Preparation and radiolabeling of a lyophilized (kit) formulation of DOTA-rituximab with 90Y and 111In for domestic radioimmunotherapy and radioscintigraphy of Non-Hodgkin’s Lymphoma

Background

On the basis of results of our previous investigations on ⁹⁰Y-DTPA-rituximab and in order to fulfil national demands to radioimmunoconjugates for radioscintigraphy and radioimmunotherapy of Non-Hodgkin’s Lymphoma (NHL), preparation and radiolabeling of a lyophilized formulation (kit) of DOTA-rituximab with ¹¹¹In and ⁹⁰Y was investigated.

Methods

¹¹¹In and ⁹⁰Y with high radiochemical and radionuclide purity were prepared by ¹¹²Cd (p,2n)¹¹¹In nuclear reaction and a locally developed ⁹⁰Sr/⁹⁰Y generator, respectively. DOTA-rituximab immunoconjugates were prepared by the reaction of solutions of p-SCN-Bz-DOTA and rituximab in carbonate buffer (pH = 9.5) and the number of DOTA per molecule of conjugates were determined by transchelation reaction between DOTA and arsenaso yttrium(III) complex. DOTA-rituximab immunoconjugates were labeled with ¹¹¹In and ⁹⁰Y and radioimmunoconjugates were checked for radiochemical purity by chromatography methods and for immunoreactivity by cell-binding assay using Raji cell line. The stability of radiolabeled conjugate with the approximate number of 7 DOTA molecules per one rituximab molecule which was prepared in moderate yield and showed moderate immunoreactivity, compared to two other prepared radioimmunoconjugates, was determined at different time intervals and against EDTA and human serum by chromatography methods and reducing SDS-polyacrylamide gel electrophoresis, respectively. The biodistribution of the selected radioimmunoconjugate in rats was determined by measurement of the radioactivity of different organs after sacrificing the animals by ether asphyxiation.

Results

The radioimmunoconjugate with approximate DOTA/rituximab molar ratio of 7 showed stability after 24 h at room temperature, after 96 h at 4°C, as the lyophilized formulation after six months storage and against EDTA and human serum. This radioimmunoconjugate had a biodistribution profile similar to that of ⁹⁰Y-ibritumomab, which is approved by FDA for radioimmunotherapy of NHL, and showed low brain and lung uptakes and low yttrium deposition into bone.

Conclusion

Findings of this study suggest that further investigations may result in a lyophilized (kit) formulation of DOTA-rituximab which could be easily radiolabeled with ⁹⁰Y and ¹¹¹In in order to be used for radioimmunotherapy and radioscintigraphy of B-cell lymphoma in Iran.     

利妥昔单抗联合CHOP方案治疗非霍奇金淋巴瘤的效果观察

目的探讨利妥昔单抗联合CHOP方案治疗非霍奇金淋巴瘤的临床效果。方法选择本院2012年5月~2014年5月收治的非霍奇金淋巴瘤患者30例,将其随机分为观察组和对照组各15例。对照组患者采用CHOP方案进行治疗,观察组患者在对照组治疗的基础加用利妥昔单抗联合治疗,比较两组的临床疗效。结果观察组治疗有效率为80.0%,高于对照组的60.0%,差异有统计学意义(P<0.05);观察组不良反应发生率为53.3%,对照组不良反应发生率为60.0%,差异无统计学意义(P>0.05)。结论利妥昔单抗联合CHOP方案治疗非霍奇金淋巴瘤效果显著,值得临床推广。     

Six month assessment of low dose rituximab in the treatment of rheumatoid arthritis during coronavirus disease 2019 (COVID-19) pandemic

Aim of the workTo evaluate the 6-month treatment responses to low dose rituximab (LDR) compared to standard dose rituximab (SDR) in rheumatoid arthritis (RA) patients whose treatments were disrupted due to the pandemic with increased disease activity and to examine the effect of LDR treatment on serum immunoglobulin (Ig) levels.Patients and methodsRecords were retrospectively analysed for 80 patients on SDR not admitted to the hospital due to fear of infection during pandemic, with increased disease activity and were resumed on LDR (500 mg intravenous RTX-infusion twice with 15 days intervals, and repeated for the second time in all patients after 6 months). Disease activity score (DAS-28) values were obtained. The Ig levels of the patients before and after rituximab treatment were calculated.ResultsThe mean age of patients was 55.1 ± 13.1 years. They were 46 (57.5%) female and 34 (42.5%) male (F:M 1.4:1) with median disease duration of 13 (0.5–50) years. After the second dose of LDR, there was a significant decrease in the disease activity DAS28 (6.5 ± 1.01 to 3.2 ± 1.2, p < 0.0001) and acute phase reactants with a tendency to decrease in Ig levels. After LDR, 6 (7.5%) patients developed COVID-19 infection that did not require hospitalization. There was no difference between the Ig levels of patients with and without COVID-19 infection.ConclusionsLDR is an effective treatment option in the treatment of RA. In our study, none of our patients developed severe COVID-19 infection requiring hospitalization, and LDR may be preferred during the COVID-19 pandemic period.     

Monoclonal antibody therapy for B-cell lymphoma

Treatment strategies and outcomes for patients with non-Hodgkin's lymphoma (NHL) are undergoing rapid and important evolution. We have recently witnessed the advent of novel targeted therapies, such as gene therapies, active immunotherapies, antisense therapies, new small molecules and biologicals, and monoclonal antibodies (MoAbs). The first MoAb approved for the treatment of cancer, rituximab, was approved in 1997 and has been rapidly incorporated into treatment regimens for NHL. In a randomized trial in combination with CHOP chemotherapy (cyclophosphamide, hydroxydaunomycin, vincristine, and prednisone), rituximab showed superiority to CHOP for patients with diffuse large cell NHL (DLCL).The rituximab + CHOP combination has become the gold standard for frontline therapy for DLCL and has shown significant activity in the management of follicular NHL. In February 2002, the first radioimmunotherapeutic agent for the treatment of cancer, ibritumomab tiuxetan (Zevalin), was approved. Ibritumomab tiuxetan, an yttrium-labeled antibody used in conjunction with rituximab, has significant activity in follicular and transformed NHL. Use of rituximab has proved that antibodies are safe and active even as single agents. The results have helped dispel the negativity and biases resulting from many years of disappointing results in this important area of research. Results with rituximab have opened the doors to continued research and have provided the impetus necessary for renewed enthusiasm and optimism in continuing the search for curative regimens for patients with NHL.     

Expression of CD20 in B Cell Precursor Acute Lymphoblastic Leukemia

CD20 is a B cell differentiation antigen with variable expression in B cell precursor acute lymphoblastic leukemia (BCP-ALL). The significance of CD20 expression has been evaluated in BCP-ALL with conflicting results. There is paucity of data regarding CD 20 expression in BCP-ALL in Indian patients. We retrospectively analyzed 100 patients of BCP-ALL for CD20 expression. CD20 positivity was defined as expression of CD20 to be more than or equal to 20 % in the blast population. 62 % patients expressed CD20 while 38 % patients were negative for CD20. The positivity ranged from negative to dim (35.5 % patients), moderately bright (19.3 % patients) to bright (45.2 % patients). Additional prospective studies are needed to determine the optimal use of rituximab in treatment of CD20-positive BCP-ALL.     

Interleukin‐10 producing‐B cells and their association with responsiveness to rituximab in myasthenia gravis

Introduction: A subset of regulatory B cells in humans and mice has been defined functionally by their ability to produce interleukin (IL)‐10. We characterized IL‐10‐producing B (B10) cells in myasthenia gravis (MG) patients and correlated them with disease activity and responsiveness to rituximab therapy. Methods: Frequencies of B10 cells from MG patients and healthy controls were monitored by fluorescence‐activated cell sorting (FACS). Results: MG patients had fewer B10 cells than controls, which was associated with more severe disease status. Moreover, patients who responded well to rituximab therapy exhibited rapid repopulation of B10 cells, whereas in patients who did not respond well to rituximab, B10 cell repopulation was delayed. The kinetics of B10 cells were related to the responsiveness to rituximab in MG. Conclusions: We have characterized a specific subset of B10 cells in MG patients which may serve as a marker for disease activity and responsiveness to immune therapy. Muscle Nerve 49:487–494, 2014     

Comparison of low fixed dose versus standard-dose rituximab to treat thrombotic thrombocytopenic purpura in the acute phase and preemptively during remission

The standard dose of rituximab used in B-cell hematological malignancies, 375 mg/m² weekly, may be excessive for autoimmune conditions. Successful use of a low, fixed dose of 100−200 mg of rituximab, weekly for 4 weeks, has been reported in the literature in the treatment of autoimmune thrombotic thrombocytopenic purpura (aTTP). We retrospectively analyzed our rituximab data in aTTP over a 13-year-period for 39 patients, with the aim of comparing response and outcomes with a standard lymphoma-dose course versus a low fixed 100 mg-dose course. Compared to the standard dose (17 patients, 17 courses of 4 infusions), our patients who received a low dose (8 patients, 9 courses of 4 infusions) had a possibly lower baseline risk but did achieve a similar time to remission and number of plasma exchange procedures to remission. Preemptive low-dose courses for ADAMTS13 activity <50 % during remission (6 patients, 10 courses of 4 infusions) achieved a median peak ADAMTS13 activity of 99 %, in a median of 1 month, with no clinical relapses. Our results provide additional evidence for the efficacy of low-dose rituximab, with the benefit of much lower cost, less infusion time, and theoretically lower risk of toxicity.     

Anti-CD20 Monoclonal Antibody (Rituximab) for Therapy of Mediastinal CD20-Positive Large B-Cell Non-Hodgkin Lymphoma with a Local Tumor Extension into the Lung of a 10-Year-Old Girl

Intravenous therapy with the anti-CD20 antibody Rituximab has been recently approved for the treatment of CD20 positive non-Hodgkin's lymphoma (NHL) in adults but not in children. The authors present the benefits of its application for mediastinal NHL CD 20+ with a local extension into the lung of a 10-year-old-girl. Receiving the chemotherapy according to study NHL-BFM-95 for high-risk lymphoma the girl did not reach complete remission. Before the last chemotherapy block was started, a computed tomography scan of the thorax showed residue in the right lung. Twenty-five days after the last chemotherapy she received Rituximab at a dose of 375 mg/m 2 by intravenous infusion once a week for a total of four doses without the adverse reactions. Complete remission was achieved. The patient was high risk with lung involvement of lymphoma suggesting a pure prognosis. The results suggest that Rituximab may improve the outcome in high-risk patients and appeared to be safe and effective in children also.     

Transient increases in anti-aquaporin-4 antibody titers following rituximab treatment in neuromyelitis optica, in association with elevated serum BAFF levels

Rituximab is increasingly used for prevention of relapses of neuromyelitis optica (NMO), a condition that is highly associated with serum anti-aquaporin-4 (AQP4) antibodies. However, B-cell depletion also induces systemic B-cell activating factor (BAFF), which may promote antibody production. We collected serial serum samples from a total of seven patients with NMO prior to, and following, treatment with rituximab. The samples were analyzed for anti-AQP4 antibody titer using a cell-based assay and serum BAFF levels were measured on available samples by standard enzyme-linked immunosorbent assay. Anti-AQP4 antibody levels decreased after 4 weeks to 12 weeks from the first injection of rituximab, but they increased transiently in several patients at 2 weeks after the first injection, in association with a parallel increase in serum BAFF levels. Although anti-AQP4 antibodies appear to decrease overall following rituximab treatment, our findings raise concern over the potential for an early BAFF-mediated worsening of patients with NMO receiving rituximab.