Unmaintained Complete Remission Research Articles

Treatment of aggressive Non‐Hodgkin's lymphoma in the elderly

A nonanthracycline-containing chemotherapeutic combination for the treatment of intermediate and high-grade non-Hodgkin's lymphoma was evaluated. Thirty-four consecutive and previously untreated patients, with a median age of 75 (range 54-86) years, with aggressive lymphoma, received daily etoposide (60 mg/m2 intravenous infusion [IVI]), cytosine arabinoside (50 mg/m2 subcutaneously), and methylprednisolone (60 mg/m2 IVI) on each of 5 consecutive days. Individuals with limited disease (stages I and II) (n = 9) received six, 3-day cycles of the same therapy and involved field radiation (36 Gy in 20 fractions) between the third and fourth courses. Patients with disseminated lymphoma (n = 25) received 10 cycles over 8 months of the same combination, with the addition of methotrexate (200 mg/m2 on days 8 and 15), followed by leucovorin rescue (10 mg/m2 orally every 6 hr for 8 doses). Of the 34 patients, 44% entered complete remission (CR), and 7 died before completing the first cycle of chemotherapy. Fifty-six percent of the patients with limited disease and 40% with disseminated lymphoma (P > 0.05) achieved CR. For all patients, median survival was 14 months (range 3 days- > 54 months), this being 12 and 15 months, respectively. For the entire population of responding patients, median survival has not been reached at a median follow-up of 39 months, while the median CR duration is 21 months. Ten of the 15 responders are alive in unmaintained CR at a median of 41 (range 30-54) months. Myelotoxicity was the major side effect, leading to adjustments in dose and schedule in two-thirds of the patients, although treatment changes did not affect outcome. Of the 15 deaths that occurred in this trial, in 53.3% it was unrelated to lymphoma or its therapy. Four patients that had achieved CR died of cardiovascular events (n = 2) or of progressive second malignancies (n = 2). It is concluded that cytosine arabinoside in combination regimens is effective in selected patients; this is particularly relevant in the elderly.

Successful Treatment of Multisystem Langerhans Cell Histiocytosis (Histiocytosis X) with Etoposide

Langerhans cell histiocytosis (LCH) in its disseminated form usually occurs in the very young, and has a fulminant, rapidly progressive, and fatal course despite different forms of therapy. We treated two patients, who had failed on vinblastine treatment, with i.v. etoposide (VP-16) at a dose of 150 mg/kg/day for 3 days. Patient I, 8 months of age, presented with failure to thrive and huge bilateral granulomatous lesions of the external auditory canal with erosion and extensive destruction of the petrous pyramids and mastoid area. Patient II, 20 months of age, presented with widespread purpuric skin rash, hepatosplenomegaly, and bone marrow involvement. Both patients sustained complete remission (CR) following three to six courses of VP-16 and continued to be in unmaintained CR for > 48 months from diagnosis. No major toxicity was noted. Etoposide (VP-16), an epipodophyllotoxin known for its usefulness in the treatment of malignancies of the monocyte/macrophage lineage, appears to be an effective treatment for the severe multisystem (disseminated) LCH of childhood and should be strongly considered as front-line therapy for this subgroup of patients with poor prognostic factors.

Absence of Reverse Transcription-Polymerase Chain Reaction Detectable Residual Disease in Patients With Acute Promyelocytic Leukemia in Long-Term Remission

Hybrid fusion genes are specific tumor markers of several leukemic subtypes. The use of reverse transcription-polymerase chain reaction (RT-PCR) to amplify chimeric cDNAs allows sensitive detection of the neoplastic clone for diagnostic and monitoring studies in these leukemias. Nonetheless, the clinical relevance of minimal residual disease (MRD) evaluation by PCR remains controversial. In this study, 9 patients (pts) with acute promyelocytic leukemia (APL) in long-term remission for 4 to 12 years were analyzed for the presence of MRD by RT-PCR amplification of the specific PML/RAR-alpha fusion gene. Seven pts had been treated with conventional chemotherapy (CHT) alone, 1 had undergone allogeneic bone marrow transplantation (BMT), and 1 autologous BMT as consolidation therapy after CHT. In 8 cases, the presence of the t(15;17) rearrangement could be documented in diagnostic BM specimens by cytogenetic and/or molecular analysis. A two-rounds "nested" RT-PCR assay with sensitivity levels of 1 in 10(5) was used to analyze BM samples collected at 32 to 141 months from the achievement of complete remission (CR). In no cases were residual PML/RAR-alpha transcripts detectable in these remission controls. All patients are in unmaintained CR at 48 to 154 months from CR and at 6 to 17 months from PCR evaluation. These results suggest that long-term survival of APL is associated with eradication of cells carrying the specific PML/RAR-alpha rearrangement, indicating that PCR negativity should be considered the therapeutic goal in these patients. Our findings further strengthen the clinical relevance of PCR monitoring studies in APL, as opposite to other leukemic subtypes (chronic myeloid leukemia and acute myeloid leukemia-M2) in which the prognostic significance of PCR evaluation is unclear.

Absence of reverse transcription-polymerase chain reaction detectable residual disease in patients with acute promyelocytic leukemia in long- term remission

Hybrid fusion genes are specific tumor markers of several leukemic subtypes. The use of reverse transcription-polymerase chain reaction (RT-PCR) to amplify chimeric cDNAs allows sensitive detection of the neoplastic clone for diagnostic and monitoring studies in these leukemias. Nonetheless, the clinical relevance of minimal residual disease (MRD) evaluation by PCR remains controversial. In this study, 9 patients (pts) with acute promyelocytic leukemia (APL) in long-term remission for 4 to 12 years were analyzed for the presence of MRD by RT- PCR amplification of the specific PML/RAR-alpha fusion gene. Seven pts had been treated with conventional chemotherapy (CHT) alone, 1 had undergone allogeneic bone marrow transplantation (BMT), and 1 autologous BMT as consolidation therapy after CHT. In 8 cases, the presence of the t(15;17) rearrangement could be documented in diagnostic BM specimens by cytogenetic and/or molecular analysis. A two- rounds “nested” RT-PCR assay with sensitivity levels of 1 in 10(5) was used to analyze BM samples collected at 32 to 141 months from the achievement of complete remission (CR). In no cases were residual PML/RAR-alpha transcripts detectable in these remission controls. All patients are in unmaintained CR at 48 to 154 months from CR and at 6 to 17 months from PCR evaluation. These results suggest that long-term survival of APL is associated with eradication of cells carrying the specific PML/RAR-alpha rearrangement, indicating that PCR negativity should be considered the therapeutic goal in these patients. Our findings further strengthen the clinical relevance of PCR monitoring studies in APL, as opposite to other leukemic subtypes (chronic myeloid leukemia and acute myeloid leukemia-M2) in which the prognostic significance of PCR evaluation is unclear.

2-Chlorodeoxyadenosine: an active agent in the treatment of cutaneous T- cell lymphoma

Cutaneous T-cell lymphomas are disfiguring malignant lymphoproliferative disorders for which standard therapy has been principally palliative. 2-Chlorodeoxyadenosine (2-CdA), a new purine analogue resistant to degradation by adenosine deaminase that has substantial activity against lymphoid neoplasms, was administered to 16 patients with cutaneous involvement by T-cell lymphoma. All patients had failed topical treatment modalities and/or systemic therapies. Fifteen patients were evaluable; one patient was not evaluable due to incomplete therapy and follow-up. The overall response rate was 47%. Three of 15 patients (20%) achieved complete responses and four of 15 patients (27%) achieved partial responses. The median duration of response was 5 months. One patient remains in unmaintained complete remission at 52+ months. Therapy was well tolerated. Myelosuppression was the principal toxicity encountered, occurring in 8 of 15 (53%) patients. 2-CdA is an effective new agent for the treatment of cutaneous T-cell lymphoma and warrants further study both as a single agent and in combination regimens.

2-Chlorodeoxyadenosine: An Active Agent in the Treatment of Cutaneous T-Cell Lymphoma

Abstract Cutaneous T-cell lymphomas are disfiguring malignant lymphoproliferative disorders for which standard therapy has been principally palliative. 2-Chlorodeoxyadenosine (2-CdA), a new purine analogue resistant to degradation by adenosine deaminase that has substantial activity against lymphoid neoplasms, was administered to 16 patients with cutaneous involvement by T-cell lymphoma. All patients had failed topical treatment modalities and/or systemic therapies. Fifteen patients were evaluable; one patient was not evaluable due to incomplete therapy and follow-up. The overall response rate was 47%. Three of 15 patients (20%) achieved complete responses and four of 15 patients (27%) achieved partial responses. The median duration of response was 5 months. One patient remains in unmaintained complete remission at 52+ months. Therapy was well tolerated. Myelosuppression was the principal toxicity encountered, occurring in 8 of 15 (53%) patients. 2-CdA is an effective new agent for the treatment of cutaneous T-cell lymphoma and warrants further study both as a single agent and in combination regimens.

Long-term results of the HEAVD protocol for adult acute lymphoblastic leukaemia

Between 1979 and 1987, 82 adults (age 14-71 years) with acute lymphoblastic leukaemia (ALL) were treated with a 6-course protocol called HEAVD, the main feature of which was the early postremission administration of escalating doses of doxorubicin (total 405 mg/m2) and cyclophosphamide (total 2.5 g/m2). A complete remission (CR) was attained in 66 patients (80%, 95% confidence intervals, [CI] 71%-89%). Factors affecting favourable CR achievement were age less than 60 years and absence of lymphadenopathy-hepatosplenomegaly at presentation (P less than 0.05). Median duration of CR was 27 months. 26 patients remain in first continuous and unmaintained CR, 18 of whom between 5.9 and 11.1 years, for an estimated 39% prolonged disease-free survival (95% CI 27%-51%). CR duration correlated significantly with absolute blast cell count (15 x 10(9)/l or less compared to more) and age (30 years or under compared to over). Overall, 29 patients are alive with a median follow-up of 6.7 years, the projected long term survival being 35% at 11 years (95% CI 24%-46%). Treatment-related toxicity included 1 lethal case of L-asparaginase-related thromboembolism and 3 toxic deaths among 66 CR patients. Late-onset toxicity was not observed in long-term survivors. The relatively late occurrence of endpoint events (relapse and death) in adult ALL confirms that long-term updating is necessary to determine the curative potential of modern chemotherapy programs for the disease.

Autologous blood stem-cell transplantation in patients with advanced Hodgkin's disease and prior radiation to the pelvic site.

Patients with relapsed Hodgkin's disease who respond to salvage therapy are successfully treated with cyclophosphamide, carmustine (BCNU), and etoposide (VP-16) (CBV) followed by autologus bone marrow transplantation (ABMT). Because of heavy pretreatment including radiation to the pelvic site, marrow harvest was not feasible in those patients. We therefore used blood-derived hemopoietic precursor cells as an alternative stem-cell source to rescue them after superdose chemotherapy. Hemopoietic precursor cells were mobilized into the peripheral blood either by chemotherapeutic induction of transient myelosuppression followed by an overshooting of blood stem-cell concentration, or by continuous intravenous (IV) granulocyte-macrophage colony-stimulating factor (GM-CSF) administration. The median time to reach 1,000 WBC per microliter, 500 polymorphonuclear cells (PMN) per microliter, or 20,000 platelets per microliter was 10, 20.5, and 38 days, respectively, for 50% of all patients. The platelet counts of two patients never dropped below 20,000/microL following autologous blood stem-cell transplantation (ABSCT), whereas two other patients had to be supported with platelets for 75 and 86 days posttransplant until a stable peripheral platelet count of 20,000/microL was attained. Among the 11 assessable patients, seven are in unmaintained complete remission (CR) at a median follow-up of 318 days. This is a first report on a series of ABSCTs in patients with advanced Hodgkin's disease proving that, despite prior damage to the marrow site, the circulating stem-cell pool is still a sufficient source of hemopoietic precursor cells for stem-cell rescue.

Autologous bone marrow transplantation in B-cell non-Hodgkin's lymphoma: very low treatment-related mortality in 100 patients in sensitive relapse.

One hundred patients with B-cell non-Hodgkin's lymphoma (NHL) in sensitive relapse or incomplete first remission underwent high-dose chemoradiotherapy and anti-B-cell monoclonal antibody (MAb)-treated autologous bone marrow transplantation (ABMT). These patients demonstrated good performance status with a Karnofsky score of 80% or greater. The majority of these patients had one or more adverse prognostic features including a failure to achieve a complete remission (CR) with conventional combination chemotherapy (37 patients), bone marrow infiltration (69 patients), a history of extranodal disease other than bone marrow infiltration (42 patients), and histologic conversion (18 patients). At the time of ABMT, only 52 patients were in CR; however, all patients achieved a minimal disease state following conventional intensive therapy. Moreover, at the time of marrow harvest, 37 of these patients had histologic evidence of lymphoma cells infiltrating the marrow. Following high-dose ablative therapy, two acute in-hospital treatment-related deaths were observed. Two late deaths were observed, not due to recurrent lymphoma. Of the remaining 96 patients, 61 are in unmaintained CR with a median follow-up of 13 months. Kaplan-Meier actuarial analysis predicts 50% probability of disease-free survival (DFS) at 37.8 months. This very low treatment-related mortality provides the rationale to apply high-dose therapy and ABMT as consolidative therapy for patients in first remission who are at high risk for relapse following conventional therapy.

Long‐term bone marrow damage after chemotherapy for acute myeloid leukaemia does not improve with time

Thirteen patients with acute myeloid leukaemia (AML) who had been in unmaintained complete remission for at least 5 years following successful chemotherapy, were studied by marrow culture techniques regularly for periods of up to 5 years. In 10 patients, short-term clonal assay revealed the incidence of granulocyte-macrophage progenitor cells (GM-CFC) to be at the lower limit of the normal range; but three showed wide fluctuations in GM-CFC numbers. Moreover the generation of GM-CFC in long-term bone marrow culture (LTBMC) was impaired in eight of nine evaluable patients. These results suggest that, despite normal blood counts, impairment of haemopoiesis persists in patients who are long-term survivors of AML, and this does not improve with the passage of time.

The role of autologous bone marrow transplantation in 46 adult patients with non-Hodgkin's lymphomas.

Forty-six patients with non-Hodgkin's lymphoma (NHL) were treated with autologous bone marrow transplantation (ABMT) in two different institutions. All patients were pretreated with conventional chemotherapy. Three different conditioning regimens were used, and 20 patients underwent bone marrow purging. Twelve patients were treated in first complete remission (CR); eight are in unmaintained CR 8 to 104 months after ABMT. Five patients were grafted in first partial remission (PR) after conventional therapy; all achieved CR, and all remain in prolonged CR (first CR for four patients, second CR for one patient). Of 21 patients with chemosensitive relapses, 13 patients are in prolonged unmaintained CR 8 to 94 months after ABMT. Eight patients with resistant disease remained uncured by ABMT; all eight died, six from progressive illness and two from toxicity. The current 3-year disease-free probability is 60% for all patients, 0% for refractory disease; 82% for first PR or CR, and 60% for sensitive relapses (SRs). These results confirm the efficacy of ABMT in the treatment of chemosensitive NHL with bad prognosis.

Bone marrow transplantation for childhood Ki-1 lymphoma.

Two children with Ki-1 antigen-positive, non-Hodgkin's lymphoma received high-dose chemotherapy, fractionated total body irradiation (TBI), and allogeneic bone marrow transplantation. Both patients had relapsed multiple times on conventional chemotherapy and radiation therapy. Following transplantation, there was successful engraftment with disappearance of clinical signs and symptoms of their disease. As of June 1, 1989 they are in continuous unmaintained complete remission, 56 and 40 months, respectively, after bone marrow transplantation.

Cisplatin-based chemotherapy in advanced basal and squamous cell carcinomas of the skin: results in 28 patients including 13 patients receiving multimodality therapy.

This study reports the results of cisplatin (CDDP)-based chemotherapy (CT) as sole therapy and as neoadjuvant (NA) therapy in 28 consecutive patients (pts) with advanced basal cell (BC) and squamous cell (SC) cancers of the skin. CT in 24 pts consisted of CDDP 75 mgm/m2 and doxorubicin (Dox) 50 mg/m2 intravenously (IV) every 3 weeks with Dox being omitted in four pts due to severe preexisting cardiac disease. Thirteen of the 28 pts received CT in the NA setting, five before surgery and eight before radiation therapy (RT). Response rates to CT were complete remission (CR) in eight of 28 (28%) pts, partial remission (PR) in 11 of 28 (40%) for an overall response rate of 68%. Thirteen pts received a second treatment modality with five of 13 pts having a CR to CT alone before the second modality and seven converting to CR postsecond modality for a total CR rate of 12 of 13 (92%) in the multimodality group. Duration of responses in the CT-only group ranged from 4 to 82 months; however, only two patients remain in remission in this group. Of the twelve CRs from the multimodality therapy group, 11 of 12 (91%) pts remain in CR with duration of response ranging from 3 to 81 months. Toxicities were manageable, with no toxic deaths and only five pts stopped CT secondary to side effects. This study suggests the combination of CDDP and Dox is highly effective in BC and SC cancers of the skin and by itself can produce long unmaintained remissions, but when combined with a second modality of therapy, it is capable of producing not only long unmaintained CRs but probable cures in the majority of pts.

Early Hematopoietic Reconstitution after Autologous Transplantation with Blood-Derived Stem Cells in a Patient with Advanced Lymphoma

A 30-year-old man with advanced non-Hodgkin lymphoma underwent repeated leukaphereses for harvesting blood-derived hemopoietic stem cells. Collection was started 8-10 days after the end of L-VAMP therapy (3 cycles). Nine procedures were performed and a total of 65.4 x 10(9) mononuclear cells (0.87 x 10(9)/Kg) were collected, processed, cryopreserved and stored in liquid nitrogen. The yields of CFU-GM, BFU-E and CFU-GEMM were respectively 964 x 10(4) (12.4 x 10(4)/Kg), 249 x 10(4) (3.2 x 10(4)/Kg) and 798 x 10(4) (10.4 x 10(4]. The patient received a myeloblative regimen consisting of fractionated total body irradiation (1200 cGy) and cyclophosphamide (120 mg/kg) followed by infusion of his own thawed cells. Early trilineage hematopoietic recovery was first observed on day +8; 1 x 10(9)/l WBC were reached on day +11, 0.5 x 10(9)/l PMN on day +13 and 50 x 10(9)/l platelets on day +11. Course was uneventful and the patient was discharged from hospital on day +21. Eight months after transplant the patient is in continuous unmaintained complete remission with normal blood cell counts. This reports suggests that complete and sustained engraftment can be achieved with peripheral stem cells recruited after "soft" chemotherapy.

Lomustine, vindesine and bleomycin (LVB) used in the treatment of relapsed advanced Hodgkin's disease. A prospective study on behalf of the east of Scotland and Newcastle lymphoma group (ESNLG)

Sixty-three patients with relapsed advanced Hodgkin's disease were treated with lomustine (CCNU), vindesine and bleomycin (LVB). Age range was 17-72 years, with 38 males and 25 females. Thirty patients achieved complete remission (CR) with a median duration of 24+ months (range 3-55). Nineteen continue in unmaintained CR. CR rates were highest for those patients who relapsed greater than 6 months after first line treatment and for those at second or subsequent relapse. CR rates were higher in those with nodal only relapse. Twenty-seven patients were non-responders and six were partial responders. These 33 patients were subsequently changed to alternative chemotherapeutic regimes and 26 failed to respond to any therapy and have since died. Only one patient is in unmaintained complete remission. The regimen was well tolerated by patients, and easy to administer. It produced no serious episodes of toxicity. We conclude that LVB is of value in the management of relapsed advanced Hodgkin's disease especially in chronic relapsing patients, and where relapse occurs greater than 6 months after the first line treatment. We are presently unsure whether it offers any advantage over reintroduction of first line treatment in the latter group.

Membrane phenotype and response to deoxycoformycin in mature T cell malignancies.

The adenosine deaminase inhibitor deoxycoformycin was used in low doses to treat 19 patients with clinically aggressive T cell malignancy with a mature membrane phenotype. The patients comprised eight with prolymphocytic leukaemia, two with chronic lymphocytic leukaemia, four with adult T cell leukaemia-lymphoma, three with Sézary syndrome, and two with T cell lymphoma. Two thirds of the patients had been resistant or minimally responsive to combination chemotherapy. Complete remission was obtained in five patients (two with prolymphocytic leukaemia and one each with chronic lymphocytic leukaemia, adult T cell leukaemia-lymphoma, and Sézary syndrome) and partial remission in two others. Unmaintained complete remission lasting more than one year was seen in three patients. Responses were obtained only in patients with CD4+,CD8-membrane markers (seven out of 10), and no responses were recorded in any of the nine patients with a different phenotype. In this series remission appeared to correlate with the membrane phenotype of the neoplastic cell and not with the cytopathological diagnosis. Future studies should establish the biochemical basis for the greater sensitivity of CD4+ lymphoid cells to deoxycoformycin.

Intensive cytoreductive therapy followed by autologous bone marrow transplantation for patients with hematologic malignancies or solid tumors.

Fifty patients were studied. Twenty patients with non-Hodgkin's lymphomas (NHL) of high-grade malignancy and 21 patients with acute leukemia (AL) were treated with high-dose cyclophosphamide and total body irradiation, and three patients with Hodgkin's disease (HD) and six patients with solid tumors were treated with high-dose cyclophosphamide and VP16-213. Those procedures were followed by autologous bone marrow transplantation (ABMT). All patients had received conventional chemo(radio)therapy before the ABMT procedure. Although remissions were obtained in patients with cytotoxic drug-resistant diseases (lymphomas and solid tumors), none has become a long-term survivor, as occurred also in patients with solid tumors in partial remission (PR). Two of five patients with NHL in PR at the time of ABMT have become long-term disease-free survivors (28+, 56+ months). Ten patients with NHL were treated in complete remission (CR) and seven are in unmaintained CR; four with long follow-up (14+ to 59+ months). All patients with AL were treated in CR; two patients received ABMT in second CR, and both relapsed. Ten of nineteen patients in first CR relapsed; eight are alive in CR, five with long follow-up. Four deaths were therapy-related, all were patients in poor clinical condition. Intensive cytoreductive therapy followed by ABMT can produce prolonged disease-free survival (and probably cure) in a fair number of patients with poor risk NHL in CR and PR and probably also in patients with acute myeloblastic leukemia in first CR. This procedure was not successful in achieving long-term disease-free survival in patients with refractory lymphomas or solid tumors.

Enhancement of delayed cutaneous hypersensitivity by oral administration of RU 41740 (Biostim ®) in lymphoma patients — A randomized double blind multicentric trial

RU 41740 (Biostim) is a glycoprotein extract from Klebsiella pneumoniae with immunostimulating properties in animal studies and in in vitro assays of human leukocyte functions. The present randomized double blind phase II trial showed that RU 41740 significantly (P less than 0.05, Mann & Whitney test) enhanced delayed cutaneous hypersensitivity to seven recall antigens (Multitest system) in lymphoma patients in unmaintained complete remission when given orally for 14 days at a daily dose of 8 mg, and compared to placebo. Daily doses of 2 and 32 mg were uneffective.

Allogeneic marrow transplantation in the treatment of MOPP-resistant Hodgkin's disease.

Eight patients with disseminated Hodgkin's disease resistant to MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) chemotherapy were treated with high-dose chemoradiotherapy and marrow transplantation from an HLA-identical sibling. Two patients remain alive in unmaintained complete remission (CR) at 38 and 39 months after transplant. In the other six patients, reasons for failure included relapse of lymphoma (two patients), or death due to complications of the transplant procedure, including Legionnaire's disease, disseminated zoster, graft-v-host disease, and aspiration pneumonia secondary to severe mucositis. These results demonstrate that some patients with MOPP-resistant Hodgkin's disease can obtain prolonged CR following intensive chemoradiotherapy and allogeneic marrow transplantation.

A Clinical Trial of Anti-Idiotype Therapy for B Cell Malignancy

Eleven patients with B lymphocytic malignancy were treated with mouse monoclonal anti-idiotype antibodies. All but one of the patients in this study had received extensive prior treatment with conventional lymphoma therapy. All antibodies were prepared against, and uniquely reactive with, the patient's own tumor. Ten patients were treated with a single antibody, but one patient received three antibodies concurrently. The treatment protocol initially used an escalating dose schedule that was intended to evaluate toxicity, pharmacokinetics and, eventually, to achieve appreciable levels of free mouse antibody in the circulation. The last two patients received substantial initial doses. Tumor sampling was performed before and during therapy to evaluate tissue penetration by antibody. None of the patients had serum paraproteins by routine clinical testing, but six had idiotype protein detectable by a sensitive immunoassay at levels greater than 1 microgram/mL, two of which were greater than 200 micrograms/mL. Plasmapheresis was capable of reducing these levels temporarily. However, the presence of serum idiotype increased the requirement for mouse antibody to achieve tumor penetration. Another obstacle to treatment was immune response to mouse Ig, which occurred in five of the 11 patients. Once an immune response had begun, further infusions of antibody were not capable of reaching the tumor or inducing tumor regression and were associated with toxicity. Our initial patient remains in an unmaintained complete remission 42 months after receiving antibody. Five of ten additional patients have had objective remissions that were also clinically significant. However, these remissions were not complete and were of relatively short duration. This therapy shows promise as an alternative modality for the treatment of B cell malignancy. Further study will be needed to determine the mechanisms of the antitumor effect and to improve the clinical results.