 11 (45%) compared with 15 of 107 (14%) in those whose treatment did not fail (P < .008).

CONCLUSIONS

(1) Results of RPLN imaging studies were negative in 81% of patients with PT RMS (specificity 99%, sensitivity 57%). (2) RPLN recurrence is uncommon (even when RPLN are initially involved) if regional XRT and appropriate chemotherapy are used.(ABSTRACT TRUNCATED AT 250 WORDS)

Transitional pre-B-cell acute lymphoblastic leukemia of childhood is associated with favorable prognostic clinical features and an excellent outcome: a Pediatric Oncology Group study

The presenting characteristics and survival of children with the newly recognized transitional cell pre-B immunophenotype of acute lymphoblastic leukemia (ALL) are compared with those of children with pre-B ALL to determine the clinical significance of the new phenotype. Patients with transitional pre-B ALL (n = 17), defined by lymphoblasts expressing cytoplasmic and surface mu heavy chains without kappa or lambda light chains, have lower initial leukocyte counts (p = 0.02) and a higher frequency of DNA indexes > 1.16 (p < 0.001) than patients with pre-B ALL (n = 501), whether or not cases with the unfavorable prognostic (1;19) translocation are included in the analysis. Patients with transitional pre-B ALL lack FAB L3 morphology, bulky extramedullary disease, surface kappa or lambda chains, and the (8;14), (8;22), and (2;8) translocations, features that characterize the syndrome of B-cell ALL. The 4-year relapse-free survival result for children with transitional pre-B ALL appears better than that for children with pre-B ALL (93.3 +/- 17% versus 72.9% +/- 4.6%), but this difference is not statistically significant. We conclude that patients with transitional pre-B ALL have a very favorable prognosis in the context of the therapy used in this study.

Extended triple intrathecal chemotherapy trial for prevention of CNS relapse in good-risk and poor-risk patients with B-progenitor acute lymphoblastic leukemia: a Pediatric Oncology Group study

PURPOSE

The Pediatric Oncology Group (POG) acute leukemia in childhood (ALinC) 13 study tested two treatment regimens that used different CNS chemoprophylaxis for children older than 12 months with non-T, non-B acute lymphoblastic leukemia (ALL) and with no demonstrable CNS disease at diagnosis.

PATIENTS AND METHODS

With the first regimen, standard (S), six injections of triple intrathecal chemotherapy (TIC), consisting of methotrexate (MTX), hydrocortisone (HC), and cytarabine (ara-C), were administered during intensification treatment and at every-8-week intervals throughout the maintenance phase for 17 additional doses. The second regimen, standard and MTX pulses (SAM), also specified six TICs during intensification, but substituted every-8-week pulses of intermediate-dose parenteral methotrexate (IDM; 1 g/m2) for the 17 maintenance TIC injections, with a low-dose intrathecal (IT) MTX boost administered with the first four maintenance IDM pulses. Otherwise, systemic therapy on regimen SAM was identical to regimen S. There were 1,152 patients randomized to the S and SAM regimens after stratification by risk group (age/leukocyte count) and immunophenotype.

RESULTS

The 5-year probabilities (+/- SE) of an isolated CNS relapse were regimen S: good risk (n = 381), 2.8% +/- 1.3%; poor risk (n = 196), 7.7% +/- 3.2%; good + poor risk (n = 577), 4.7% +/- 1.5%; regimen SAM: good risk (n = 388), 9.6% +/- 2.2%; poor risk (n = 187), 12.7% +/- 4.2%; good + poor risk (n = 575), 10.9% +/- 2.2%. In poor-risk patients, approximately one third of the isolated CNS relapses occurred before preventive CNS therapy was begun at week 9. Hence, regimen S has provided better CNS preventive therapy for both good- and poor-risk patients (P < .001 overall). The difference is statistically significant for good-risk patients (P < .001), but not for poor-risk patients (P = .20). Neither treatment has shown a significant advantage in terms of general outcome.

CONCLUSION

TIC injections extended throughout the intensification and maintenance periods are superior to IDM pulses for prevention of CNS leukemia. Our results with TIC seem comparable with those achieved with other contemporary methods of CNS preventative therapy. Thus, extended TIC affords a reasonable alternative to CNS irradiation plus upfront IT MTX for patients with B-progenitor ALL.

The Intergroup Rhabdomyosarcoma Study-II

BACKGROUND

Intergroup Rhabdomyosarcoma Study (IRS)-II, (1978-1984) had the general goals of improving the survival and treatment of children with rhabdomyosarcoma (RMS).

METHODS

Nine hundred ninety-nine previously untreated eligible patients entered the study after surgery and were randomized or assigned to therapy by IRS Clinical Group (I-IV), tumor site, and histologic type. Outcomes were compared between treatments and with results of IRS-I (1972-1978).

RESULTS

Patients in Group I, excluding extremity alveolar (EA) RMS, were randomized to standard vincristine (V), dactinomycin (A), and cyclophosphamide (C) or standard VA. At 5 years, disease-free survival (DFS) and survival (S) rates were similar between VAC and VA (DFS: 80%, 70%, P = 0.47; S: 85%, 84%, P = 0.73). Patients in Group II, excluding EA RMS, received radiation and were randomized to intensive VA or repetitive-pulse VAC. Outcomes were similar for rates of DFS (69%, 74%, P = 0.83) and S (88%, 79%, P = 0.17). Patients in Group III, excluding certain pelvic tumors, received radiation and were randomized to repetitive-pulse VAC or repetitive-pulse VAdrC-VAC (Adr, Adriamycin [doxorubicin]). Complete remission (CR) rates were close at 74%, 78%, respectively (P = 0.32), as were percentages in CR (73%) and S (66%) rates; the latter outcomes were significantly better than IRS-I (CR: 56%, P < 0.001; S: 50%, P < 0.001). Central nervous system prophylaxis for Group III patients with cranial parameningeal sarcoma increased S rate to 67% from 45% in IRS-I (P < 0.001). Patients in Group IV received the same regimens as Group III; the CR rate was 53%, 38% remained in CR and S rate was 27% with and 26% without Adr (P = 0.90). At 5 years, S rate for IRS-II, including EA and all pelvic tumors, was 63%: an 8% increase over IRS-I (P < 0.001). Outcomes by primary site were as good as, or better than, the IRS-I experience.

CONCLUSIONS

Combining all Groups and treatments in IRS-II, the major improvement in S rate at 5 years between studies was in nonmetastatic patients (71% for IRS-II versus 63% for IRS-I, P = 0.01).

The Intergroup Rhabdomyosarcoma Study-II

BACKGROUND

Intergroup Rhabdomyosarcoma Study (IRS)-II, (1978-1984) had the general goals of improving the survival and treatment of children with rhabdomyosarcoma (RMS).

METHODS

Nine hundred ninety-nine previously untreated eligible patients entered the study after surgery and were randomized or assigned to therapy by IRS Clinical Group (I-IV), tumor site, and histologic type. Outcomes were compared between treatments and with results of IRS-I (1972-1978).

RESULTS

Patients in Group I, excluding extremity alveolar (EA) RMS, were randomized to standard vincristine (V), dactinomycin (A), and cyclophosphamide (C) or standard VA. At 5 years, disease-free survival (DFS) and survival (S) rates were similar between VAC and VA (DFS: 80%, 70%, P = 0.47; S: 85%, 84%, P = 0.73). Patients in Group II, excluding EA RMS, received radiation and were randomized to intensive VA or repetitive-pulse VAC. Outcomes were similar for rates of DFS (69%, 74%, P = 0.83) and S (88%, 79%, P = 0.17). Patients in Group III, excluding certain pelvic tumors, received radiation and were randomized to repetitive-pulse VAC or repetitive-pulse VAdrC-VAC (Adr, Adriamycin [doxorubicin]). Complete remission (CR) rates were close at 74%, 78%, respectively (P = 0.32), as were percentages in CR (73%) and S (66%) rates; the latter outcomes were significantly better than IRS-I (CR: 56%, P < 0.001; S: 50%, P < 0.001). Central nervous system prophylaxis for Group III patients with cranial parameningeal sarcoma increased S rate to 67% from 45% in IRS-I (P < 0.001). Patients in Group IV received the same regimens as Group III; the CR rate was 53%, 38% remained in CR and S rate was 27% with and 26% without Adr (P = 0.90). At 5 years, S rate for IRS-II, including EA and all pelvic tumors, was 63%: an 8% increase over IRS-I (P < 0.001). Outcomes by primary site were as good as, or better than, the IRS-I experience.

CONCLUSIONS

Combining all Groups and treatments in IRS-II, the major improvement in S rate at 5 years between studies was in nonmetastatic patients (71% for IRS-II versus 63% for IRS-I, P = 0.01).

G19.4(alpha CD3) x B43(alpha CD19) monoclonal antibody heteroconjugate triggers CD19 antigen-specific lysis of t(4;11) acute lymphoblastic leukemia cells by activated CD3 antigen-positive cytotoxic T cells

A highly purified, 300-Kd bispecific monoclonal antibody (MoAb) heteroconjugate was prepared by covalently linking the anti-CD3 MoAb, G19.4, to the anti-CD19 MoAb, B43. Dual-color staining techniques and multiparameter flow cytometry confirmed that this alpha CD3 x alpha CD19 heteroconjugate was able to bind to both CD3+ T cells and CD19+ t(4;11) acute lymphoblastic leukemia (ALL) cells. T-cell-mediated lysis of freshly isolated primary bone marrow blasts from nine newly diagnosed ALL patients with a t(4;11)(q21;q23) chromosomal translocation were studied with 51Cr-release assays. Picomolar concentrations of alpha CD3 x alpha CD19 MoAb heteroconjugate effectively triggered lysis of CD19+ t(4;11) ALL cells by interleukin-2-activated CD3+ peripheral blood T-cell (PBTC) effectors but did not augment the cytolytic activity of the same effectors against CD19- T-ALL cells. In contrast to the alpha CD3 x alpha CD19 heteroconjugate, neither the alpha CD3 x alpha CD3 homoconjugate control nor the alpha CD19 x alpha CD72 heteroconjugate control facilitated the cytolysis of t(4;11) ALL blasts. Occupation of the target CD19 binding sites on t(4;11) ALL blasts by preincubation with excess unconjugated alpha CD19 MoAb abrogated the potentiating effects of the alpha CD3 x alpha CD19 heteroconjugate on PBTC-mediated cytolysis. Thus, the cell type-specific cytolysis of t(4;11) ALL blasts by PBTC effectors is dependent on both the alpha CD19 and alpha CD3 moieties of the alpha CD3 x alpha CD19 heteroconjugate. To our knowledge, this is the first description of an effective bispecific antibody that facilitates the T-cell-mediated lysis of t(4;11) ALL blasts.

The non-random dic(9;12) translocation in acute lymphoblastic leukemia is associated with B-progenitor phenotype and an excellent prognosis

A dicentric translocation involving the short arms (p) of chromosomes 9 and 12 was identified in 15 of 2303 successfully banded cases of acute lymphoblastic leukemia (ALL) in children, consecutively entered on protocols of the Pediatric Oncology Group (1986-1990) or St Jude Children's Research Hospital (1984 and 1990). The dic(9;12)(p1?1;p1?2) was seen only in patients with a B progenitor cell immunophenotype: the frequency was 0.8% among pre-B cases (4/508) and 0.9% (11/1177) among early pre-B cases. Laboratory and clinical characteristics were similar to those of the general population of children with ALL, with the exception of a marked male preponderance (12/15 cases). Flow cytometric studies revealed a leukemic cell DNA index of 1.0 in all cases. All fifteen patients are in continuous complete remission at a median follow-up duration of 57+ months (range 9-93+ months). These findings suggest that the dic(9;12) is a recurrent chromosomal translocation in pediatric ALL, occurs exclusively in B-progenitor ALL, and unlike other non-random translocations, is associated with an excellent prognosis.

Ploidy of lymphoblasts is the strongest predictor of treatment outcome in B-progenitor cell acute lymphoblastic leukemia of childhood: a Pediatric Oncology Group study

PURPOSE

Using the technique of recursive partitioning and amalgamation analysis with verification, the Pediatric Oncology Group (POG) investigated the independent prognostic significance of previously published prognostic factors significantly associated with event-free survival (EFS) in B-progenitor cell acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Age, leukocyte count, sex, immunophenotype (expression of cytoplasmic immunoglobulin [Ig] and of surface antigens CD10 and CD34), and DNA index (ratio of the flow cytometry-determined DNA content of leukemia cells to that of normal diploid cells) were the variables used in the evaluation of four antimetabolite-based chemotherapy regimens in 1,535 children with the newly diagnosed B-progenitor cell ALL between February 1986 and May 1990.

RESULTS

There were three subgroups at widely different risks of treatment failure. A DNA index greater than 1.16 was the most prognostic feature. The final prognostic subgrouping was as follows: (1) DNA index greater than 1.16; (2) DNA index less than or equal to 1.16, age less than 11.0 years, and leukocyte count less than 50 x 10(9)/L; and (3) DNA index less than or equal to 1.16, (age greater than 11.0 years, and/or leukocyte count greater than 50 x 10(9)/L). These groups made up 20%, 53%, and 27% of the patients and had 4-year EFS rates (SE) of 90.1% (6.3%), 80.5% (5.1%), and 50.4% (7.6%), respectively.

CONCLUSIONS

Use of the DNA index, leukocyte count, and age--data that are relatively inexpensive and simple to obtain--may be sufficient to stratify patients with B-progenitor cell ALL for risk-directed therapy. Patients at an extremely low risk of failing therapy (approximately 20% of cases in this study) can thus be identified and spared the toxic short-term and late effects of more intensive therapies that may be needed for children with less favorable clinical and biologic features.

Clinical features and results of therapy for children with paraspinal soft tissue sarcoma: a report of the Intergroup Rhabdomyosarcoma Study

Soft tissue sarcomas of the paraspinal region comprised 3.3% (56 of 1,688) of the patients entered and eligible on Intergroup Rhabdomyosarcoma Studies I (IRS-I) and II (IRS-II) (1972 to 1984). These lesions tended to be greater than 5 cm in diameter at diagnosis, invaded the spinal extradural space, and were of the extraosseous Ewing's sarcoma or undifferentiated sarcoma subtype in 55% (30 of 56) of the cases. Patients with tumors in clinical groups II, III, and IV were treated with radiotherapy (XRT) and vincristine-dactinomycin (VA) or VA plus cyclophosphamide (VAC) +/- doxorubicin. Clinical group I patients treated on IRS-II did not receive XRT, while those on IRS-I were randomized to receive VAC +/- XRT. Forty-four of the paraspinal patients (79%) achieved a complete response (CR) compared with 77% (1,260 of 1,632) for patients with disease in other sites. Twenty-seven patients (55%) subsequently relapsed (five local, three regional, four local and distant, and 14 distant). The proportion of patients surviving 5 years by clinical group (stage) from I to IV were 50%, 50%, 62%, and 27%, respectively. Paraspinal patients had somewhat poorer survival than patients with disease in other sites, both in IRS-I and IRS-II; the percentage of paraspinal patients surviving 5 years was 50% and 52% for IRS-I and IRS-II, respectively, whereas these percentages were 55% and 63% for patients with disease in other sites. Histology did not influence the CR rate, but unexpectedly, patients who had embryonal rhabdomyosarcoma (RMS) had the poorest overall survival rate. We concluded that patients with paraspinal lesions may require extended-field radiation therapy to reduce the high local failure rate and more intensive chemotherapy to achieve better local and systemic tumor control.

Philadelphia chromosome and monosomy 7 in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

During an 8-year period, 3,638 children from institutions of the Pediatric Oncology Group (POG) were diagnosed with acute lymphoblastic leukemia (ALL). Fifty-seven patients had Philadelphia chromosome-positive (Ph1) ALL. Blast cells obtained at diagnosis from 13 of these 57 cases (23%) were also found to have partial or complete monosomy 7 (-7). This subgroup of children with Ph1/-7 ALL was comprised primarily of older males with early B-lineage ALL. Bone marrow specimens from six Ph1/-7 patients were studied further using the polymerase chain reaction and primers that flank the ALL, and chronic myelogenous leukemia breakpoints to determine the molecular characteristic of the 9;22 translocation. Rearrangements were detected in RNA from bone marrow and/or peripheral blood cells of six patients, although four were in hematologic remission at the time of the analysis. Five cases showed the ALL breakpoint, while one child with Ph1/-7 showed the chronic myelogenous leukemia breakpoint. The induction failure rate was much higher in this subgroup (31%) as compared with Ph1-negative cases, and the projected duration of event-free survival reflected the aggressive nature of this subgroup because no children are projected to remain in remission at 2 years. ALL with both the 9;22 translocation and -7 appears to represent a unique and previously undescribed subgroup of childhood ALL associated with a particularly adverse outcome. Leukemic transformation in such patients may involve the interaction of a dominant oncogene (Ph1) and a tumor suppressor gene (-7).

A pilot study of intermediate-dose methotrexate and cytosine arabinoside, "spread-out" or "up-front," in continuation therapy for childhood non-T, non-B acute lymphoblastic leukemia. A Pediatric Oncology Group study

One hundred six children with newly diagnosed non-T-, non-B-cell acute lymphoblastic leukemia (ALL) were treated in a Pediatric Oncology Group (POG) pilot study in which six courses of intermediate-dose methotrexate (MTX) and cytosine arabinoside (Ara-C) (1 g/m2 each) were added to a "backbone" of standard continuation therapy. The dose and sequence of MTX/Ara-C administration were based on a preclinical model that demonstrated synergism between MTX and Ara-C. Poor-risk patients (n = 49) were assigned to "up-front" therapy, in which the MTX/Ara-C courses were administered during the initial 15 weeks of remission. Standard-risk patients (n = 57) were assigned to "spread-out" therapy, in which the MTX/Ara-C courses were interspersed at 12-week intervals within continuation treatment. Toxicity after intermediate-dose MTX/Ara-C, principally neutropenia and fever, was judged significant but manageable. Unexpectedly, the incidence of fever and neutropenia less than 500/mm3 was greater after "spread-out" therapy (38%) than after "up-front" therapy (6%). At 4 years, the Kaplan-Meier estimate of event-free survival (EFS) is 71% (+/- 7%) for standard-risk patients and 53% (+/- 8%) for poor-risk patients. The results of this pilot study support the use of intermediate-dose MTX/Ara-C in additional studies.

Consistent involvement of the bcr gene by 9;22 breakpoints in pediatric acute leukemias

To investigate the relationship of bcr-abl fusion mRNAs with childhood acute lymphoblastic leukemias (ALL), we examined 27 pediatric Philadelphia chromosome (Ph1)-positive acute leukemias using a reverse polymerase chain reaction (PCR) procedure. In cells from 24 leukemias, single bcr-abl PCR products were detected that corresponded to breakpoints in the minor breakpoint cluster region (mbcr in intron 1 of the bcr gene) associated with production of the P190 fusion protein. Cells from the three remaining leukemias contained breakpoints in the major breakpoint cluster region (Mbcr) as shown by PCR and Southern blot analyses. These three leukemias also contained low levels of the mbcr PCR product that may have resulted from alternative splicing of the bcr-abl precursor RNA. A screen of 35 additional leukemias from patients who failed therapy before day 180 (induction failures or early relapses) found one case with unsuccessful cytogenetics to express Mbcr-abl RNA. All four children with Mbcr breakpoints had white blood cell levels in excess of 250,000 at presentation (compared with 2 of 24 with mbcr breakpoints) and two had hematologic and clinical features suggestive of chronic myelogenous leukemias (CML) in lymphoid blast crisis. Our results indicate that in Ph1-positive pediatric leukemias, all 9;22 breakpoints occur in one of the two known breakpoint cluster regions in the bcr gene on chromosome 22. The reverse PCR reliably detected all patients with cytogenetic t(9;22) and is capable of detecting additional Ph1-positive leukemias that are missed by standard cytogenetics. Furthermore, the Mbcr-type breakpoint, associated with production of p210, can be seen in childhood leukemias presenting either as clinical ALL or as apparent lymphoid blast crisis of CML, suggesting that t(9;22) breakpoint locations do not exclusively determine the biologic and clinical features of pediatric Ph1-positive ALL.

High-dose cyclophosphamide-high-dose methotrexate with coordinated intrathecal therapy for advanced nonlymphoblastic lymphoma of childhood: results of a Pediatric Oncology Group study

The Pediatric Oncology Group (POG) investigated a high-dose cyclophosphamide (CPM) high-dose methotrexate (MTX) regimen to determine therapeutic efficacy in confirmed advanced nonlymphoblastic non-Hodgkin's lymphoma (NHL) (stages III and IV) and B-cell acute lymphatic leukemia (B-ALL) in children. Another goal was to determine the comparative effectiveness of shortened maintenance treatment (2 versus 6 courses) in the study population. Systemic induction therapy included vincristine, prednisone, cyclophosphamide, and intermediate-dose MTX with leucovorin rescue. Superimposed intrathecal (IT) therapy included cytosine arabinoside for 2 successive days followed on day 3 by MTX. Intrathecal MTX was given 3 times during induction. At the end of induction, 2 days of triple (hydrocortisone, MTX, and cytosine arabinoside) therapy were given intrathecally (TIT). All patients then received a consolidation course of 4 doses of TIT, 2 doses of cyclophosphamide, and 4 more courses of vincristine and MTX with leucovorin rescue. Patients were then randomized to receive either 2 or 6 cycles of vincristine plus MTX with leucovorin rescue. The TIT was given with each cycle. Complete response rates by histology and Murphy stage (1) were as follows: undifferentiated lymphoma (DUL) stage III, 84/105 (80%): stage IV, 5/12 (42%); and other NHL [primarily large cell lymphoma (LCL)] stage III, 21/28 (75%); stage IV, 2/3 (67%). Event-free survival (EFS) at greater than 2 years was similar for patients with DUL and LCL, i.e., 65 and 61%, respectively. No significant difference in outcome was noted between patient groups receiving 2 or 6 maintenance treatments (p = .76). Treatment was notable for its modest toxicity following the early change to single-dose CPM therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Down-regulated c-myb expression inhibits DNA synthesis of T-leukemia cells in most patients

We have investigated the functional relevance of c-myb expression for DNA synthesis in patients' T-leukemia cells. [3H]Thymidine incorporation assays of 32 patients' leukemia cells exposed in vitro to c-myb sense or antisense oligodeoxynucleotides served to define two groups of patients: a responder group whose leukemia cells showed 2- to 16-fold lower levels of [3H]thymidine incorporation in c-myb antisense-treated cultures than in c-myb sense-treated cultures (20 patients) and a nonresponder group whose cells showed comparable [3H]thymidine incorporation levels in either c-myb sense- or antisense-treated cultures (12 patients). Down-regulation of c-myb mRNA levels in cells exposed to c-myb antisense oligodeoxynucleotides was comparable in both groups of patients, indicating that differential sensitivity to c-myb antisense oligodeoxynucleotides was not due to differential uptake of these oligodeoxynucleotides. DNA polymerase alpha mRNA levels were down-regulated in cells from the responders but were unaffected in the nonresponder group. These results suggest that c-myb is required for DNA synthesis in cells of many but not all T-leukemia patients and that leukemia cells in which DNA synthesis is not inhibited despite down-regulation of c-myb expression may have undergone some genetic change(s) that obviate(s) the requirement for myb protein.

Teniposide (VM-26) and continuous infusion cytosine arabinoside for initial induction failure in childhood acute lymphoblastic leukemia. A Pediatric Oncology Group pilot study

Twenty-six evaluable children with newly diagnosed acute lymphoblastic leukemia (ALL) who failed to achieve initial remission after receiving two to seven drugs for at least a 4-week period were given teniposide (VM-26) and continuous infusion cytosine arabinoside (Ara-C). Twenty-two received 150 mg/m2 of VM-26 on days 1 and 2 with 100 mg/2 of Ara-C as a continuous infusion on days 1 through 5; a second shortened course was given on day 14 to eight patients who had evidence of some antileukemic effect or were clinically judged able to tolerate a second course. The last four patients received three daily doses of VM-26 and a 7-day infusion of Ara-C at the same daily dosages. Twelve (48%) achieved complete remission (CR) of ALL. There was a trend toward decreasing response rates with an increasing number of drugs used in the initial induction regimen, i.e., five CR among seven patients with a prior two-drug induction attempt, six CR among 14 patients with a prior three- to four-drug induction attempt, and one CR among four patients with a prior five- to seven-drug induction attempt (P = 0.14). Ten of 17 non-T-cell patients and two of nine T-cell patients achieved remission (P = 0.10). The median time required to achieve a complete remission from the initiation of treatment was 26 days (range, 14-72 days). This period was shorter in those who required one course compared with those who required two induction courses, i.e., 25 days median vs. 44 days median. Toxicity was significant and due mainly to marrow aplasia and infection; one patient had severe prolonged VM-26-induced hypotension. Of the 12 patients entering remission, two were removed for marrow transplant and one was removed due to parental request. In the remaining nine patients, median remission duration was only 2 months (range, 1-18 months). All nine patients relapsed in the marrow. Among the entire group of 26 patients, only one patient is alive and a long-term event-free survivor (after allogeneic marrow transplant). Due to the current use of more aggressive initial induction regimens and the extremely poor prognosis in children who fail to achieve initial remission, more intensive regimens of continuation therapy or alternative therapies, such as bone marrow transplant, should be considered.

Site-specific recombination of the tal-1 gene is a common occurrence in human T cell leukemia

The tal-1 gene is altered as a consequence of the t(1;14) (p32;q11) chromosome translocation observed in 3% of patients with T cell acute lymphoblastic leukemia (T-ALL). tal-1 encodes a helix-loop-helix (HLH) domain, a DNA binding and dimerization motif found in a number of proteins involved in cell growth and differentiation. We now report that an additional 25% of T-ALL patients bear tal-1 gene rearrangements that are not detected by karyotype analysis. These rearrangements result from a precise 90 kb deletion (designated tald) that arises independently in different patients by site-specific DNA recombination. Since the deletion junctions resemble the coding joints of assembled immunoglobulin genes, tald rearrangements are likely to be mediated by aberrant activity of the immunoglobulin recombinase. Moreover, t(1;14)(p32;q11) translocations and tald rearrangements disrupt the coding potential of tal-1 in an equivalent manner, and thereby generate a common genetic lesion shared by a significant proportion of T-ALL patients.

Favorable prognosis associated with hyperdiploidy in children with acute lymphocytic leukemia correlates with extra chromosome 6. A Pediatric Oncology Group study

Pretreatment bone marrow cytogenetic studies were included for 1664 patients with acute lymphoblastic leukemia (ALL) accrued to Pediatric Oncology Group (POG) 8035 laboratory classification study from May 1981 through January 1986. There was a significant difference (P = 0.0001) in distribution of stem-line karyotype (normal, hypodiploid, pseudodiploid, or hyperdiploid) among children with early pre-B, pre-B, or T-cell ALL, with early pre-B patients demonstrating a higher proportion of hyperdiploid karyotypes with modal chromosome numbers greater than 51. Cytogenetic classification of 1216 patients with early pre-B or pre-B ALL evaluable for duration of event-free survival (EFS), with median follow-up of 42 months, showed a significant prolongation of five-year EFS associated with hyperdiploidy greater than 51 (75%; standard error [SE] = 5%) compared with hyperdiploidy 47 to 51 (46%; SE = 7%), hypodiploidy (55%; SE = 11%), and pseudodiploidy (45%; SE = 7%) (P = 0.0001). Five-year EFS was intermediate for patients with normal (58%), constitutionally abnormal (66%), or unsuccessful analyses (66%). The breakpoint defining hyperdiploidy associated with better prognosis was best defined as greater than 51 (P = 0.0002). Of 239 children with hyperdiploid karyotypes, analysis of the contribution of each chromosome to EFS duration showed a significant association between improved EFS and additional chromosome(s) six (P = 0.02). Chromosome translocation was associated with shorter EFS (P = 0.0001).

Philadelphia chromosome positive childhood acute lymphoblastic leukemia: clinical and cytogenetic characteristics and treatment outcome. A Pediatric Oncology Group study

Among 3,638 children with acute lymphoblastic leukemia (ALL) entered on Pediatric Oncology Group (POG) protocols between June 1981 and April 1989, successful cytogenetic studies were available for 2,519, 58 (2.3%) of which had the Philadelphia (Ph) chromosome detected. Features associated with the presence of the Ph chromosome were high leukocyte count (median, 33 x 10(9)/L), older age median, 9.6 years), a higher proportion of French-American-British L2 morphology, and a lower frequency of mediastinal mass. Immunologic marker studies at diagnosis in 56 Ph+ cases identified early pre-B ALL in 42 cases (75%), pre-B-cell in 9 (16%), and T-cell in 5 (9%). This distribution is similar to that found in Ph+ ALL. Intensive multiagent chemotherapy induced complete remissions in only 78% of eligible Ph+ patients compared with 96% of those without an identified Ph chromosome (P less than .001). Of 44 eligible Ph+ patients treated on POG frontline protocols for children with non-T, non-B-cell ALL, 27 have failed therapy, compared with 520 of 1,892 without an identified Ph chromosome (logrank P less than .001). Ph+ ALL is an aggressive form of acute leukemia that frequently presents in older children with a high leukocyte count, FAB L2 morphology, and a pseudodiploid karyotype, and becomes multidrug-resistant early. Thus, Ph+ cases require early identification to permit treatment with intensive induction regimens and experimental approaches such as bone marrow transplantation.

Soft tissue sarcoma of the perineal region in childhood. A report from the Intergroup Rhabdomyosarcoma Studies I and II, 1972 through 1984

Thirty-six previously untreated patients younger than 21 years of age with sarcoma arising in the perineal region were entered on the Intergroup Rhabdomyosarcoma Studies (IRS) I and II from 1972 through 1984. The tumor histologic subtype was alveolar rhabdomyosarcoma (RMS) in 20 patients (56%), embryonal RMS in 11 patients (30%), and other types of sarcoma in 5 patients (14%). Fifteen children had grossly complete surgical excision (Clinical Groups I and II), and 15 had localized gross residual tumor (Group III) after initial operative management. Six patients had distant metastases (Group IV) at diagnosis. Twelve patients without distant metastases underwent regional lymph node biopsy; tumor involvement was found in six. Subsequent treatment consisted of chemotherapy with vincristine (VCR) and dactinomycin (AMD) for all patients; patients in Groups III and IV also received cyclophosphamide (CYC) with or without Adriamycin (ADR) (doxorubicin; Adria Laboratories, Columbus, OH). Radiation therapy (RT) was administered to patients in Clinical Groups II, III, and IV. Overall, 28 (78%) patients achieved a complete clinical response. The 3-year disease-free survival rate for these patients was 42%, compared with 52% for all other patients in the combined IRS I and IRS II series (P = 0.44). The overall 3-year survival rate was 59%, compared with 64% for all other patients in IRS I and IRS II (P = 0.48). Aggressive treatment is needed in children with perineal sarcoma to improve their prognosis.

The tal gene undergoes chromosome translocation in T cell leukemia and potentially encodes a helix-loop-helix protein

We have analyzed t(1;14)(p32;q11) chromosome translocations from two patients with T cell acute lymphocytic leukemia. The chromosome 1 breakpoints of these patients lie within a kilobasepair of each other, and thus define a genetic locus (designated tal) involved in T cell oncogenesis. Moreover, we have identified sequences within tal that potentially encode an amphipathic helix-loop-helix motif, a DNA-binding domain found in a variety of proteins that control cell growth and differentiation. The homology domain of tal is especially related to that of lyl-1, a gene on chromosome 19 that has also been implicated in T cell oncogenesis. Hence, tal and lyl-1 encode a distinct family of helix-loop-helix proteins involved in the malignant development of lymphocytes.

Expression of the multidrug resistance, MDR1, gene in neuroblastomas

Metastatic neuroblastoma is a childhood malignancy that is frequently responsive to chemotherapy with doxorubicin, vincristine, and teniposide (VM26), among other drugs, but in the majority of treated patients, the tumor recurs during or after chemotherapy. In this work, we have examined the hypothesis that the development of resistance to chemotherapy in neuroblastoma might be related to the expression of the human MDR1 gene, which encodes a multidrug transporter that functions as an energy-dependent drug efflux pump. RNA samples from 49 neuroblastomas were analyzed, including 31 from untreated and 18 from treated patients. MDR1 RNA was detectable in the majority of treated and untreated tumors using a sensitive, semiquantitative slot blot assay. Of the samples from treated patients, five of 18 were found to have high MDR1 RNA levels, whereas only three of 31 from untreated patients had high MDR1 levels, a statistically significant difference (P less than .01). These results show that high levels of MDR1 RNA are often associated with resistance to chemotherapy in neuroblastoma and suggest that they may contribute to this resistance. Many of the neuroblastoma samples were also evaluated for N-myc amplification but there was no correlation between N-myc copy number and the level of MDR1 mRNA expression.

Prognostic importance of the pre-B-cell immunophenotype and other presenting features in B-lineage childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

We report the prognostic significance of the pre-B-cell immunophenotype and other presenting features, including blast cell karyotype, in a randomized clinical trial conducted from 1981 to 1986 for children with early pre-B (n = 685) or pre-B (n = 222) acute lymphoblastic leukemia (ALL). Patients greater than or equal to 1 year and less than or equal to 21 years of age who attained complete remission were stratified by conventional risk criteria and immunophenotype and then randomized to receive continuation therapy with either of two regimens of intensive chemotherapy, designated S (standard) and SAM (standard plus intermediate-dose methotrexate, 1 g/m2 every 8 weeks). The proportions of subjects achieving complete remission in the two phenotypically defined subgroups were identical, 96%. At a median follow-up time of 42 months, the overall probability of 4-year event-free survival (+/- SE) was 63% +/- 2% (pre-B = 51% +/- 5% and early pre-B = 66% +/- 3%). Children with pre-B ALL had significantly shorter durations of continuous complete remission (P = .0004); this association included both bone marrow and CNS remissions (P = .0004 and P = .02, respectively). In a univariate Cox regression analysis of potentially important prognostic factors, the pre-B immunophenotype was significantly related to a poorer outcome, as were other recognized biologic and clinical features (eg, pseudodiploidy, older age, male sex, black race, and a higher WBC). It retained its prognostic strength in a multivariate model based on age, WBC, ploidy, and sex. The risk of failure at any point in the clinical course of a child with the pre-B immunophenotype was 1.8 times as great as that in a patient lacking this feature but otherwise having an equivalent risk status. It should be stressed that the predictive value of any of the significant characteristics identified in this study could diminish in the context of another, more effective treatment program. Nevertheless, our major conclusion, that children with pre-B ALL fare worse than those with early pre-B disease in a contemporary clinical trial has implications for stratified randomization of patients and the design of risk-specific treatment protocols.

Localization of preferential sites of rearrangement within the BCR gene in Philadelphia chromosome-positive acute lymphoblastic leukemia

The Philadelphia chromosome associated with acute lymphoblastic leukemia (ALL) has been linked to a hybrid BCR/ABL protein product that differs from that found in chronic myelogenous leukemia. This implies that the molecular structures of the two chromosomal translocations also differ. Localization of translocation breakpoints in Philadelphia chromosome-positive ALL has been impeded due to the only partial characterization of the BCR locus. We have isolated the entire 130-kilobase BCR genomic locus from a human cosmid library. A series of five single-copy genomic probes from the 70-kilobase first intron of BCR were used to localize rearrangements in 8 of 10 Philadelphia chromosome-positive ALLs. We have demonstrated that these breakpoints are all located at the 3' end of the intron around an unusual restriction fragment length polymorphism caused by deletion of a 1-kilobase fragment containing Alu family reiterated sequences. This clustering is unexpected in light of previous theories of rearrangement in Philadelphia chromosome-positive chronic myelogenous leukemia that would have predicted a random dispersion of breakpoints in the first intron in Philadelphia chromosome-positive ALL. The proximity of the translocation breakpoints to this constitutive deletion may indicate shared mechanisms of rearrangement or that such polymorphisms mark areas of the genome prone to recombination.

Treatment intensity and outcome for children with acute lymphocytic leukemia of standard risk. A Pediatric Oncology Group Study

Four hundred thirty-four children, with good-risk acute lymphocytic leukemia (ALL), were assigned randomly to receive intensive or less intensive maintenance therapy with 6-mercaptopurine and methotrexate, plus vincristine and prednisone pulses in such a way that patients on treatment 1 had their leukocyte counts maintained between 1500 and 3000/mm3. Patients on treatment 2 had leukocyte counts maintained between 3000 and 4500/mm3. Absolute granulocyte counts were maintained above 500/mm3 on both groups. All children received induction treatment with vincristine, prednisone and L-asparaginase and had central nervous system (CNS) prophylaxis with cranial irradiation and intrathecal methotrexate. The overall remission rate was 94%. Event-free survival at 8 years was 44% (SE, 5.6%). There was no significant difference in outcome between treatments 1 and 2 (P = 0.83). The incidence of infection was similar overall and not significantly different between treatment arms.

Results of intensive therapy in children with localized alveolar extremity rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study

Preliminary analyses of treatment results and prognostic factors from the first Intergroup Rhabdomyosarcoma Study (IRS I) suggested that alveolar histology and extremity site were among factors associated with an adverse outcome in clinical group I patients whose tumors had been completely resected. A high incidence of alveolar histology among the extremity tumors compounded the problem. These findings prompted an amendment to IRS II shortly after the study opened. Therapy for patients with alveolar extremity tumors in groups I and II was changed to more intensive repetitive pulse vincristine, dactinomycin, and cyclophosphamide (VAC) for 2 years. The outcome of 44 patients who received intensive therapy on IRS II is compared with a control series of 30 patients who were treated on IRS I. The control patients received standard VAC therapy for 2 years or VA for 1 year. Half of group I control patients received local radiotherapy, whereas none was given to group I intensive therapy patients. In both studies group II patients received radiotherapy to the primary tumor site and to identified positive regional lymph nodes. Compared with the control group, patients given more intensive therapy had a longer disease-free survival (DFS) (69% v 43% at 3 years), but this was of marginal significance (P = .06). The overall survival difference (77% v 57% at 3 years) was not significant (P = .23). Despite the limited statistical evidence, there is some indication that intensive therapy improved the prognosis of children with localized alveolar rhabdomyosarcoma (RMS).

Expression of a multidrug resistance gene in human cancers

Many cancers have been cured by chemotherapeutic agents. However, other cancers are intrinsically drug resistant, and some acquire resistance following chemotherapy. Cloning of the cDNA for the human MDR1 gene (also known as PGY1), which encodes the multidrug efflux protein P-glycoprotein, has made it possible to measure levels of MDR1 RNA in human cancers. We report the levels of MDR1 RNA in greater than 400 human cancers. MDR1 RNA levels were usually elevated in untreated, intrinsically drug-resistant tumors, including those derived from the colon, kidney, adrenal gland, liver, and pancreas, as well as in carcinoid tumors, chronic myelogenous leukemia in blast crisis, and cell lines of non-small cell carcinoma of the lung (NSCLC) with neuroendocrine properties. MDR1 RNA levels were occasionally elevated in other untreated cancers, including neuroblastoma, acute lymphocytic leukemia (ALL) in adults, acute nonlymphocytic leukemia (ANLL) in adults, and indolent non-Hodgkin's lymphoma. MDR1 RNA levels were also increased in some cancers at relapse after chemotherapy, including ALL, ANLL, breast cancer, neuroblastoma, pheochromocytoma, and nodular, poorly differentiated lymphoma. Many types of drug-sensitive and drug-resistant tumors, including NSCLC and melanoma, contained undetectable or low levels of MDR1 RNA. The consistent association of MDR1 expression with several intrinsically resistant cancers and the increased expression of the MDR1 gene in certain cancers with acquired drug resistance indicate that the MDR1 gene contributes to multidrug resistance in many human cancers. Thus, evaluation of MDR1 gene expression may prove to be a valuable tool in the identification of individuals whose cancers are resistant to specific agents. The information may be useful in designing or altering chemotherapeutic protocols in these patients.

A comparison of two regimens for high-risk acute lymphocytic leukemia in childhood. A Pediatric Oncology Group Study

Four hundred thirty patients with high-risk acute lymphoid leukemia were entered on the acute leukemia in childhood protocol (AlinC 12) of the Pediatric Division of the Southwest Oncology Group (now the Pediatric Oncology Group) between 1976 and 1979. This study was a prospective randomized comparison of two regimens that had as their primary differences: (1) an intensification period with Cytoxan (cyclophosphamide) and asparaginase after induction; (2) a period of intravenous methotrexate before initiating maintenance; and (3) in the regimen that had those two additions, triple-drug chemoprophylaxis of the central nervous system (CNS) using methotrexate, hydrocortisone, and cytosine arabinoside as compared to cranial irradiation and intrathecal methotrexate. All patients received vincristine and prednisone induction, 6-mercaptopurine and methotrexate maintenance, and vincristine and prednisone pulse intensification. There was no significant difference in the rate of bone marrow relapse. However, overall disease-free survival favored the arm with intensification and chemoprophylaxis because of a lesser incidence of extramedullary relapse. Thus, for treatment 1 versus treatment 3 the two-sided P values were for overall disease-free survival 0.16; bone marrow relapses 0.13; all CNS relapses 0.04; and all extramedullary disease relapses 0.013. It is concluded that intensification as delivered in this protocol protects against testicular relapse and that chemoprophylaxis is adequate prophylaxis against isolated CNS relapse.

The Intergroup Rhabdomyosarcoma Study-I. A final report

The results of treatment of 686, previously untreated patients younger than 21 years with rhabdomyosarcoma or undifferentiated sarcoma, who were entered on Intergroup Rhabdomyosarcoma Study-I (IRS-I) were analyzed after a minimum potential follow-up time of 7 years. Patients in Clinical Group I (localized disease, completely resected) were randomized to receive either vincristine, dactinomycin, and cyclophosphamide (VAC) or VAC + radiation. At 5 years, approximately 80% of patients given either treatment were still disease-free and there was no significant difference between treatments in the overall percentages of patients surviving of 93% and 81%, respectively (P = 0.67). Patients in Clinical Group II (regional disease, grossly resected) were randomized to receive either vincristine and dactinomycin (VA) + radiation or VAC + radiation. At 5 years, 72% and 65% of the patients, respectively, were disease-free and there was no evidence of a difference between treatments (P = 0.46). The overall survival percentage at 5 years was approximately 72% for both treatments. Patients in Clinical Groups III (gross residual disease after surgery) and IV (metastatic disease) were randomized to receive either "pulse" VAC + radiation or "pulse" VAC + Adriamycin (doxorubicin) + radiation. The complete remission (CR) rate was 69% in Clinical Group III and 50% in IV, with no statistically significant difference in CR rates between treatments in either group. Those who achieved a CR had a nearly 60% chance of staying in remission for 5 years in Clinical Group III compared with approximately 30% in Clinical Group IV. The overall survival percentage at 5 years was 52% in Clinical Group III compared to 20% in Clinical Group IV (P less than 0.0001). The 5-year survival percentage for the entire cohort of 686 patients was 55%. Survival after relapse was poor, being 32% at 1 year and 17% at 2 years. The risk of distant metastasis was much greater than the risk of local recurrence within each clinical group, and there was no evidence of differing types of relapses between treatments. Primary tumors of the orbit and genitourinary tract carried the best prognosis, whereas tumors of the retroperitoneum had the worst prognosis. The authors conclude that for the therapeutic regimens evaluated there was no therapeutic advantage to including radiation in the treatment of Clinical Group I disease, or cyclophosphamide given as a daily low-dose oral regimen in the treatment of Clinical Group II disease or Adriamycin in the treatment of Clinical Groups III and IV diseases.

Expression of a distinctive BCR-ABL oncogene in Ph1-positive acute lymphocytic leukemia (ALL)

The Philadelphia chromosome (Ph1) is a translocation between chromosomes 9 and 22 that is found in chronic myelogenous leukemia (CML) and a subset of acute lymphocytic leukemia patients (ALL). In CML, this results in the expression of a chimeric 8.5-kilobase BCR-ABL transcript that encodes the P210BCR-ABL tyrosine kinase. The Ph1 chromosome in ALL expresses a distinct ABL-derived 7-kilobase messenger RNA that encodes the P185ALL-ABL protein. Since the expression of different oncogene products may play a role in the distinctive presentation of Ph1-positive ALL versus CML, it is necessary to understand the molecular basis for the expression of P185ALL-ABL. Both P210BCR-ABL and P185ALL-ABL are recognized by an antiserum directed to BCR determinants in the amino-terminal region of both proteins. Antisera to BCR determinants proximal to the BCR-ABL junction in CML immunoprecipitated P210BCR-ABL but not P185ALL-ABL. Nucleotide sequence analysis of complementary DNA clones made from RNA from the Ph1-positive ALL SUP-B15 cell line, and S1 nuclease protection analysis confirmed the presence of BCR-ABL chimeric transcripts in Ph1-positive ALL cells. In Ph1-positive ALL, ABL sequences were joined to BCR sequences approximately 1.5 kilobases 5' of the CML junction. P185ALL-ABL represents the product of a BCR-ABL fusion gene in Ph1-positive ALL that is distinct from the BCR-ABL fusion gene of CML.