Final results of phase II trial of doxorubicin HCl liposome injection followed by bexarotene in advanced cutaneous T-cell lymphoma.

BACKGROUND: High response rates for doxorubicin HCl liposome injection (DLI) in cutaneous T-cell lymphoma (CTCL) have been reported with vague criteria until recently. Approximately 50% of CTCL patients respond to bexarotene (Bex). PATIENTS AND METHODS: A phase II trial was carried out to clarify the true overall response rate (ORR) for DLI and to assess the role of sequential Bex. Patients were treated with DLI 20 mg/m(2) i.v. every 2 weeks for 16 weeks (8 doses) followed by 16 weeks with Bex 300 mg/m(2) orally. Response assessments were carried out after 16 (DLI) and 32 weeks (Bex). Skin responses were measured by the modified Severity-Weighted Assessment Tool (mSWAT) and the Composite Assessment of Index Lesion Severity (CA). RESULTS: Thirty-seven patients were treated: stage IV (22, 8 with Sézary syndrome), IIB (10), earlier stage refractory to skin-directed therapies or radiation therapy (5). For 34 assessable patients: ORR 14/34 [41%: partial response (PR) 12, clinical complete response (CCR) 2]. Maximum responses were all seen after 16 weeks DLI. Median progression-free survival (PFS) was 5 months. There were 22 deaths: 21 of disease and 1 of heart failure. Twenty-seven grade 3 and 5 grade 4 toxic events were observed. CONCLUSION(S): With strict criteria, DLI ORR is among the highest reported for single agents in CTCL. Sequential Bex did not increase the response rate or duration.

Chemotherapy only for localized Hodgkin lymphoma.

Radiation therapy (RT) alone and more recently in combination with chemotherapy (combined modality therapy; CMT) has been the cornerstone of curative treatment for early-stage Hodgkin lymphoma (HL) for over 40 years. Because of increasing awareness of the late morbidity and mortality associated with RT, recent treatment regimens have attempted to limit its use. Chemotherapy only has been demonstrated to be a treatment option for most patients with localized HL. Current clinical trials have targeted subgroups of such patients who may be at an increased risk of recurrence for the addition of limited RT to chemotherapy.

Stanford V program for locally extensive and advanced Hodgkin lymphoma: the Memorial Sloan-Kettering Cancer Center experience.

BACKGROUND: The Stanford group has reported excellent results with the Stanford V regimen for patients with bulky and/or advanced Hodgkin lymphoma (HL). However, Gobbi reported markedly inferior failure-free survival (FFS) comparing Stanford V to other regimens but included major deviations from the original program. We retrospectively examined whether treatment at our institution carefully following Stanford V guidelines would confirm the original Stanford outcome data. PATIENTS AND METHODS: From June 1995 to May 2002, 126 patients with either locally extensive or advanced HL were treated with the 12-week Stanford V chemotherapy program followed by 36-Gy involved-field radiotherapy to sites initially > or =5 cm and/or to macroscopic splenic disease. Overall, 26% had stage IV disease and 20% had international prognostic score (IPS) > or =4. Overall survival (OS), disease-specific survival, progression-free survival (PFS), FFS, and freedom from second relapse (FF2R) were determined. RESULTS: The 5- and 7-year OS were 90% and 88%, respectively. The 5-year FFS was 78%. IPS > or =4 was a significant independent predictor of worse OS and PFS. The FF2R was 64% at 3 years. CONCLUSION: Stanford V with appropriate radiotherapy is a highly effective regimen for locally extensive and advanced HL.

Maintaining the dose intensity of ICE chemotherapy with a thrombopoietic agent, PEG-rHuMGDF, may confer a survival advantage in relapsed and refractory aggressive non-Hodgkin lymphoma.

INTRODUCTION: HDT/ASCT is standard for relapsed and refractory DLCL patients responding to second-line chemotherapy. We incorporated a thrombopoietic agent into the ICE chemotherapy program to potentially: decrease platelet associated toxicities, augment stem cell collection and maintain dose intensity. METHODS: This randomized, double-blind, placebo-controlled phase I/II trial examines PEG-rHuMGDF versus placebo with ICE chemotherapy. Phase I compared three cohorts and defined a clinically effective dose (CED). Phase II evaluated the CED versus placebo. Outcome measures included safety, hematological end-points, stem cell collection and the impact of dose-intensity on outcome. RESULTS: Forty-one patients with primary refractory (16) or relapsed DLCL (25) were treated; Response rates for evaluable patients are: 75% (12/16) for placebo and 82% (18/22) for PEG-rHuMGDF. PEG-rHuMGDF treated patients had significantly less grade IV thrombocytopenia, higher median platelet nadirs, and less platelet transfusion per cycle. ICE dose intensity was improved with PEG-rHuMGDF versus placebo: 75 versus 42% (P = 0.008). At 8.5 years median follow-up, overall and event-free survival are 47 and 31%, respectively. Patients treated on PEG-rHuMGDF versus placebo had improved survival (59 versus 31%, P = 0.06). CONCLUSION: PEG-rHuMGDF ameliorated thrombocytopenia, improved platelet recovery, and maintained ICE dose intensity. Potential survival advantages conferred by maintaining dose intensity require validation with newer thrombopoietic agents.

The NHL-15 protocol for aggressive non-Hodgkin's lymphomas: a sequential dose-dense, dose-intense regimen of doxorubicin, vincristine and high-dose cyclophosphamide.

BACKGROUND: The NHL-15 protocol is a novel, dose-intense, dose-dense, sequential chemotherapy program developed to improve outcome in advanced, aggressive non-Hodgkin's lymphomas. PATIENTS AND METHODS: The phase II NHL-15 protocol comprised: (i) induction [doxorubicin 60 mg/m(2) i.v. on weeks 1, 3, 5 and 7 plus vincristine 1.4 mg/m(2) i.v. (no cap) on weeks 1, 2, 3, 5 and 7]; and (ii) consolidation (cyclophosphamide 3000 mg/m(2) i.v. on weeks 9, 11 and 13 plus granulocyte colony-stimulating factor 5 microg/kg subcutaneous on days 3-10 following each cyclophosphamide dose). Patients with aggressive non-Hodgkin's lymphomas (working formulation: intermediate grade or immunoblastic), bulky stage I and stages II-IV, were eligible. RESULTS: There are 165 eligible patients with a 6.9-year median follow-up (range 0.5-141 months) and a median age of 48 years. For the entire group, 72.1% achieved complete remission, and at 5 years disease-free survival was 57.8% and overall survival (OS) was 62.2%. Ideal dose delivery was >90%. Acute and late toxicities of treatment were manageable and acceptable. Toxic death on treatment was 2.4%. When the diffuse large cell lymphoma histologies were grouped according to the International Prognostic Index (IPI), complete remission and OS in the low-intermediate (LI), and high-intermediate (HI) risk groups were improved by 5%-15% compared with historical CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone). This improvement was also noted for LI and HI risk groups in the age-adjusted (aa)IPI analysis for patients < or =60 years of age. CONCLUSIONS: The NHL-15 program can be administered safely and effectively to achieve high rates of durable remission when used for the treatment of advanced stage, aggressive, non-Hodgkin's lymphomas. The 5%-15% improvement in 5-year OS compared with historical CHOP, according to the IPI/aaIPI model (in LI and HI risk groups), is encouraging. Further evaluation and prospective testing of the NHL-15 protocol appears to be warranted.

HIV-associated lymphomas.

Intermediate and high-grade non-Hodgkin lymphomas (NHL) with a B-cell phenotype are AIDS-defining illnesses. The incidence of systemic NHL is over 100 times increased, primary central nervous system NHL is over 3000 times increased, and Hodgkin's disease is approximately 10 times increased in the HIV-infected population. Unusual extranodal presentations of NHL and Hodgkin's disease are seen in HIV-infected individuals. High-grade histologies are common for both NHL and Hodgkin's disease in the HIV setting. Treatment approaches may be changing with the advent of highly active antiretroviral therapy, which may allow patients to tolerate more intensive treatment.

Granulocyte-colony stimulating factor (G-CSF) may improve disease outcome in elderly patients with diffuse large cell lymphoma (DLCL) treated with CHOP chemotherapy.

Advanced age is an adverse prognostic factor in patients with DLCL. CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) has frequent dose-limiting toxicities, including myelosuppression. We retrospectively reviewed 50 consecutive patients > 60 years of age (median age 72) with B-cell DLCL who received CHOP with G-CSF. Patients received CHOP (median 6 cycles) at three-week intervals. G-CSF was given following all cycles of chemotherapy ("prophylactic G-CSF") in 28 of 50 patients, and following an episode of febrile neutropenia and thereafter in 19 patients, according to ASCO guidelines. Dose intensity, treatment delays, episodes of febrile neutropenia, complete response (CR) rate, disease-free survival, time-to-treatment failure, and overall survival were all analyzed according to the age-adjusted International Prognostic Index (aaIPI). The actual dose intensity for cyclophosphamide was 225.9 mg/m2/week and 0.90, respectively and for doxorubicin was 14.9 mg/m2/week (90% of ideal CHOP dosing for both drugs). Median followup was 4 years for the patients still living. Treatment delays and episodes of febrile neutropenia were less frequent among patients receiving G-CSF with all cycles of CHOP. The CR rates were 100%, 81%, 85%, and 36% for the low, low-intermediate, high-intermediate, and high aalPI risk groups, respectively. The 5-year actuarial relapse-free and overall survival for our patients were comparable to that of the cohort < or = 60 years of age and superior to the > 60 years of age cohort used to establish the aaIPI. With optimization of CHOP dosing, advanced age may not be an adverse prognostic factor for patients with DLCL. The routine use of G-CSF in elderly patients with DLCL should be further investigated.

Abnormal flow volume loops in patients with intrathoracic Hodgkin's disease.

STUDY OBJECTIVES: To study the incidence of upper airway obstruction, as measured on the flow volume loop (FVL), in patients with bulky mediastinal Hodgkin's disease; to correlate the FVL with CT of the chest; and to follow the changes in the FVL after treatment of the tumor. DESIGN: Retrospective study of pulmonary function tests (PFTs) and chest CTs performed as part of a clinical trial for Hodgkin's disease. SETTING: Memorial Sloan-Kettering Cancer Center, a comprehensive cancer care center. PATIENTS: Twenty-five patients (15 men and 10 women; age range, 20 to 57 years) with bulky mediastinal Hodgkin's disease enrolled in a clinical trial of chemotherapy followed by external beam radiation therapy. MEASUREMENTS AND RESULTS: Fourteen of 25 patients (56%) had an abnormal FVL prior to therapy; after chemotherapy, only 7 of 25 patients (28%) had an abnormal FVL. The abnormal patterns seen were either those typical of fixed obstruction or variable extrathoracic obstruction. No patient had a pattern typical of variable intrathoracic obstruction. On chest CT scan, 16 patients had grade-I tracheal deformity; 6 had grade-II deformity, and 3 had grade-III deformity. All three patients with grade-III deformity had a fixed obstruction pattern, as did three patients with a grade-I pattern. Patients with a fixed pattern on FVL had significant decreases in inspiratory and expiratory flow rates. CONCLUSION: FVL abnormalities suggesting upper airway obstruction occurred in > 50% of patients with bulky mediastinal Hodgkin's disease. A fixed pattern of obstruction was associated with the lower flow rates and severe tracheal distortion on CT; these patients may warrant special attention prior to general anesthesia or invasive procedures. Asymptomatic patients with abnormal FVLs but normal tracheal profiles need not undergo extensive evaluation. No patients showed the expected pattern typical of intrathoracic obstruction, but rather the major effect was on the inspiratory loop. The authors speculate on the mechanism for this unexpected finding.

The International Prognostic Index predicts for outcome following autologous stem cell transplantation in patients with relapsed and primary refractory intermediate-grade lymphoma.

We analyzed a group of 51 patients with primary refractory and relapsed intermediate-grade lymphoma (IGL) from the time of initiation of three cycles of second-line chemotherapy, ifosfamide, carboplatin and etoposide (ICE), in whom the intent was to administer curative high-dose chemoradiotherapy and autologous stem cell transplantation (ASCT). We sought to determine if the International Prognostic Index (IPI) assessed immediately prior to ICE, second-line IPI (sIPI), was predictive of outcome. The response rate to ICE-based chemotherapy was 69%, and 47% of the transplanted patients remain failure-free at 2.5 years. Stratification of patients based upon the sIPI demonstrated a superior 2.5 year failure-free survival (FFS) curve for patients with low (I) or low-intermediate (II) risk disease vs. those with high-intermediate (III) and high (IV) risk disease (45% vs. 9%, P<0.001). When the analysis was restricted to those patients with chemosensitive disease, the sIPI (I/II vs. III/IV) also separated patients into two distinct prognostic groups (59% vs. 20%, P = 0.04). Patients with sIPI I and II disease have a favorable outcome with ICE chemotherapy and ASCT. However, patients with sIPI III and IV disease derive limited benefit from this treatment strategy, and new approaches are needed in this patient group.

Prognostic factors in the treatment of human immunodeficiency virus-associated non-Hodgkin's lymphoma: analysis of AIDS Clinical Trials Group protocol 142--low-dose versus standard-dose m-BACOD plus granulocyte-macrophage colony-stimulating factor. National Institute of Allergy and Infectious Diseases.

PURPOSE: The overall results of chemotherapy in human immunodeficiency virus (HIV)-associated non-Hodgkin's lymphoma (NHL) have been poor. To define a subgroup of patients who may have a better outcome, an analysis of prognostic factors was performed of patients treated in AIDS Clinical Trials Group (ACTG) protocol 142, a phase III randomized trial of low-dose versus standard-dose methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone (m-BACOD) plus granulocyte-macrophage colony-stimulating factor (GM-CSF) for the treatment of patients with newly diagnosed HIV-associated NHL. MATERIALS AND METHODS: The following baseline variables were included as potential predictors of survival among 192 patients who received treatment: age; intravenous drug use (IVDU); specific type of sexual contact as risk factors (homosexual, bisexual, or heterosexual contact); prior AIDS diagnosis; CD4 cell count; serum lactic acid dehydrogenase (LDH); histology; Karnofsky performance status (KPS); stage; B symptoms; race (white/nonwhite); nodal involvement; extranodal involvement; number of extranodal sites; specific sites: bone marrow, liver, kidney, lung, or gastrointestinal tract; and treatment arm (standard-dose m-BACOD/low-dose m-BACOD). RESULTS: Age greater than 35 years, IVDU, stages III/IV, and CD4 cell counts less than 100/microL were adverse prognostic factors in multivariate analyses using the Cox proportional hazards model. The median overall survival for patients with none or one of the adverse factors was 46 weeks, with two was 44 weeks, and with three or four was 18 weeks. At 144 weeks, 29.5% of patients with none or one, 16.9% with two, and 0% with three or four factors were alive (P < .001). CONCLUSION: Long-term survival can be achieved in approximately one third of patients with HIV-associated NHL with favorable characteristics.

HIV-associated lymphomas.

Intermediate and high-grade non-Hodgkin's lymphomas (NHL) with a B-cell phenotype are AIDS-defining illnesses. The incidence of systemic NHL increased greatly and primary central nervous system NHL increased even more in the HIV-infected population. Further increases in frequency are anticipated as HIV-infected individuals survive longer in an immunosuppressed state with improved antiretroviral treatment and treatment of opportunistic infections. Unusual types of NHL and manifestations of Hodgkin's disease are seen in HIV-infected individuals also. The pathologic and clinical features of the HIV-associated lymphomas and treatment approaches and results are the subjects of this review. Other articles in this issue discuss epidemiology and pathogenesis.

Low-dose compared with standard-dose m-BACOD chemotherapy for non-Hodgkin's lymphoma associated with human immunodeficiency virus infection. National Institute of Allergy and Infectious Diseases AIDS Clinical Trials Group.

BACKGROUND: Reduced doses of cytotoxic chemotherapy or standard-dose therapy plus a myeloid colony-stimulating factor decreases hematologic toxicity and its complications in patients with non-Hodgkin's lymphoma associated with infection with the human immunodeficiency virus (HIV). However, the effect of reducing the doses of cytotoxic chemotherapeutic agents on clinical outcome is not known. METHODS: We randomly assigned 198 HIV-seropositive patients with previously untreated, aggressive non-Hodgkin's lymphoma to receive standard-dose therapy with methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone (m-BACOD) along with granulocyte-macrophage colony-stimulating factor (GM-CSF; n=94) or reduced-dose m-BACOD with GM-CSF administered only as indicated (n=98). RESULTS: A complete response was achieved in 39 of the 94 assessable patients assigned to low-dose therapy (41 percent) and in 42 of the 81 assessable patients assigned to standard-dose therapy (52 percent, P= 0.56). There were no significant differences in overall or disease-free survival; median survival times were 35 weeks for patients receiving low-dose therapy and 31 weeks for those receiving standard-dose therapy (risk ratio for death in the standard-dose group=1.17; 95 percent confidence interval, 0.84 to 1.63; P=0.25). Toxic effects of chemotherapy rated grade 3 or higher occurred in 66 of 94 patients assigned to standard-dose therapy (70 percent) and 50 of 98 patients assigned to low-dose treatment (51 percent, P=0.008). Hematologic toxicity accounted for the difference. CONCLUSIONS: As compared with treatment with standard doses of cytotoxic chemotherapy (m-BACOD), reduced doses caused significantly fewer hematologic toxic effects yet had similar efficacy in patients with HIV-related lymphoma. Dose-modified chemotherapy should be considered for most HIV-infected patients with lymphoma.

Human immunodeficiency virus-associated lymphomas.

Lymphomas associated with human immunodeficiency virus (HIV) will probably become an increasing problem with improved survivals of infected individuals in an immunosuppressed state because of the advances in antiretroviral treatment and the therapy of opportunistic infections. In an attempt to aid the understanding of the many aspects of the this growing problem, the current thinking about the epidemiology, pathology, biological and clinical features, and treatment of the systemic HIV-associated non-Hodgkin lymphomas is reviewed. The important features of the HIV-associated central nervous system lymphomas are also described. Finally, there is a discussion of Hodgkin's disease in HIV-infected individuals.

Treatment of Hodgkin's disease: the role of radio- and/or chemotherapy in advanced stages.

In recent years, anthracycline-containing single, alternating or "hybrid' combination chemotherapy regimens have achieved superior results in the treatment of patients with advanced Hodgkin's disease to those with single regimens of the MOPP type. A number of studies also suggest the superiority of combined modality regimens with chemotherapy and radiation therapy to chemotherapy alone among this group of patients. These studies and recent analyses of prognostic factors among patients treated with these current treatment approaches have been the subjects of this brief review.

CD30 (Ki-1)-positive malignant lymphomas: clinical, immunophenotypic, histologic, and genetic characteristics and differences with Hodgkin's disease.

This study compares the histologic and immunophenotypic features of 71 cases of primary CD30+ diffuse large-cell lymphomas (DLCL) and 128 cases of Hodgkin's disease (HD) and discusses the clinical features of 52 patients with CD30+ DLCL. It includes analysis of sites of involvement, staging, response to treatment, sites and treatment of recurrences, and disease-free and overall survival. Diagnostic immunophenotypic differences were found between CD30+ DLCL and HD. All cases of CD30+ DLCL were positive for one or more common or lineage-specific lymphocyte antigens or for EMA. In contrast, 96.9% of HD cases were negative for CD45, CD45-RO, CD43, and CD20. The four exceptions are discussed. All cases of HD were negative for EMA. In patients with CD30+ DLCL, a T-cell phenotype was found in 60%, a null-cell type in 22%, and a B-cell type in 18% of the cases. The median age of patients with T- and null-cell phenotype was 22 years (range, 4 to 72). Fifty-two percent of them had high-stage (III and IV) disease and 61% had extranodal involvement at presentation, including 25% with skin lesions. Lymph nodes draining the skin lesions became involved in seven of 11 patients. No patient had initial bone marrow involvement. Most patients were treated with chemotherapy, and 83% had a complete remission. Fifty-four percent remain free of disease with a median follow-up of 47 months. Thirteen patients (29%) had one or more recurrences and five of them remain free of disease after salvage therapy, with a median follow-up period of 79 months. The clinical stage did not affect survival, probably as a result of different therapy. The t(2;5) translocation was found in five of 15 patients who had cytogenetic abnormalities. Of the other 10 cases, the translocation was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in four of five cases studied. All nine cases were of T- or null-cell phenotype. The cases of B-cell CD30+ DLCL had a characteristic immunophenotype. All were negative for EMA. These patients were older and had frequent bone marrow involvement but no skin infiltration by lymphoma. All three patients who were human immunodeficiency virus-positive (HIV+) had lymphomas of B-cell lineage. Detection of the t(2;5) translocation by molecular genetics is a useful and highly specific marker in the differential diagnosis between HD and CD30+ DLCL.

Effect of ABVD chemotherapy with and without mantle or mediastinal irradiation on pulmonary function and symptoms in early-stage Hodgkin's disease.

PURPOSE: To evaluate the effect of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) chemotherapy alone and of ABVD with mantle or mediastinal irradiation (RT) on the pulmonary function of patients with early-stage Hodgkin's disease. PATIENTS AND METHODS: Between 1989 and 1993, 60 patients with clinical stage I to IIIA HD enrolled onto randomized trials at Memorial Sloan-Kettering Cancer Center (MSKCC) underwent prospective evaluation of pulmonary function. All patients received six cycles of ABVD, and 30 patients received mantle or mediastinal RT. Pulmonary function tests (PFTs) and symptom evaluation were conducted before, during, and after completion of chemotherapy and RT, and at various intervals thereafter. The median follow-up time was 30 months. RESULTS: During chemotherapy, symptoms of cough and dyspnea on exertion developed in 32 of 60 patients (53%) and declines in pulmonary function occurred in 22 of 60 patients (37%). Discontinuation of bleomycin was necessary in 14 of 60 patients (23%). Following chemotherapy, there was a significant decline in median forced vital capacity (FVC) and diffusing capacity of carbon monoxide (DLCO). In patients who received mantle or mediastinal RT, there was a further decline in FVC following radiation therapy. At the most recent follow-up evaluation, five of 29 patients (18%) who received ABVD alone and nine of 30 (30%) who received ABVD and RT reported persistent mild pulmonary symptoms (P = .36), which did not significantly affect normal daily activity. CONCLUSION: ABVD chemotherapy induced acute pulmonary toxicity that required bleomycin dose modification in a substantial number of patients. The addition of RT resulted in a further decrease in FVC; however, this did not significantly affect the functional status of patients.

Treatment of Burkitt's lymphoma in HIV-positive patients.

Many Burkitt's-type non-Hodgkin lymphomas (NHL) in patients without HIV infection are curable with current brief high-dose combination chemotherapy regimens. Burkitt's-type lymphomas (BL) comprise 30-40% of HIV-associated NHL. Their morphologic, clinical, cytogenetic and molecular genetic characteristics are similar to those of sporadic BL unassociated with HIV infection. They often occur in less immunosuppressed HIV-infected individuals than the other types of NHL. Most patients with HIV-associated NHL benefit as much from low-dose as from standard or high-dose chemotherapy with less toxicity. However, there may be a subpopulation of HIV-infected patients with Burkitt's-type NHL and well preserved immune status who may benefit from high-dose chemotherapy programs that are effective for BL patients without HIV infection.

Phase I dose-escalation trial of iodine 131-labeled monoclonal antibody OKB7 in patients with non-Hodgkin's lymphoma.

PURPOSE: Eighteen patients with recurrent or refractory CD21-positive, non-Hodgkin's lymphoma (NHL) were treated in a phase IA dose-escalation therapeutic trial of iodine 131 labeled to a fixed dose of OKB7. METHODS: Individual doses of 30 to 50 mCi of 131I on 25 mg OKB7 were administered 2 to 3 days apart to achieve four total 131I-OKB7 dose levels of 90, 120, 160, and 200 mCi. Pharmacology, dosimetry, therapeutic effects, toxicity, human anti-mouse antibody (HAMA) response, and maximum-tolerated dose (MTD) were determined. Patients were evaluated by imaging studies (including whole-body gamma camera or single-photon emission computed tomography [SPECT] scans), flow cytometric analysis, bone marrow biopsy, and serial blood sampling. RESULTS: Median plasma and whole-body half-lives (T1/2) were 16 hours and 14 hours, respectively. Plasma and whole-body radiation doses were 0.0081 Gy/mCi and 0.0022 Gy/mCi, respectively. Specific tumor visualization was noted in eight of 18 patients. HAMA was detected in 12 of 16 patients. Nonhematologic toxicity was limited to asymptomatic elevations of thyroid-stimulating hormone (TSH) in five of 15 patients. Hematologic toxicity was observed in six of 18 patients, but was severe in only two patients. MTD in patients with diffuse lymphomatous bone marrow involvement was determined to be 200 mCi in four divided doses of 50 mCi 131I/25 mg OKB7. Antitumor activity was observed in 13 of 18 patients (one partial response [PR] and 12 mixed responses) and was dependent on the 131I-OKB7 dose administered. In general, palpable peripheral lymphadenopathy, enlarged spleens, skin lesions, and circulating OKB7-positive peripheral lymphocytes responded most readily to treatment. 131I-OKB7 was safely administered to a patient in leukemic phase of NHL with prompt subsequent loss of approximately 1 kg of tumor cells from the peripheral blood without associated tumor lysis syndrome. CONCLUSION: Because antitumor activity with tolerable toxicity was observed in the majority of this group of heavily pretreated patients, phase II investigation of mAb OKB7 radioconjugates in the therapy of NHL is warranted.