Radioimmunotherapy for Non-Hodgkin's Lymphoma

90Yttrium Ibritumomab Tiuxetan (Zevalin) for the Treatment of Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Report of 5 Cases

Radioimmunotherapy (RIT) with radio-labeled monoclonal antibodies to CD20 produces a high response rate in patients with low-grade B-cell lymphomas. The use of this modality in patients with chronic lymphocytic leukemia (CLL) has been sporadic in clinical trials and was hampered by the extensive marrow involvement seen commonly in patients with CLL, which would produce a high risk for marrow aplasia after treatment with RIT. Herein, we report our experience with RIT in 5 patients with CLL or SLL showing short-lived responses and significant myelosuppression. After 90Y-ibritumomab tiuxetan treatment, the median time to relapse was 65 days, and no cases of MDS or AML were observed during follow-up. All patients experienced grade ≥3 thrombocytopenia and neutropenia, with median durations of 39.5 days and 107 days, respectively.

Implications of physics, chemistry and biology for dosimetry calculations using theranostic pairs

Theranostics is an emerging paradigm that combines imaging and therapy in order to personalize patient treatment. In nuclear medicine, this is achieved by using radiopharmaceuticals that target identical molecular targets for both imaging (using emitted gamma rays) and radiopharmaceutical therapy (using emitted beta, alpha or Auger-electron particles) for the treatment of various diseases, such as cancer. If the therapeutic radiopharmaceutical cannot be imaged quantitatively, a “theranostic pair” imaging surrogate can be used to predict the absorbed radiation doses from the therapeutic radiopharmaceutical. However, theranostic dosimetry assumes that the pharmacokinetics and biodistributions of both radiopharmaceuticals in the pair are identical or very similar, an assumption that still requires further validation for many theranostic pairs. In this review, we consider both same-element and different-element theranostic pairs and attempt to determine if factors exist which may cause inaccurate dose extrapolations in theranostic dosimetry, either intrinsic (e.g. chemical differences) or extrinsic (e.g. injecting different amounts of each radiopharmaceutical) to the radiopharmaceuticals. We discuss the basis behind theranostic dosimetry and present common theranostic pairs and their therapeutic applications in oncology. We investigate general factors that could create alterations in the behavior of the radiopharmaceuticals or the quantitative accuracy of imaging them. Finally, we attempt to determine if there is evidence showing some specific pairs as suitable for theranostic dosimetry. We show that there are a variety of intrinsic and extrinsic factors which can significantly alter the behavior among pairs of radiopharmaceuticals, even if they belong to the same chemical element. More research is needed to determine the impact of these factors on theranostic dosimetry estimates and on patient outcomes, and how to correctly account for them.

Inhibition of HIF-1α by Atorvastatin During 131I-RTX Therapy in Burkitt's Lymphoma Model

BACKGROUNDS

Radioimmunotherapy (RIT) serves as a targeted therapy for non-Hodgkin lymphomas (NHL). Although HIF(Hypoxia-inducible factors)-1α is an important biomarker during radiation therapy, its role in NHL is unclear. Atorvastatin (ATV) is used as a combination drug for chemotherapy.

METHODS

We investigated whether ATV downregulated tumor radio-resistance and enhanced the anticancer effect of 131I-RTX (rituximab) in Raji xenograft mouse models. First, the increased uptake and enhanced therapeutic effect of 131I-RTX by ATV was confirmed using molecular imaging in Raji xenograft subcutaneous model and orthotropic model with SPECT and IVIS images. Second, we examined the profile of differentially expressed miRNAs using miRNA array.

RESULTS

We found that miR-346 inhibited HIF-1α/VEGF (Vascular endothelial growth factor) during ATV combination therapy with 131I-RTX. The underlying mechanism of ATV involved induction of anti-angiogenesis and radiosensitivity by downregulating HIF-1α in Raji cells.

CONCLUSION

Our findings suggested that combination therapy with ATV and 131I-RTX is a promising strategy for enhancing the potency of 131I-RTX therapy in poorly responding patients and those with radio-resistance.

NEMA NU 2-2007 performance characteristics of GE Signa integrated PET/MR for different PET isotopes

BACKGROUND

Fully integrated PET/MR systems are being used frequently in clinical research and routine. National Electrical Manufacturers Association (NEMA) characterization of these systems is generally done with ¹⁸F which is clinically the most relevant PET isotope. However, other PET isotopes, such as ⁶⁸Ga and ⁹⁰Y, are gaining clinical importance as they are of specific interest for oncological applications and for follow-up of ⁹⁰Y-based radionuclide therapy. These isotopes have a complex decay scheme with a variety of prompt gammas in coincidence. ⁶⁸Ga and ⁹⁰Y have higher positron energy and, because of the larger positron range, there may be interference with the magnetic field of the MR compared to ¹⁸F. Therefore, it is relevant to determine the performance of PET/MR for these clinically relevant and commercially available isotopes.

METHODS

NEMA NU 2-2007 performance measurements were performed for characterizing the spatial resolution, sensitivity, image quality, and the accuracy of attenuation and scatter corrections for ¹⁸F, ⁶⁸Ga, and ⁹⁰Y. Scatter fraction and noise equivalent count rate (NECR) tests were performed using ¹⁸F and ⁶⁸Ga. All phantom data were acquired on the GE Signa integrated PET/MR system, installed in UZ Leuven, Belgium.

RESULTS

¹⁸F, ⁶⁸Ga, and ⁹⁰Y NEMA performance tests resulted in substantially different system characteristics. In comparison with ¹⁸F, the spatial resolution is about 1 mm larger in the axial direction for ⁶⁸Ga and no significative effect was found for ⁹⁰Y. The impact of this lower resolution is also visible in the recovery coefficients of the smallest spheres of ⁶⁸Ga in image quality measurements, where clearly lower values are obtained. For ⁹⁰Y, the low number of counts leads to a large variability in the image quality measurements. The primary factor for the sensitivity change is the scale factor related to the positron emission fraction. There is also an impact on the peak NECR, which is lower for ⁶⁸Ga than for ¹⁸F and appears at higher activities.

CONCLUSIONS

The system performance of GE Signa integrated PET/MR was substantially different, in terms of NEMA spatial resolution, image quality, and NECR for ⁶⁸Ga and ⁹⁰Y compared to ¹⁸F. But these differences are compensated by the PET/MR scanner technologies and reconstructions methods.

Radioimmunotherapy as a Novel Approach in HIV, Bacterial, and Fungal Infectious Diseases

In the past several decades, many antimicrobial agents have been used in treating different fungal, bacterial, and viral infections. However, these agents have faced challenges such as pronounced side-effect profiles and pathogen resistance. In addition, a cure for many chronic infections such as human immunodeficiency virus (HIV) has not been achieved, and the incidence of opportunistic infections in immunocompromised patients has increased significantly in the past decades. Therefore, an alternative strategy for combating these infections is needed. Radioimmunotherapy (RIT) has been proposed to be a valuable tool in the management of such infections. The side-effects associated with RIT are minimal as the targeted antigens are only expressed on microbial or infected cells. RIT demonstrated impressive potency in eradicating pathogens in animal models and patient samples. Cryptococcus neoformans, HIV, and Bacillus anthracis are few examples of infections for which RIT has been an effective treatment using radionuclides such as bismuth-213 (²¹³Bi) or rhenium-188 (¹⁸⁸Re).

Novel agents for the treatment of childhood leukemia: an update

Achieving lower morbidity and higher survival rates in the treatment of childhood leukemia has been a paradigm of success in modern oncology. However, serious long-term health complications occur in very large populations of childhood leukemia survivors, in the case of both acute lymphoid leukemia and acute myeloid leukemia (AML). Additionally, 15% of acute lymphoid leukemia patients have treatment failures, and rates are even higher in childhood AML. In the last few decades, as a result of well-tested experiments that statistically analyzed treatment cohorts, new agents have emerged as alternatives or supplements to established treatments, in which high survival and/or less morbidity were observed. This review provides an overview of better practice in the treatment of childhood leukemia.

Safety and efficacy of radioimmunotherapy (RIT) in treatment of non-Hodgkin's lymphoma in the community setting

INTRODUCTION

Radioimmunotherapy (RIT) is a unique therapeutic modality that combines biologic and radiolytic mechanisms to induce tumor kill. RIT is underutilized in the community outpatient setting.

METHODS

This is an institutional review of patients treated with RIT at St. John Hospital and Medical Center (SJH&MC) 2003-2011. RIT agents were dosed according to recommended guidelines. Response was assessed using the Revised Response Criteria for Malignant Lymphoma and toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events. The primary aim was to assess overall response rate (ORR) and overall survival (OS). The secondary aim was to assess the impact of variable host and disease factors on the ORR to RIT and OS.

RESULTS

Forty-eight patients were treated with RIT within the specified period at SJH&MC; of which 52% with follicular lymphoma (FL) and 46% with diffuse large B cell lymphoma (DLBCL). The majority of patients had relapsed or refractory disease (98%). Median duration of follow-up was 17 months. The ORR was 73% with 44% complete remission (CR) rate and OS of 48 months. The ORR was 79% with 58% CR rate and OS of 82 months among FL patients. Among DLBCL patients, the ORR was 65% with 30% CR rate and OS of 39 months. Response to last therapy before RIT was the only significant predictor of response to RIT and a significant predictor of OS in multivariate analyses. Prior exposure to EBRT did not predict response or survival in multivariate analyses. Toxicity was manageable and predominantly hematologic.

CONCLUSIONS

RIT is effective and feasible for use in the community outpatient setting.

ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE

Patients with B-cell NHL can safely receive RIT close to home. With some coordination of effort, it is not difficult for community-based cancer centers to implement this treatment modality.

EphA2 Is a Therapy Target in EphA2-Positive Leukemias but Is Not Essential for Normal Hematopoiesis or Leukemia

Members of the Eph family of receptor tyrosine kinases and their membrane bound ephrin ligands have been shown to play critical roles in many developmental processes and more recently have been implicated in both normal and pathological processes in post-embryonic tissues. In particular, expression studies of Eph receptors and limited functional studies have demonstrated a role for the Eph/ephrin system in hematopoiesis and leukemogenesis. In particular, EphA2 was reported on hematopoietic stem cells and stromal cells. There are also reports of EphA2 expression in many different types of malignancies including leukemia, however there is a lack of knowledge in understanding the role of EphA2 in hematopoiesis and leukemogenesis. We explored the role of EphA2 in hematopoiesis by analyzing wild type and EphA2 knockout mice. Mature, differentiated cells, progenitors and hematopoietic stem cells derived from knockout and control mice were analyzed and no significant abnormality was detected. These studies showed that EphA2 does not have an obligatory role in normal hematopoiesis. Comparative studies using EphA2-negative MLL-AF9 leukemias derived from EphA2-knockout animals showed that there was no detectable functional role for EphA2 in the initiation or progression of the leukemic process. However, expression of EphA2 in leukemias initiated by MLL-AF9 suggested that this protein might be a possible therapy target in this type of leukemia. We showed that treatment with EphA2 monoclonal antibody IF7 alone had no effect on tumorigenicity and latency of the MLL-AF9 leukemias, while targeting of EphA2 using EphA2 monoclonal antibody with a radioactive payload significantly impaired the leukemic process. Altogether, these results identify EphA2 as a potential radio-therapeutic target in leukemias with MLL translocation.

Spatial resolution and image qualities of Zr-89 on Siemens Biograph TruePoint PET/CT

PURPOSE

Zirconium-89 (t(1/2)=78.41 hours) is an ideal metallic radioisotope for immuno-positron emission tomography (PET), given that its physical half-life closely matches the biological half-life of monoclonal antibodies. In this study, the authors measured the spatial resolution and image quality of Zr-89 PET and compared the results against those obtained using F-18 PET, which is widely regarded as the gold standard for comparison of imaging characteristics.

MATERIALS AND METHODS

The spatial resolution and image qualities of Zr-89 were measured on the Siemens Biograph Truepoint TrueV PET/CT scanner, partly according to NEMA NU2-2007 standards. For spatial resolution measurement, the Zr-89 point source was located at the center of the axial field of view (FOV) and offset 1/4 axial FOV from the center. For image quality measurements, an NEMA IEC Phantom was used. The NEMA IEC Phantom consists of six hot spheres that were filled with Zr-89 solution. Spatial resolution and image quality (%contrast, %background variability [BV], and source to background ratio [SBR]) were assessed to compare the imaging characteristics of F-18 with those of Siemens Biograph Truepoint TrueV.

RESULTS

The transverse and axial spatial resolutions at 1 cm were 4.5 and 4.7 mm for Zr-89, respectively. The %contrast of Zr-89 was 25.5% for the smallest 10 mm sized sphere and 89.8% for the largest 37 mm sized sphere, and for F-18, it was 32.5% for the smallest 10 mm sized sphere and 103.9% for the largest 37 mm sized sphere using the ordered subset expectation maximization (OSEM) reconstruction method. The %BV of F-18 PET was 6.4% for the smallest 10 mm sized sphere and 3.5% for the largest 37 mm sized sphere using the OSEM reconstruction. The SBR of Zr-89 was 1.8 for the smallest 10 mm sized sphere and 3.7 for the largest 37 mm sized sphere, and for F-18, it was 2.0 for the smallest 10 mm sized sphere and 4.1 for the largest 37 mm sized sphere using the OSEM reconstruction method.

CONCLUSIONS

This study assessed Zr-89 imaging characteristics using a Siemens Biograph Truepoint TrueV PET/CT scanner and compared the results with those obtained for F-18 PET. Although spatial resolution and image quality of Zr-89 PET were lower compared with F-18 PET, due to longer positron range and low positron branching ratio, Zr-89 is advantageous for immuno-PET due to well-matched half-life with monoclonal antibodies.

Radiolabeling strategies for tumor-targeting proteinaceous drugs

Owing to their large size proteinaceous drugs offer higher operative information content compared to the small molecules that correspond to the traditional understanding of druglikeness. As a consequence these drugs allow developing patient-specific therapies that provide the means to go beyond the possibilities of current drug therapy. However, the efficacy of these strategies, in particular "personalized medicine", depends on precise information about individual target expression rates. Molecular imaging combines non-invasive imaging methods with tools of molecular and cellular biology and thus bridges current knowledge to the clinical use. Moreover, nuclear medicine techniques provide therapeutic applications with tracers that behave like the diagnostic tracer. The advantages of radioiodination, still the most versatile radiolabeling strategy, and other labeled compounds comprising covalently attached radioisotopes are compared to the use of chelator-protein conjugates that are complexed with metallic radioisotopes. With the techniques using radioactive isotopes as a reporting unit or even the therapeutic principle, care has to be taken to avoid cleavage of the radionuclide from the protein it is linked to. The tracers used in molecular imaging require labeling techniques that provide site specific conjugation and metabolic stability. Appropriate choice of the radionuclide allows tailoring the properties of the labeled protein to the application required. Until the event of positron emission tomography the spectrum of nuclides used to visualize cellular and biochemical processes was largely restricted to iodine isotopes and 99m-technetium. Today, several nuclides such as 18-fluorine, 68-gallium and 86-yttrium have fundamentally extended the possibilities of tracer design and in turn caused the need for the development of chemical methods for their conjugation.

Synthesis and application of a novel cysteine-based DTPA-NCS for targeted radioimmunotherapy

INTRODUCTION

For the development of safe and effective protein-based radiolabeled complexes such as radioimmunotherapy (RIT), the selection of the radionuclides and the chelating agents used for the radiolabeling of tumor-targeting molecules is a critical factor. We aim to synthesize a novel bifunctional chelating agent containing the isothiocyanate group for easy conjugation with antibodies having the characteristics of high stable chelation with therapeutic radionuclides.

METHODS

We have synthesized the DTPA analogue retaining L-cysteine as a core ligand of the thiol group. The chelating power of cysteine-based DTPA-NCS (cys-DTPA-NCS) was compared with that of commercial ρ-SCN-Bn-DTPA. In an application, the cetuximab was radioimmunoconjugated with (177)Lu using cys-DTPA-NCS. The affinity was tested in a cell line overexpressing EGFR. A therapy study was conducted in nude mice with subcutaneous HT-29 xenografts.

RESULTS

The cys-DTPA-NCS presents an excellent ability to chelate as compared to the ρ-SCN-Bn-DTPA. For mean ratio chemical labeling yields of 95%, the result was 0.97. (177)Lu-cys-DTPA-NCS-cetuximab was prepared under ambient condition with a high radiolabeling yield and the radiochemical purity was sustained for at least 6days. The IC50 value of the (177)Lu-labeled cetuximab was 10nM (95% confidence). The stability and therapeutic efficacy of the candidate radiopharmaceutical were verified.

CONCLUSION

The new DTPA derivative, cys-DTPA-NCS, is a good bifunctional chelating agent that can be used for protein-based radiopharmaceutical using lanthanides such as (177)Lu and (90)Y. The prepared (177)Lu-cys-DTPA-NCS-cetuximab can be used for the diagnosis and treatment of human colorectal tumor.

Iodine-131 rituximab radioimmunotherapy with BEAM conditioning and autologous stem cell transplant salvage therapy for relapsed/refractory aggressive non-Hodgkin lymphoma

A standard salvage therapy of relapsed/refractory aggressive non-Hodgkin lymphoma (NHL) comprises autologous stem cell transplantation (ASCT) after chemotherapy conditioning with carmustine, etoposide, cytarabine, and melphalan (BEAM) regimen. However, the achievement of long-term disease-free survival remains challenging. We have introduced concomitant (131)I-rituximab radioimmunotherapy (RIT) in an attempt to effect the elimination of lymphoma cells. Our phase II physician-sponsored study of 16 consecutive patients with relapsed, refractory, aggressive B-cell NHL reports a median 44 month follow-up after (131)I-rituximab-BEAM conditioning therapy and ASCT. Prospective personalized dosimetry performed in each patient limited the whole body radiation absorbed dose to 0.75 Gy. RIT (131)I-rituximab was administered on an outpatient basis on day -15 before ASCT. The BEAM conditioning regimen was commenced on day -6. Evaluable engraftment data are available for 15 patients who had 16 ASCTs. Engraftment was achieved in all patients, 15 out of 16 ASCTs achieved a complete response, and 1 out of 15 ASCTs achieved a partial response. Twelve out of sixteen patients remained alive and disease free at a median of 44 months (range 4-108 months) post-ASCT. This study suggests that the addition of (131)I-rituximab RIT to BEAM conditioning, before ASCT, for relapsed or primary refractory B-cell NHL improves disease eradication, compared with BEAM conditioning alone, without significant additional toxicity. In particular, there is an impression of improved disease control in the subset of patients with transformed follicular and mantle cell lymphomas.

Surface properties and cell adhesion onto allylamine-plasma and amine-plasma coated glass coverslips

Surface properties of nanoparticles to be used for radioimmunotherapy need to be optimized to allow antibody conjugation while ensuring biocompatibility. We aimed to investigate cell adhesion and proliferation onto different coatings to be used for nanoparticles. C, CH(x) or SiO(x) coatings deposited onto glass coverslips by magnetron deposition as well as nitrogen functionalized materials synthetized using different reactive sputtering conditions and PPAA (plasma polymerized allylamine) coating, were compared. Amine functionalization did increase hydrophilicity in all the materials tested. Biocompatibility was assessed by measuring cell viability, morphology, attachment, spreading, and pro-inflammatory cytokine secretion. The results show that C and CN(x) were the most biocompatible substrates while SiO(x) and SiO(x)N(y) were the most toxic materials. PPAA coatings displayed unexpectedly an intermediate biocompatibility. A correlation could be observed between wettability and cell proliferation except for C coated surface, indicating that more complex processes than hydrophilicity alone are taking place that affect cell functions.

Mantle cell lymphoma: state-of-the-art management and future perspective

Mantle cell lymphoma (MCL) is a unique subtype of B-cell non-Hodgkin lymphomas (NHL) characterized in almost all cases by the chromosomal translocation t(11;14)(q13;q32) and nuclear cyclin D1 overexpression. Most patients present with advanced stage disease, often with extranodal dissemination, and typically pursue an aggressive clinical course. Recent improvement has been achieved by the successful introduction of monoclonal antibodies and dose-intensified approaches including autologous stem cell transplantation strategies. However, with the exception of allogeneic hematopoietic stem cell transplantation, current treatment approaches are not curative and the corresponding survival curve is characterized by a relatively steep and continuous decline, with a median survival of about 4 years and <15% long-term survivors. Despite its rarity, MCL is of particular clinical and scientific interest by providing a paradigm for neoplasms with dysregulated control of cell cycle machinery and impaired apoptotic pathways. Recently gained insights into underlying pathobiology unravel numerous promising molecular targeting strategies, however their introduction into clinical practice and current treatment algorithms remains a challenge. This article will provide relevant information for decision making in clinical practice and give a perspective on upcoming management strategies.

Imaging and pharmacokinetics of (64)Cu-DOTA-HB22.7 administered by intravenous, intraperitoneal, or subcutaneous injection to mice bearing non-Hodgkin's lymphoma xenografts

PURPOSE

The aim of the study is to compare the tumor-specific targeting, pharmacokinetics, and biodistribution of (64)Cu-DOTA-HB22.7 when administered to xenograft-bearing mice intravenously (IV), intraperitoneally (IP), and subcutaneously (SQ).

PROCEDURES

Mice bearing human non-Hodgkin's lymphoma (NHL) xenografts were injected IV, IP, or SQ with (64)Cu-DOTA-HB22.7. Xenograft targeting was evaluated by micro positron emission tomography (microPET) and confirmed by organ biodistribution studies. Blood measurements of (64)Cu were performed to determine the pharmacokinetics and clearance of (64)Cu-DOTA-HB22.7.

RESULTS

(64)Cu-DOTA-HB22.7 demonstrated equivalent tumor targeting within 24-48 h, regardless of the route of administration. Organ biodistribution confirmed tumor-specific targeting. Blood pharmacokinetics demonstrated that (64)Cu-DOTA-HB22.7 accessed the bloodstream after IP and SQ administration to a similar degree as IV administration, albeit at a slower rate.

CONCLUSIONS

These findings establish (64)Cu-DOTA-HB22.7 as a potential radioimmunotherapeutic and/or NHL-specific imaging agent. These findings provide evidence that IP and SQ administration can achieve results equivalent to IV administration and may lead to more efficient, reproducible treatment plans for antibody-based therapeutics.

Plant-produced idiotype vaccines for the treatment of non-Hodgkin's lymphoma: safety and immunogenicity in a phase I clinical study

Plant-made vaccines have been the subject of intense interest because they can be produced economically in large scale without the use of animal-derived components. Plant-made therapeutic vaccines against challenging chronic diseases, such as cancer, have received little research attention, and no previous human clinical trials have been conducted in this vaccine category. We document the feasibility of using a plant viral expression system to produce personalized (patient-specific) recombinant idiotype vaccines against follicular B cell lymphoma and the results of administering these vaccines to lymphoma patients in a phase I safety and immunogenicity clinical trial. The system allowed rapid production and recovery of idiotypic single-chain antibodies (scFv) derived from each patient's tumor and immunization of patients with their own individual therapeutic antigen. Both low and high doses of vaccines, administered alone or co-administered with the adjuvant GM-CSF, were well tolerated with no serious adverse events. A majority (>70%) of the patients developed cellular or humoral immune responses, and 47% of the patients developed antigen-specific responses. Because 15 of 16 vaccines were glycosylated in plants, this study also shows that variation in patterns of antigen glycosylation do not impair the immunogenicity or affect the safety of the vaccines. Collectively, these findings support the conclusion that plant-produced idiotype vaccines are feasible to produce, safe to administer, and a viable option for idiotype-specific immune therapy in follicular lymphoma patients.

Monoclonal antibodies as targeted therapy in hematologic malignancies in older adults

BACKGROUND

Biological agents are proving to be increasingly useful and exciting additions to the antineoplastic armamentarium, but many clinicians are unfamiliar with the properties of these types of agents.

OBJECTIVES

This review focuses on monoclonal antibodies (MAbs) that are used in the treatment of hematologic malignancies. Our goal was to provide the reader with information on trials that led to US Food and Drug Administration (FDA) approval of commonly used MAbs in hematologic malignancies, including their mechanisms of action and pharmacokinetics, with specific emphasis on use in elderly patients; we also present data on toxicities and precautions to be aware of when administering these drugs.

METHODS

Materials for this review were gathered based on a computerized literature search (English-language articles only) using the PubMed database covering the period January 1998 to December 2005. Search terms used included the following: elderly, monoclonal antibodies, and neoplasms.

RESULTS

Alemtuzumab is a recombinant DNA-derived, humanized MAb directed against the CD52 B-cell antigen. It is indicated for the treatment of B-cell chronic lymphocytic leukemia (CLL) in patients who have been treated with alkylating agents and who have failed to respond to fludarabine therapy. Gemtuzumab ozogamicin is an MAb conjugated with a cytotoxic antitumor antibiotic, calicheamicin. It has been approved for use in patients with CD33-positive acute myeloid leukemia (AML) in first relapse who are aged > or =60 years and who are not considered candidates for other cytotoxic chemotherapy. Rituximab, one of the first MAbs approved by the FDA for use in human cancers, is an antibody directed against the CD20 antigen found on the surface of normal and malignant B lymphocytes. It is extensively used in the treatment of B-cell malignancies, such as CLL, and non-Hodgkin's lymphomas (NHLs), such as follicular lymphoma and diffuse large B-cell lymphoma.

CONCLUSIONS

It is noteworthy that while there have been a number of studies using these agents in the younger population, there continues to be a paucity of clinical trials targeting the elderly patient in particular; this continues to be an area of research interest. More clinical studies of these agents--conducted specifically in elderly patients with CLL, NHL, AML, and other hematologic malignancies--are needed.

Pretargeted antibody-guided radioimmunotherapy in a child affected by resistant anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is characterized by preferential paracortical and intrasinusoidal lymph node involvement by large anaplastic tumor cells expressing the CD30 antigen. Up to 80% of pediatric patients with ALCL can be cured with multi-agent chemotherapeutic regimens. Patients resistant to chemotherapy or suffering from early relapse have a poor prognosis and a poor chance of survival. In these cases, the highly aggressive clinical course of ALCL, associated with systemic symptoms and extranodal involvement, has been treated with different approaches in various cooperative trials, including conventional chemotherapy and human stem cell transplantation (HSCT). However, the optimal treatment has not yet been defined, in particular in cases of relapse. More recently, radioimmunotherapy has been studied with encouraging results in cancer patients, including non-Hodgkin's lymphoma. Here we describe the case of a pediatric ALCL, relapsing after HSCT, treated with pretargeted antibody-guided radioimmunotherapy, obtaining a complete remission, with excellent quality of life over the past 10 months.

Malignant lymphomas in the elderly: A single institute experience highlights future directions

In this study, our experience with the diagnostics and treatment of malignant lymphoma patients were analyzed, with a special consideration of the elderly. Between 1980 and 2005, there were 181 cases found (35%) among 517 non-Hodgkin's lymphoma (NHL) patients and 46 cases (8.1%) among 565 Hodgkin's lymphoma (HL) patients, who were at least 65 years old at the time of diagnosis. Comparing elderly patients to young ones, the time from first symptoms to diagnosis was significantly longer (NHL: 7.6 months versus 4.1 months, HL: 11.4 months versus 5.6 months). B-cell and indolent NHL-s were more common (92.8% versus 79.2% and 56.4% versus 35.1%) such as classical lymphocyte predominant (cLP) HL-s (30.4% versus 15.0%); however nodular sclerosis (NS) HL-s occurred less frequently (10.9% versus 32.2%). Stages were more advanced and comorbidity was more common. Primary therapies were more often inappropriate (NHL: 20.4% versus 5.1%, HL: 26.0% versus 6.0%); there were more complications, but less cases with complete remission (NHL: 17.1% versus 61.1%, HL: 63.0% versus 79.2%) and dose reductions were more commonly applied (NHL: 46.7% versus 17.2%, HL: 52.9% versus 11.3%). Remission rates were significantly worsened by dose reductions (NHL: 68.5% versus 34.5%, HL: 61.8% versus 44.4%). Appropriate therapies resulted in significantly better overall survival (OS) rates (log-rank<0.05). It can be concluded that more favourable results can be achieved in the remission and survival rates of elderly malignant lymphoma patients if the appropriate curative or palliative therapies, considering new and less toxic protocols such as supportive care, are chosen.

Radioimmunotherapy of human colon cancer xenografts by using 131I labeled-CAb1 F(ab')2

PURPOSE

Therapeutic efficacy, suitable dose, and administration times of 131I-CAb1 F(ab')2, a new monoclonal antibody therapeutics specifically directed against a cell surface-associated glycoprotein of colon cancer, were investigated in this article.

METHODS AND MATERIALS

In human colon cancer xenografts, 131I-CAb1 F(ab')2 at the dose of 125 muCi, 375 muCi, and 1125 muCi were administrated intraperitoneally on Days 6 and 18 after implantation of HR8348 cells with CAb1 high reactivity. Survival time and tumor growth inhibition rate were used to evaluate the efficacy and safety of 131I-CAb1 F(ab')2 in treatment of colon cancer xenografts.

RESULTS

Treatment of 125, 375, and 1125 muCi 131I-CAb1 F(ab')2 did not significantly decrease the mean survival time of nude mice when compared with nontreated groups (p = 0.276, 0.865, 0.582, respectively). Moreover, the mean survival times of nude mice receiving 375 muCi and 1125 muCi 131I-CAb1 F(ab')2 were significantly longer than that of 5-FU-treated groups (p = 0.018 and 0.042). Tumor growth inhibition rates of the first therapy were 35.67% and 41.37%, with corresponding 131I-labeled antibody dosage of 375 muCi and 1125 muCi. After single attack dosage, second reinforcement therapy may rise efficacy significantly. Tumor growth inhibition rates of 125 muCi, 375 muCi, and 1125 muCi 131I-labeled antibody on Day 20 posttherapy were 42.65%, 56.56%, and 84.41%, respectively. Histopathology examination revealed that tissue necrosis of various degrees was found in 131I-CAb1 F(ab')2-treated groups.

CONCLUSION

131I-CAb1 F(ab')2 is safe and effective for colon cancer. It may be a novel and potentially adjuvant therapeutics for colon cancer.

Single-Photon Emission Computed Tomography/Computed Tomography in Lung Cancer and Malignant Lymphoma

In nuclear oncology, despite the fast-growing diffusion of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), single-photon emission computed tomography (SPECT) studies can still play an useful clinical role in several applications. The main limitation of SPECT imaging with tumor-seeking agents is the lack of the structural delineation of the pathologic processes they detect; this drawback sometimes renders SPECT interpretation difficult and can diminish its diagnostic accuracy. Fusion with morphological studies can overcome this limitation by giving an anatomical map to scintigraphic data. In the past, software-based fusion of independently performed SPECT and CT images proved to be time-consuming and impractical for routine use. The recent development of dual-modality integrated imaging systems that provide functional (SPECT) and anatomical (CT) images in the same scanning session, with the acquired images coregistered by means of the hardware, has opened a new era in this field. The first reports indicate that SPECT/CT is very useful in cancer imaging because it is able to provide further information of clinical value in several cases. In SPECT, studies of lung cancer and malignant lymphomas using different radiopharmaceutical, hybrid images are of value in providing the correct localization of tumor sites, with a precise detection of the involved organs, and the definition of their functional status, and in allowing the exclusion of disease in sites of physiologic tracer uptake. Therefore, in lung cancer and lymphomas, hybrid SPECT/CT can play a role in the diagnosis of the primary tumor, in the staging of the disease, in the follow-up, in the monitoring of therapy, in the detection of recurrence, and in dosimetric estimations for target radionuclide therapy.

Recommendations for the use of Yttrium-90 ibritumomab tiuxetan in malignant lymphoma

Radioimmunotherapy (RIT) with Yttrium-90 (90Y) ibritumomab tiuxetan (Zevalin) combines the tumor targeting attributes of a monoclonal antibody against the CD20 antigen and the pure beta-radiation of 90Y. High efficacy and a favorable safety profile have been demonstrated in Phase II and III clinical trials enrolling patients with CD20+ B-cell non-Hodgkin lymphoma (B-NHL). On the basis of these results, 90Y-ibritumomab tiuxetan was approved in the United States for the treatment of patients with follicular lymphoma (FL) or transformed B-NHL. In the European Union its use was restricted to FL, refractory to or relapsed after rituximab. There are a number of important clinical trials currently evaluating 90Y-ibritumomab tiuxetan in other subtypes of lymphoma such as diffuse large-cell and mantle-cell lymphoma, as consolidation therapy or as part of myeloablative regimens. In light of the constantly increasing clinical experience with RIT, clinicians face the challenge of how to best integrate this promising new treatment option into existing established treatment algorithms. By incorporating the most recent data in this rapidly developing field, this review article focuses on current recommendations for the use of 90Y-ibritumomab tiuxetan in patients with malignant lymphoma, outlines future perspectives, and provides practical recommendations for patient management.