Emmanouilides, Christos

Abstract Radioimmunotherapy (RIT) is a therapeutic modality indicated for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed non-Hodgkin’s lymphoma (NHL), where the mechanism of action involves the intrinsic activity of the monoclonal antibody and the cytotoxic effects of radiation. The primary toxicity is a late-occurring, transient, and reversible myelosuppression. Because of concerns regarding the long-term effects of radiation on the bone marrow, we investigated the incidence of treatment-related myelodysplastic syndrome (t-MDS) and treatment-related acute myelogenous leukemia (t-AML) after ibritumomab tiuxetan RIT. A total of 746 patients with NHL were treated with the ibritumomab tiuxetan regimen in registration and compassionate-use trials between 1996 and 2002. Patients had a median age of 61 years (range, 24–87) and had received a median of 3 prior therapies (range, 0–9+). The crude incidence of t-MDS or t-AML was 2.3% (17/746), with an incidence of 4.7% (10/211) in patients enrolled in registration trials and of only 1.3% (7/535) in patients included in the compassionate-use trial, with a median follow-up of 5.7 and 3.5 years, respectively. These malignancies were documented at a median of 5.6 years (range, 1.2–13.9) after the diagnosis of NHL and 1.5 years (range, 0.1–5.8) after RIT. The annualized rates were 0.3% (95% CI, 0.2%–0.4%) a year after the diagnosis of NHL and 0.7% (95% CI, 0.4%–1.0%) a year after RIT. Cox multivariate regression analysis found that previous treatment with a purine nucleoside analog was a significant risk factor for t-MDS or t-AML (hazard ratio, 3.9 [95% CI, 1.5–10.4]; P = .006). All patients in whom t-MDS or t-AML developed and in whom cytogenetic data were available (n = 15) had multiple cytogenetic aberrations, commonly of chromosomes 5 and 7, suggesting an association with previous exposure to chemotherapy. There were documented bone marrow cytogenetic abnormalities before treatment in 2 patients who developed t-MDS or t-AML. These data suggest that the annualized incidence of t-MDS or t-AML following ibritumomab tiuxetan RIT is consistent with that expected on the basis of the patients’ history of treatment for NHL. Cytogenetic testing before administration of RIT may identify existing chromosomal abnormalities in previously treated patients, particularly in those who have been treated with alkylating agents and/or purine nucleoside analogs and who are thereby at a higher risk for t-MDS or t-AML.

Abstract Background: As the first radiolabled monoclonal antibody approved for the treatment for the treatment of cancer, yttrium 90 (90Y) ibritumomab tiuxetan (Zevalin®) achieves both high response rates and durable remissions in patients with relapsed or refractory, low-grade, follicular, or transformed B-cell NHL. Because of the stability of 90Y ibritumomab tiuxetan and its favorable pharmacokinetic profile (ie, predictable urinary clearance and absence of dehalogenation), dosing is based on patient weight and platelet counts. Yttrium 90 ibritumomab tiuxetan is typically delivered at a dose of 0.4 mCi/kg (in patients with platelets >150,000/mm3) or 0.3 mCi/kg (in patients with platelets ≤150,000/mm3) to a maximum recommended dose (MRD) of 32 mCi. However, patients >80 kg with platelet counts exceeding 150,000/mm3 may receive a lower drug concentration (ie, <0.4 mCi/kg 90Y) as a result of dose capping. We evaluated whether the 32 mCi dose cap influences the safety or efficacy of ibritumomab tiuxetan therapy in patients >80 kg. Methods: Efficacy and safety data were collected for patients from 3 registrational trials that received either 0.4 mCi/kg 90Y (patients ≤80 kg) or 32 mCi 90Y (patients >80 kg). Results: Clinical responses in 170 patients were evaluated. Patients ≤80 kg (n = 103) had a median weight of 70 kg (range, 45–80 kg) versus a median weight of 95 kg (range, 81–159) for patients >80 kg (n = 67). Gender (41% M vs 73% M, respectively; P <.01) was the only significantly different baseline characteristic between the ≤80 kg and >80 kg groups. Similar efficacy and safety results were reported for both subsets of patients. Overall response rates of 79% and 70% were observed for patients ≤80 kg and >80 kg, respectively (P =.27); and no significant differences were seen in complete response rates (28% vs 34%, respectively; P =.40). Median TTP (8.9 months vs 9.5 months; P =.53) and median DR (8.5 months vs 11.5 months; P =.34) were equivalent between the 2 weight-based groups. In addition, there were no statistically significant differences in safety measures including grade 3/4 nonhematologic adverse events, neutropenia, thrombocytopenia, or anemia. Conclusions: As a consequence of dose capping at an MRD of 32 mCi, 39% of patients received a lower dose/kg of 90Y ibritumomab tiuxetan. However, despite the difference in dose administered on a unit of body weight basis, the efficacy and safety results were similar between patients ≤80 kg and >80 kg. We conclude that the 32 mCi dose cap does not influence the efficacy or safety profile of 90Y ibritumomab tiuxetan for patients >80 kg.

Abstract Background: Radioimmunotherapy (RIT) is an emerging clinical treatment option for patients with non-Hodgkin’s lymphoma (NHL). Yttrium 90 (90Y) ibritumomab tiuxetan (Zevalin®) RIT was approved by the FDA in February 2002 for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed B-cell NHL, including patients with rituximab-refractory follicular NHL. In 4 registrational trials of 90Y ibritumomab tiuxetan conducted between 1996 and 1999, 211 patients with B-cell NHL were treated. Of these 211 patients, 153 patients (73%) had follicular lymphoma (FL). With ongoing follow-up, long-term durable responses have been observed, but until now have not been more fully characterized. Methods: Responding patients with time to progression (TTP) of ≥12 months were identified and characterized as long-term responding (LTR) patients. Results: In the 4 registrational trials, 78 of the 211 patients (37%) were identified as LTR patients. Characteristics of these LTR patients were as follows: median age 58 years (range, 24 to 80), 44% >60 years old, 55% male, 76% with follicular lymphoma, and 41% with lymphomatous marrow involvement. LTR patients had a median of 2 prior regimens (range, 1–9): 59% had ≥2 prior therapies, 33% had ≥3 prior therapies, and 37% had no response to their last prior therapy. Thirty percent of LTR patients had bulky disease (tumor size >5 cm) and 83% had stage III/IV disease. At the time of this analysis, the median duration of response (DR) and TTP for LTR patients were 28 months (range 11–80) and 29 months (range 12–82), respectively, with a median follow-up of 50 months (range 13–82). The median DR to the last prior therapy for LTR patients was 12 months. The complete response rate (confirmed [CR] and unconfirmed [CRu]) among LTR patients was 65%, and the median DR and TTP were 29 and 31 months, respectively, for CR/CRu patients. In ongoing responders the median DR is 52 months (range 48–80). Among the 153 patients with FL, 59 (39%) were identified as LTR patients. Compared to the overall LTR patients, LTR patients with FL had similar disease characteristics, DR, TTP, and CR/CRu rates. Conclusions: Ongoing follow-up indicates that 90Y ibritumomab tiuxetan frequently produces durable long-term responses (TTP ≥12 months) in patients with relapsed or refractory B-cell NHL. Failure to respond to the therapy immediately prior to treatment with 90Y ibritumomab tiuxetan does not appear to affect the ability to achieve long-term responses with 90Y ibritumomab tiuxetan. Durable long-term responses were achieved in 37% of all patients and 39% of patients with FL treated in 4 registrational trials of 90Y ibritumomab tiuxetan at 30 centers in the US. Of these LTR patients, a high proportion were >60 years old and had received ≥3 prior therapies.

PURPOSE: Yttrium-90 ibritumomab tiuxetan (IDEC-Y2B8) is a murine immunoglobulin G1 kappa monoclonal antibody that covalently binds MX-DTPA (tiuxetan), which chelates the radioisotope yttrium-90. The antibody targets CD20, a B-lymphocyte antigen. A multicenter phase I/II trial was conducted to compare two doses of unlabeled rituximab given before radiolabeled antibody, to determine the maximum-tolerated single dose of IDEC-Y2B8 that could be administered without stem-cell support, and to evaluate safety and efficacy.PATIENTS AND METHODS: Eligible patients had relapsed or refractory (two prior regimens or anthracycline if low-grade disease) CD20+B-cell low-grade, intermediate-grade, or mantle-cell non-Hodgkin's lymphoma (NHL). There was no limit on bulky disease, and 59% had at least one mass ≥ 5 cm.RESULTS: The maximum-tolerated dose was 0.4 mCi/kg IDEC-Y2B8 (0.3 mCi/kg for patients with baseline platelet counts 100 to 149,000/μL). The overall response rate for the intent-to-treat population (n = 51) was 67% (26% complete response [CR]; 41% partial response [PR]); for low-grade disease (n = 34), 82% (26% CR; 56% PR); for intermediate-grade disease (n = 14), 43%; and for mantle-cell disease (n = 3), 0%. Responses occurred in patients with bulky disease (≥ 7 cm; 41%) and splenomegaly (50%). Kaplan-Meier estimate of time to disease progression in responders and duration of response is 12.9+ months and 11.7+ months, respectively. Adverse events were primarily hematologic and correlated with baseline extent of marrow involvement with NHL and baseline platelet count. One patient (2%) developed an anti-antibody response (human antichimeric antibody/human antimouse antibody).CONCLUSION: These phase I/II data demonstrate that IDEC-Y2B8 radioimmunotherapy is a safe and effective alternative for outpatient therapy of patients with relapsed or refractory NHL. A phase III study is ongoing.

Purpose To investigate the incidence of treatment-related myelodysplastic syndrome (t-MDS) and treatment-related acute myelogenous leukemia (t-AML) after treatment with ibritumomab tiuxetan radioimmunotherapy. Patients and Methods Analysis of the incidence of t-MDS and t-AML in 746 patients with non-Hodgkin's lymphoma (NHL) treated with the ibritumomab tiuxetan regimen in registration and compassionate-use trials between 1996 and 2002. Results Nineteen patients (2.5%) developed t-MDS or t-AML at a median follow-up of 4.4 years (range, 0 to 9.3). These malignancies were diagnosed at a median of 5.6 years (range, 1.4 to 13.9) after the diagnosis of NHL and 1.9 years (range, 0.4 to 6.3) after radioimmunotherapy. The annualized rates were 0.3% per year after the diagnosis of NHL and 0.7% per year after treatment. Most patients with t-MDS or t-AML had multiple cytogenetic aberrations, commonly on chromosomes 5 and 7, suggesting an association with previous exposure to chemotherapy. Conclusion Analysis of data from patients in registration and compassionate-use trials suggests that the annualized incidences of t-MDS and t-AML are consistent with that expected in patients with NHL who have had extensive previous chemotherapy treatment and do not appear to be increased after treatment with the ibritumomab tiuxetan regimen. Cytogenetic testing before treatment with radioimmunotherapy may identify existing chromosomal abnormalities in previously treated patients, particularly those who have been treated with alkylating agents and purine nucleoside analogs and would be at higher risk for t-MDS or t-AML.

PurposeThis multicenter, dose-escalation study evaluates the safety, pharmacokinetics, and efficacy of galiximab (anti-CD80 monoclonal antibody) in patients with relapsed or refractory follicular lymphoma.Patients and MethodsPatients had follicular lymphoma that had relapsed or failed to respond to primary therapy; the majority (90%) presented with stage III or IV disease. Four weekly intravenous infusions of galiximab were administered at doses of 125, 250, 375, or 500 mg/m2.ResultsThirty-seven patients received galiximab treatment and were evaluated for safety; 35 were assessable for response. Antibody infusions were safe and well tolerated with no dose-limiting toxicities. A total of 22 (60%) of 37 patients experienced adverse events related to galiximab. All but one of the events were grade 1 or 2; the most common were fatigue, nausea, and headache. Cytopenias were rare; only one patient experienced anemia and febrile neutropenia, which were unrelated to galiximab and resolved after treatment. No patient developed antigaliximab antibody formation. The mean serum half-life ranged from 13 to 24 days. The overall response rate was 11% (two complete responses and two partial responses). Time to best response was delayed (months 3, 6, 9, and 12). Twelve patients (34%) maintained stable disease. Nearly half of all patients (49%) had a decrease in indicator lesions. Two responders remain on study without progression (22 and 24.4 months).ConclusionThe favorable safety profile of galiximab and evidence of single-agent biologic activity and dose-dependent pharmacokinetics support further evaluation of galiximab as a treatment for follicular lymphoma, possibly in combination with other lymphoma therapies.

Abstract We previously demonstrated that yttrium-90 (Y-90) ibritumomab tiuxetan (Zevalin) radioimmunotherapy (RIT) was safe and effective for relapsed or refractory CD20+, B-cell, non-Hodgkin lymphoma (NHL). We now provide long-term follow-up data in responding patients based on International Workshop Response Criteria. Complete (CR), CR unconfirmed (CRu), and partial response (PR) rates were 29%, 22%, and 22%, respectively (overall response rate 73%, 51% in CR/CRu). Mean time to progression (TTP) and duration of response (DR) in responders were 12.6 months and 11.7 months, respectively. At the maximum tolerated dose (0.4 mCi/kg [14.8 MBq/kg]), TTP and DR in complete responders (CR/CRu) were 28.3 and 27.5 months, respectively. Nine patients (24% of responding patients) had a TTP of more than 3 years. Long-term responders (> 5 years) have been identified. Ibritumomab tiuxetan produces durable responses in patients with indolent and diffuse large B-cell lymphoma. (Blood. 2004;103:4429-4431)