Selective Personalized RadioImmunotherapy for Locally Advanced Non-Small-Cell Lung Cancer Trial (SPRINT)

PURPOSE

Standard therapy for locally advanced non-small-cell lung cancer (LA-NSCLC) is concurrent chemoradiotherapy followed by adjuvant durvalumab. For biomarker-selected patients with LA-NSCLC, we hypothesized that sequential pembrolizumab and risk-adapted radiotherapy, without chemotherapy, would be well-tolerated and effective.

METHODS

Patients with stage III NSCLC or unresectable stage II NSCLC and an Eastern Cooperative Oncology Group performance status of 0-1 were eligible for this trial. Patients with a PD-L1 tumor proportion score (TPS) of ≥50% received three cycles of induction pembrolizumab (200 mg, once every 21 days), followed by a 20-fraction course of risk-adapted thoracic radiotherapy (55 Gy delivered to tumors or lymph nodes with metabolic volume exceeding 20 cc, 48 Gy delivered to smaller lesions), followed by consolidation pembrolizumab to complete a 1-year treatment course. The primary study end point was 1-year progression-free survival (PFS). Secondary end points included response rates after induction pembrolizumab, overall survival (OS), and adverse events.

RESULTS

Twenty-five patients with a PD-L1 TPS of ≥50% were enrolled. The median age was 71, most patients (88%) had stage IIIA or IIIB disease, and the median PD-L1 TPS was 75%. Two patients developed disease progression during induction pembrolizumab, and two patients discontinued pembrolizumab after one infusion because of immune-related adverse events. Using RECIST criteria, 12 patients (48%) exhibited a partial or complete response after induction pembrolizumab. Twenty-four patients (96%) received definitive thoracic radiotherapy. The 1-year PFS rate is 76%, satisfying our efficacy objective. One- and 2-year OS rates are 92% and 76%, respectively. The most common grade 3 adverse events were colitis (n = 2, 8%) and esophagitis (n = 2, 8%), and no higher-grade treatment-related adverse events have occurred.

CONCLUSION

Pembrolizumab and risk-adapted radiotherapy, without chemotherapy, are a promising treatment approach for patients with LA-NSCLC with a PD-L1 TPS of ≥50%.

Prognostic relevance of clonal hematopoiesis in myeloid neoplastic transformation in patients with follicular lymphoma treated with radioimmunotherapy

While novel radioisotope therapies continue to advance cancer care, reports of therapy-related myeloid neoplasms (t-MN) have generated concern. The prevalence and role of clonal hematopoiesis (CH) in this process remain to be defined. We hypothesized that: (i) CH is prevalent in relapsed follicular lymphoma and is associated with t-MN transformation, and (ii) radiation in the form of radioimmunotherapy (RIT) plays a role in clonal progression. In this retrospective cohort study, we evaluated the prevalence and prognostic impact of CH on clinical outcomes in 58 heavily pre-treated follicular lymphoma patients who received RIT. Patients had been given a median of four lines of therapy before RIT. The prevalence of CH prior to RIT was 46%, while it was 67% (P=0.15) during the course of RIT and subsequent therapies in the paired samples. Fourteen (24%) patients developed t-MN. Patients with t-MN had a higher variant allele fraction (38% vs. 15%; P=0.02) and clonal complexity (P=0.03) than those without. The spectrum of CH differed from that in age-related CH, with a high prevalence of DNA damage repair and response pathway mutations, absence of spliceosome mutations, and a paucity of signaling mutations. While there were no clear clinical associations between RIT and t-MN, or overall survival, patients with t-MN had a higher mutant clonal burden, along with extensive chromosomal abnormalities (median survival, afer t-MN diagnosis, 0.9 months). The baseline prevalence of CH was high, with an increase in prevalence on exposure to RIT and subsequent therapies. The high rates of t-MN with marked clonal complexities and extensive chromosomal damage underscore the importance of better identifying and studying genotoxic stressors accentuated by therapeutic modalities.

Radioimmunotherapy with 131 I-rituximab for patients with relapsed or refractory follicular or mantle cell lymphoma

AIM

This study aimed to evaluate the safety and efficacy of 131 I-rituximab in patients with relapsed or refractory follicular or mantle cell lymphoma.

METHODS

Twenty-four patients with relapsed or refractory follicular or mantle cell lymphoma were administered unlabeled rituximab (70 mg) immediately before receiving a therapeutic dose of 131 I-rituximab. Contrast-enhanced 18F-fluorodeoxyglucose positron emission tomography/computed tomography was used a month later to assess tumor response.

RESULTS

This study enrolled 24 patients between June 2012 and 2022. Depending on how they responded to radioimmunotherapy (RIT), 131 I-rituximab was administered one to five times. Of the 24 patients, 9 achieved complete response after RIT and 8 achieved partial response. The median progression-free and overall survival was 5.9 and 37.9 months, respectively. During the follow-up period of 64.2 months, three patients were diagnosed with a secondary malignancy. Among treatment-related adverse events, hematologic toxicities were common, and grade 3-4 thrombocytopenia and neutropenia were reported in 66.6% of cases.

CONCLUSION

131 I-rituximab has an effective and favorable safety profile in patients with relapsed or refractory follicular lymphoma and mantle cell lymphoma. This suggests that RIT may also be considered a treatment option for patients with relapsed or refractory follicular lymphoma and mantle cell lymphoma.

Real World Long-term Follow-up Experience with Yttrium-90 ibritumomab tiuxetan in Previously Untreated Patients with Low-Grade Follicular Lymphoma and Marginal Zone Lymphoma

INTRODUCTION

Yttrium-90 ibritumomab tiuxetan [(90)Y-IT] is a CD20-targeted radio-immuno conjugate. Clinical trials of (90)Y-IT as a first-line stand-alone treatment in follicular lymphoma (FL) and/or marginal zone lymphoma (MZL) showed high efficacy. However, long-term survival outcomes and toxicities are not well-defined.

METHODS

We report a retrospective single-institution, multi-center study of (90)Y-IT in previously untreated low grade (LG)-FL and MZL at Mayo Clinic Cancer Center between January 2000 and October 2019. We selected patients with LG-FL and MZL who received standard-dose (90)Y-IT as a single agent in the first line setting.

RESULTS

The cohort (n = 51) consists of previously untreated LG-FL (n = 41) or MZL (n = 10). Median follow-up was 5.3 years (95% CI; 4.2, 6.2). Overall response rate (ORR) was 100% with complete response rate (CR) of 94%. Continuous CR was observed in 59% patients who had more than 2 years of follow-up. Long-term CR (>7 years) was seen in 25% of patients. Median progression free survival (mPFS) for the whole cohort was not reached (NR) (95% CI; 4.9, NR). Bulky disease was associated with shorter median PFS of 3.5 years (CI 95%; 0.8, 4.9) compared to non-bulky disease NR (CI 95%; 5.8, NR), P = .02. The incidence of grade 3 or higher thrombocytopenia, neutropenia and anemia were 47%, 37%, and 4% respectively. No therapy-related myelodysplasia or acute myeloid leukemia were observed.

CONCLUSION

Long real-life follow-up showed that single-agent (90)Y-IT is highly efficacious with durable long-term survival in previously untreated LG-FL and MZL without significant risk for secondary malignancies.

Induction chemoimmunotherapy followed by CD8+ immune cell-based patient selection for chemotherapy-free radioimmunotherapy in locally advanced head and neck cancer

PURPOSE

The first aim of the trial is to study feasibility of combined programmed death protein ligand 1/cytotoxic T-lymphocyte-associated protein 4 inhibition concomitant to radiotherapy. In addition, efficacy of the entire treatment scheme consisting of induction chemoimmunotherapy followed by chemotherapy-free radioimmunotherapy (RIT) after intratumoral CD8 +immune cell-based patient selection will be analyzed.

METHODS

Patients with stage III-IVB head and neck squamous cell carcinoma were eligible for this multicenter phase II trial. Treatment consisted of a single cycle of cisplatin 30 mg/m² days 1-3, docetaxel 75 mg/m² day 1, durvalumab 1500 mg fix dose day 5 and tremelimumab 75 mg fix dose day 5. Patients with increased intratumoral CD8 +immune cell density or pathological complete response (pCR) in the rebiopsy entered RIT up to a total dose of 70 Gy. Patients received further three cycles of durvalumab/tremelimumab followed by eight cycles of durvalumab mono (every 4 weeks). The intended treatment for patients not meeting these criteria was standard radiochemotherapy outside the trial. Primary endpoint was a feasibility rate of patients entering RIT to receive treatment until at least cycle 6 of immunotherapy of ≥80%.

RESULTS

Between September 2018 and May 2020, 80 patients were enrolled (one excluded). Out of these, 23 patients had human papilloma virus (HPV)-positive oropharyngeal cancer. Median follow-up was 17.2 months. After induction chemoimmunotherapy 41 patients had pCR and 31 had increased intratumoral CD8 +immune cells. Of 60 patients entering RIT (primary endpoint cohort), 10 experienced imiting toxic (mainly hepatitis) and four discontinued for other reasons, resulting in a feasibility rate of 82%. The RIT cohort (n=60) had a progression-free survival (PFS) rate at one and 2 years of 78% and 72%, respectively, and an overall survival rate at one and 2 years of 90% and 84%, respectively. Patients with HPV-positive oropharyngeal cancers had greater benefit from RIT with a 2-year PFS rate of 94% compared with 64% for HPV-negative oropharyngeal cancers and other locations. In the entire study cohort (n=79) the 2-year PFS rate was 68% (91% for HPV-positive oropharynx vs 59% for others). Toxicity grade 3-4 mainly consisted of dysphagia (53%), leukopenia (52%) and infections (32%).

CONCLUSIONS

The trial met the primary endpoint feasibility of RIT. Induction chemo-immunotherapy followed by chemotherapy-free RIT after intratumoral CD8 +immune cell-based patient selection has promising PFS.

TRIAL REGISTRATION NUMBER

The trial was registered with ClinicalTrials.gov (identifier: NCT03426657). The trial was conducted as investigator-sponsored trial (IST).

Pretherapeutic estimated glomerular filtration rate predicts development of chronic kidney disease in patients receiving PSMA-targeted radioligand therapy

BACKGROUND

Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) may be associated with renal toxicity. We aimed to identify predictive parameters for the development of chronic kidney disease (CKD) in patients with metastatic castration resistant prostate cancer (mCRPC) undergoing RLT.

METHODS

In 46 mCRPC patients scheduled for Lu-177-PSMA-RLT, pretherapeutic estimated glomerular filtration rate (eGFR [ml/min/1.73 m² ]), Tc-99m-mercaptoacetyltriglycine (Tc-99m-MAG3) clearance and baseline Ga-68-PSMA-ligand positron emission tomography (PET)-derived renal cortical uptake and PSMA-tumor volume (TV) were determined. We tested the predictive capability of these parameters and clinical risk factors for the occurrence of CKD (defined as CTCAE vers. 5.0 grade 2 or higher) during follow-up.

RESULTS

After 4 ± 3 cycles of RLT average eGFR declined from 76 ± 17 to 72 ± 20 ml/min/1.73 m² (p = 0.003). Increased estimated renal radiation dose (eRRD) was significantly associated with renal functional decline (p = 0.008). During follow-up, 16/46 (30.4%) developed CKD grade 2 (no grade 3 or higher). In receiver operating characteristic (ROC) analysis, pretherapeutic eGFR was highly accurate in identifying the occurrence of CKD vs no CKD with an area under the curve (AUC) of 0.945 (p < 0.001; best threshold, 77 ml/min/1.73 m² ), followed by Tc-99m-MAG3-derived tubular extraction rate (TER; AUC, 0.831, p < 0.001; best threshold, 200 ml/min/1.73 m² ). Renal PET signal (p = 0.751) and PSMA-TV (p = 0.942), however, were not predictive. Kaplan-Meier analyses revealed adverse renal outcome for patients with lower eGFR (p = 0.001) and lower scintigraphy-derived TER (p = 0.009), with pretherapeutic eGFR emerging as the sole predictive parameter in multivariate analysis (p = 0.007).

CONCLUSION

Serious adverse renal events are not a frequent phenomenon after PSMA-targeted RLT. However, in patients developing moderate CKD after RLT, pretherapeutic eGFR is an independent predictor for renal impairment during follow-up.

Adverse events of radioimmunotherapy for non-Hodgkin lymphoma: A systematic review and meta-analysis

Non-Hodgkin's lymphoma continues to be a highly prevalent entity in the general population. Currently, there are multiple treatment schemes based on chemotherapeutic agents with a great success rate. However, there is a non-negligible percentage of patients who may relapse or be refractory. In this sense, new therapeutic options have emerged in the search for adequate responses, such as monoclonal antibodies that target the CD20 molecule. Another valid option is radioimmunotherapy (RIT), which combines using monoclonal antibodies for the specific targeting of malignant cells and radiation to destroy these cells. Despite the promising results that favor RIT in several clinical studies in different target populations and types of NHL, one situation to consider is the association of this therapy and second neoplasms (acute myeloid leukemia (AML) or myelodysplastic syndrome (MSD)). In this sense, we have proposed this meta-analysis to analyze the published information and determine the incidence of this association and determine this therapy's safety.

Radiation Safety for Yttrium-90-polymer Composites (RadioGel™) in Therapy of Solid Tumors

ABSTRACT

Yttrium-90 (90Y)-polymer composite (RadioGel™) is a new cancer therapeutic agent for treating solid tumors by direct interstitial injection. The 90Y-composite comprises insoluble, microscopic yttrium-phosphate particles carried by a sterile, injectable water-polymer (hydrogel) solution that can be placed directly by needle injection into solid tumors. The yttrium-90-RadioGel™ agent was designed to provide a safe, effective, localized, high-dose beta radiation for treating solid tumors. The properties of 90Y-RadioGel™ also make it a relatively safe agent for health care personnel who prepare, handle, and administer the material. The purpose of this work was to demonstrate and characterize radiation safety of the injectable 90Y-RadioGel™ therapeutic agent. Safety in the patient is defined by its ability to target precisely and remain confined within tumor tissue so that radiation doses are imparted to the tumor and not to normal organs and tissues. Radiation safety for health care personnel is defined by the low radiation doses received by persons who prepare and administer the agent. These safety features were demonstrated during experiments, first involving laboratory rabbits and second in cat and dog animal patients that were treated clinically for sarcoma tumors. This paper focuses mainly on the rabbit tissue biodistribution study; follow-on clinical application in cat and dog subjects confirmed the rabbit results. Implanted VX2 liver tumors in the hind limbs of 26 New Zealand White rabbits were treated using tracer amounts of either (a) 90Y-RadioGel™ or (b) 90Y-microparticles in phosphate-buffered saline (PBS) without the gel carrier. Tumor and margin injections were interstitial. Rabbits were euthanized at 48 h or 10 d following injection. Blood and tissues (tumor or tumor margins, liver, lymph nodes, rib bone, kidney, spleen) were collected for liquid scintillation counting using wet-ash procedures. Biodistribution was also analyzed at 10 d post-injection using micro-computed tomography. Thirteen cat and dog subjects were also treated clinically for sarcomas. Liquid scintillation counting at 48 h post-injection of tumors or margins with 90Y-RadioGel™ showed that significant radioactivity was measurable only at the site of administration and that radioactivity above detector background was not found in blood or peripheral organs and tissues. At 10 d post-injection, microCT showed that yttrium phosphate microparticles were confined to the injection site. Yttrium-90 remained where placed and did not migrate away in significant amounts from the injection site. Radiation doses were confined mainly to tumors and margin tissues. During preparation and administration, radiation doses to hands and body of study personnel were negligible. This work showed that 90Y-RadioGel™ can be safely prepared and administered and that radiation doses to cancer patients are confined to tumor and margin tissues rather than to critical normal organs and tissues.

An autoimmune-based, paraneoplastic neurologic syndrome following checkpoint inhibition and concurrent radiotherapy for merkel cell carcinoma: case report

PURPOSE

Merkel cell carcinoma is highly sensitive to both radiation and immunotherapy. Moreover, concurrent radioimmunotherapy may capitalize on anti-tumor immune activity and improve Merkel cell treatment response, although an enhanced immune system may cross-react with native tissues and lead to significant sequelae.

METHODS

Here we present a case study of a patient with metastatic Merkel cell carcinoma treated with radiotherapy concurrent with pembrolizumab.

RESULTS

After radioimmunotherapy, the patient developed sensory neuropathy, visual hallucinations, and mixed motor neuron findings. Neurologic dysfunction progressed to profound gastrointestinal dysmotility necessitating parenteral nutrition and intubation with eventual expiration.

CONCLUSION

This case represents a unique autoimmune paraneoplastic neurologic syndrome, likely specific to neuroendocrine tumors and motivated by concurrent radioimmunotherapy. Recognition of the potential role of radioimmunotherapy may provide an advantage in anticipating these severe sequelae.

Advances in targeted alpha therapy for prostate cancer

Amongst therapeutic radiopharmaceuticals, targeted alpha therapy (TαT) can deliver potent and local radiation selectively to cancer cells as well as the tumor microenvironment and thereby control cancer while minimizing toxicity. In this review, we discuss the history, progress, and future potential of TαT in the treatment of prostate cancer, including dosimetry-individualized treatment planning, combinations with small-molecule therapies, and conjugation to molecules directed against antigens expressed by prostate cancer cells, such as prostate-specific membrane antigen (PSMA) or components of the tumor microenvironment. A clinical proof of concept that TαT is efficacious in treating bone-metastatic castration-resistant prostate cancer has been demonstrated by radium-223 via improved overall survival and long-term safety/tolerability in the phase III ALSYMPCA trial. Dosimetry calculation and pharmacokinetic measurements of TαT provide the potential for optimization and individualized treatment planning for a precision medicine-based cancer management paradigm. The ability to combine TαTs with other agents, including chemotherapy, androgen receptor-targeting agents, DNA repair inhibitors, and immuno-oncology agents, is under investigation. Currently, TαTs that specifically target prostate cancer cells expressing PSMA represents a promising therapeutic approach. Both PSMA-targeted actinium-225 and thorium-227 conjugates are under investigation. The described clinical benefit, safety and tolerability of radium-223 and the recent progress in TαT trial development suggest that TαT occupies an important new role in prostate cancer treatment. Ongoing studies with newer dosimetry methods, PSMA targeting, and novel approaches to combination therapies should expand the utility of TαT in prostate cancer treatment.

Radioimmunotherapy of Gastrointestinal Cancer and Glioblastomas

Two groups of patients with gastro-intestinal (GI) tumours (41) and recurrent glioblastoma (GBM), (17) underwent radioimmunotherapy after the failure of traditional treatments. A number of different MAbs were employed (anti-CEA and anti-Tenascin) which were labelled with I-131. The radiopharmaceuticals were administered by the intraperitoneal and intratumoral routes. As a rule the cycles were repeated to enhance the effectiveness of RIT. No significant early or late adverse effects were recorded. HAMA development was observed in all GI cases but only in a few GBM patients. The cumulative dose delivered to the target tumors was considerable (mean 8,900 cGy) in the GI group, and was much higher in the GBM patients (mean 51,700 cGy) owing to the particular modality of injection. Survival improved in both series of patients. The objective responses to RIT were promising: in the GI group 10 complete remissions (CR) and 6 partial remissions (PR) were observed, while in the GBM group 3 long-lasting CRs and 3 prolonged PRs were documented.

Radioimmunotherapy for Breast Cancer: Treatment of a Patient with I-131 L6 Chimeric Monoclonal Antibody

We report the first treatment of metastatic breast cancer by systemic radioimmunotherapy. The serial therapy doses were chosen based on quantitative imaging data in a treatment planning approach. A terminally ill patient with aggressive, locally advanced breast cancer who had failed radiation treatment and chemotherapy was injected intravenously with radiolabeled I-131 chimeric L6, a human-mouse chimeric IgG1 monoclonal antibody to adenocarcinoma. Initially, an imaging 10 mCi dose of 1-131 chimeric L6 (dose 1) deposited 8.8% of the injected dose in her chest wall tumor at 48 hours. Ten days later the patient was given a 150 mCi I-131 chimeric L6 dose (dose 2) followed three weeks later by a 100 mCi dose (dose 3). Tumor uptake and retention were comparable for doses 1 and 2, and decreased for dose 3. Following dose 3 the patient developed a manageable thrombocytopenia and transient Grade IV granulocytopenia. The tumor was observed to decrease in size with peak tumor regression occurring two weeks after dose 3. This partial response (PR) was achieved by radioimmunotherapy at a time when conventional therapy had been unable to impact the growth of the patient's massive and aggressive tumor.

Analysis of antiglobulin (HAMA) response in a group of patients with B-lymphocytic malignancies treated with 131I-Lym-1

Host development of human anti-mouse antibodies (HAMA) in response to administered antibodies has been reported as a problem for antibody imaging and therapy. However, radioimmunotherapy has been shown to be effective in patients with B-cell malignancies because their immunodeficient state precludes or delays development of a HAMA response to mouse antibodies. Baseline HAMA activity was assayed in 60 patients with B-lymphocytic non-Hodgkin's lymphoma or chronic lymphocytic leukemia and sequentially in 43 patients who were subsequently treated with radiolabeled Lym-1 antibody. Pre-existing “HAMA” activity was found in 3 (5%) of the 60 patients screened for treatment consideration. The incidence of development of HAMA in the 43 patients treated with multiple doses of radiolabeled Lym-1 antibody was 12 (28%). There was no evidence for an anaphylactoid or related response in the HAMA positive patients. HAMA activity interrupted therapy in 14% of the patients (6 of 43) but did not preclude therapeutic responses to radiolabeled Lym-1 therapy. Median survival for the HAMA positive patients was longer (18 months) than for those who did not develop HAMA activity (9 months).

Radioimmunotherapy of cancer with high linear energy transfer (LET) radiation delivered by radionuclides emitting α-particles or Auger electrons

Radioimmunotherapy (RIT) aims to selectively deliver radionuclides emitting α-particles, β-particles or Auger electrons to tumors by conjugation to monoclonal antibodies (mAbs) that recognize tumor-associated antigens/receptors. The approach has been most successful for treatment of non-Hodgkin's B-cell lymphoma but challenges have been encountered in extending these promising results to the treatment of solid malignancies. These challenges include the low potency of β-particle emitters such as ¹³¹I, ¹⁷⁷Lu or ⁹⁰Y which have been commonly conjugated to the mAbs, due to their low linear energy transfer (LET=0.1-1.0keV/μm). Furthermore, since the β-particles have a 2-10mm range, there has been dose-limiting non-specific toxicity to hematopoietic stem cells in the bone marrow (BM) due to the cross-fire effect. Conjugation of mAbs to α-particle-emitters (e.g. ²²⁵Ac, ²¹³Bi, ²¹²Pb or ²¹¹At) or Auger electron-emitters (e.g. ¹¹¹In, ⁶⁷Ga, ¹²³I or ¹²⁵I) would increase the potency of RIT due to their high LET (50-230keV/μm and 4 to 26keV/μm, respectively). In addition, α-particles have a range in tissues of 28-100μm and Auger electrons are nanometer in range which greatly reduces or eliminates the cross-fire effect compared to β-particles, potentially reducing their non-specific toxicity to the BM. In this review, we describe the results of preclinical and clinical studies of RIT of cancer using radioimmunoconjugates emitting α-particles or Auger electrons, and discuss the potential of these high LET forms of radiation to improve the outcome of cancer patients.

Optimizing Radiotherapy with Immunotherapeutic Approaches

Several factors must be considered to successfully integrate immunotherapy with radiation into clinical practice. One such factor is that concepts arising from preclinical work must be tested in combination with radiation in preclinical models to better understand how combination therapy will work in patients; examples include checkpoint inhibitors, tumor growth factor-beta (TGF-β) inhibitors, and natural killer (NK) cell therapy. Also, many radiation fields and fractionation schedules typically used in radiation therapy had been standardized before the introduction of advanced techniques for radiation planning and delivery that account for changes in tumor size, location, and motion during treatment, as well as uncertainties introduced by variations in patient setup between treatment fractions. As a result, radiation therapy may involve the use of large treatment volumes, often encompassing nodal regions that may not be irradiated with more conformal techniques. Traditional forms of radiation in particular pose challenges for combination trials with immunotherapy. This chapter explores these issues in more detail and provides insights as to how radiation therapy can be optimized to combine with immunotherapy.

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future.

Effectiveness and Safety of Radioactive Iodine Therapy in Childhood Graves’ Disease in Khon Kaen, Thailand

BACKGROUND

Graves’ disease (GD) is the most common cause of hyperthyroidism in children and adolescents. Treatments consist of medication, radioactive iodine (RAI) therapy and surgery. Currently, radioactive iodine therapy is the first line treatment in many medical centers.

OBJECTIVE

To evaluate the effectiveness and safety of RAI therapy in childhood GD.

MATERIAL AND METHOD

A retrospective study was performed in 46 GD patients, aged at onset <15 years, who had undergone RAI therapy at the age >10 years. Goiter grading, evidence of hypothyroidism, severity of ophthalmopathy, RAI dosage and side effects of RAI therapy were evaluated.

RESULTS

The cure rate was 95.6%. All participating patients had goiter reduction (p = 0.005). Hypothyroidism was induced in 33 (71.7%) and 11 (23.9%) patients after the first and second RAI therapy. The total RAI dosage was significantly higher in the patients with failure response (p = 0.001). The average time to induce hypothyroidism after the first RAI therapy was 127.5 (IQR: 94.5-223.0) days. All of the patients had improvement of ophthalmopathy and none had thyroid carcinoma during the follow-up period of 42.5 (IQR: 17-52) months.

CONCLUSION

Radioactive iodine therapy is effective and safe in the treatment of children and adolescents with Graves’ disease.

Long-term complication in follicular lymphoma: assessing the risk of secondary neoplasm in 242 patients treated or not with 90-yttrium-ibritumomab-tiuxetan

BACKGROUND

Non-Hodgkin lymphoma patients have a 25% increased risk of secondary primary neoplasms (SPNs). Regarding the controversy about the increased risk of SPN in patients exposed to radioimmunotherapy (RIT), we have analyzed this issue in a cohort of follicular lymphoma (FL) patients treated with/without RIT.

PATIENTS AND METHODS

A retrospective study including all consecutive FL patients diagnosed since 2001 was performed. Demographic, clinical data including the incidence of any kind of neoplasm (excluding basocellular skin carcinoma) were recorded.

RESULTS

A total of 242 patients were registered, male/female: 103/139, mean age: 59.9 yr (15-86), stage IV (57.8%), and Follicular Lymphoma Prognostic Index (FLIPI) low-risk (62.15%) predominance. Ninety-six patients (39.7%) were treated with 90Y-IT. The median follow-up for patients treated or not with 90Y-IT was 61 (8-273) and 38 (1-171) months. With respect to SPN incidence, 38 (15.6%) patients have at least two cancers, in 17 (44.7%), FL was the SPN; for the rest (226), the global incidence of SPNs was 9.3% (21), but there were no differences related to the exposition or not to 90Y-IT (P = 0.26). In seven patients, more than two (2-6) different therapies were registered; four were exposed to fludarabine-based therapy, three to radiotherapy and two to autologous stem-cell transplantation, and in the RIT cohort, two patients developed myelodysplastic syndrome.

CONCLUSION

This is one of the largest single institution reports assessing the risk of SPN in FL patients treated (96) or not (146) with 90Y-IT. It seems that 90Y-IT does not increase significantly the risk of SPN but avoiding its use after fludarabine and other intense cytotoxic schemes is recommended.

Short duration immunochemotherapy followed by radioimmunotherapy consolidation is effective and well tolerated in relapsed follicular lymphoma: 5-year results from a UK National Cancer Research Institute Lymphoma Group study

We report a phase II study to evaluate the efficacy and toxicity of abbreviated immunochemotherapy followed by (90) Y Ibritumomab tiuxetan ((90) Y-IT) in patients with recurrent follicular lymphoma. Of the 52 patients enrolled, 50 were treated with three cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) or R-CVP (rituximab, cyclophosphamide, vincristine, prednisolone), followed by (90) Y-IT regimen (15 MBq/kg, maximum 1200 MBq) preceded by two infusions of 250 mg/m(2) rituximab. The overall response rate was 98% with complete response (CR) 30% and partial response (PR) 68%. 18 patients with a PR following chemotherapy improved to a CR following (90) Y-IT: a conversion rate of 40%. Seven patients with PR following (90) Y-IT subsequently improved to a CR 12-18 months later, leading to an overall CR rate of 44%. With a median follow-up of 5 years, median progression-free survival was 23·1 months and overall survival was 77·5% at 5 years. High trough serum rituximab levels (median 112 μg/ml; range 52-241) were attained after four doses of rituximab, prior to (90) Y-IT; this was not found to influence response rates. The treatment was well tolerated with few (13·5%) grade 3 or 4 infective episodes and manageable haematological toxicity. Abbreviated immunochemotherapy followed by (90) Y-IT is an effective and well-tolerated treatment in recurrent follicular lymphoma patients previously exposed to rituximab.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00637832.

A randomized study comparing the effectiveness of microwave ablation radioimmunotherapy and postoperative adjuvant chemoradiation in the treatment of non-small cell lung cancer

PURPOSE

To evaluate the differences in the outcomes of patients with stage II and IIIa non-small cell lung cancer (NSCLC) treated with either 131I-labeled mouse/human chimeric monoclonal antibody against intracellular DNA exposed in necrotic and degenerating regions of tumors (131I-chTNT-mediated radioimmunotherapy) combined with percutaneous microwave coagulation therapy (PMCT) guided by computed tomography (CT) or with postoperative adjuvant chemoradiation.

METHODS

Ninety-six patients with stage II and IIIa NSCLC were randomized into two groups. Group A included 49 patients who were treated with chemotherapy with docetaxel and cisplatin and three-dimensional conformal radiotherapy 3-4 weeks after surgery. Group B included 47 patients treated with 131I-chTNT and PMCT sequentially, with follow-up chemotherapy.

RESULTS

The survival rates of patients in group A for the first and second years were 79.59% and 48.98%, respectively. The median survival was 23.0 months. Survival rates at 1 and 2 years for group B were 82.98% and 53.19%, respectively and the median survival was 29.1 months. The survival rate of group B patients for the first and second years was better compared with group A, and the difference in median survival between the groups was statistically significant (p<0.05). However, median survival and the incidence of adverse events were not significantly different between the two groups.

CONCLUSIONS

131I-chTNT radioimmunotherapy with PMCT has a complementary effect in NSCLC, which can effectively improve therapeutic ratio and survival of patients effectively and has the same effect as that of post-operative adjuvant chemoradiation.

Comparative efficacy of 177Lu and 90Y for anti-CD20 pretargeted radioimmunotherapy in murine lymphoma xenograft models

PURPOSE

Pretargeted radioimmunotherapy (PRIT) is a multi-step method of selectively delivering high doses of radiotherapy to tumor cells while minimizing exposure to surrounding tissues. Yttrium-90 (90Y) and lutetium-177 (177Lu) are two of the most promising beta-particle emitting radionuclides used for radioimmunotherapy, which despite having similar chemistries differ distinctly in terms of radiophysical features. These differences may have important consequences for the absorbed dose to tumors and normal organs. Whereas 90Y has been successfully applied in a number of preclinical and clinical radioimmunotherapy settings, there have been few published pretargeting studies with 177Lu. We therefore compared the therapeutic potential of targeting either 90Y or 177Lu to human B-cell lymphoma xenografts in mice.

METHODS

Parallel experiments evaluating the biodistribution, imaging, dosimetry, therapeutic efficacy, and toxicity were performed in female athymic nude mice bearing either Ramos (Burkitt lymphoma) or Granta (mantle cell lymphoma) xenografts, utilizing an anti-CD20 antibody-streptavidin conjugate (1F5-SA) and an 90Y- or 177Lu-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-biotin second step reagent.

RESULTS

The two radionuclides displayed comparable biodistributions in tumors and normal organs; however, the absorbed radiation dose delivered to tumor was more than twice as high for 90Y (1.3 Gy/MBq) as for 177Lu (0.6 Gy/MBq). More importantly, therapy with 90Y-DOTA-biotin was dramatically more effective than with 177Lu-DOTA-biotin, with 100% of Ramos xenograft-bearing mice cured with 37 MBq 90Y, whereas 0% were cured using identical amounts of 177Lu-DOTA-biotin. Similar results were observed in mice bearing Granta xenografts, with 80% of the mice cured with 90Y-PRIT and 0% cured with 177Lu-PRIT. Toxicities were comparable with both isotopes.

CONCLUSION

90Y was therapeutically superior to 177Lu for streptavidin-biotin PRIT approaches in these human lymphoma xenograft models.

131I-labeled metuximab combined with chemoembolization for unresectable hepatocellular carcinoma

AIM: To investigate the safety and effectiveness of combined ¹³¹I-metuximab and transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

METHODS: One hundred and eighty-five patients (159 men and 26 women) with advanced HCC were enrolled in this study from February 2009 to July 2011. There were 95 patients in the combined metuximab and TACE group, and 90 patients in the TACE only group. The patients were followed for 12 mo. Clinical symptoms, blood cell counts, Karnofsky Performance Score (KPS) evaluation and therapeutic effects according to the Response Evaluation Criteria in Solid Tumors were recorded and evaluated.

RESULTS: The 1-mo effective rates (complete response + partial response + stable disease) of the test group and control group were 71.23% and 38.89%, respectively (P < 0.001). The 6-, 9- and 12-mo survival rates were 86.42%, 74.07% and 60.49% for the test group and 60.0%, 42.22% and 34.44% for the control group (P < 0.001). The incidence of adverse events (gastrointestinal symptoms, fever and pain) and blood cell toxicity were significantly higher for the test group than for the control group (P < 0.001). No severe ¹³¹I-metuximab-related complications were identified. With respect to efficacy, patients in the test group had greater improvement in tumor-related pain (P = 0.014) and increase in KPS (P < 0.001) than those in the control group.

CONCLUSION: Combination of ¹³¹I-metuximab and TACE prolonged the survival time in patients with HCC compared with TACE alone. The combination treatment was safe and effective.

[Hematological toxicity of radioimmunotherpy with 90Y Ibritumomab]

Radioimmunotherapy with 90Y Ibritumomabu (Zevalin, BSP) is a new method of systemic radiotherapy applicable to B-cell lymphoma patients. It may be delivered as a short outpatient procedure, with few adverse effects other than hematological toxicity. In the paper, we present length and depth of cytopenias, together with the results of additional tests performed to reveal the possible pathomechanisms, based on 102 patients treated at the University Hospital in Krakow.

[Indications for radioimmunotherapy for patients with non-Hodgkin's lymphoma]

Radioimmunotherapy is a well-known treatment for non-Hodgkin's lymphoma. (90)yttrium (Y)-ibritumomab-tiuxetan consists of a radioisotope conjugated to a monoclonal anti-cluster of differentiation 20 antibody, which is targeted against B-lymphocytes. Initially the treatment indication was relapse of low-grade non-Hodgkin's lymphoma. However, (90)Y-ibritumomab-tiuxetan has later been used in clinical trials in the treatment of other types of non-Hodgkin's lymphoma and prior to stem cell transplantation. Based on the literature this systematic review aims to throw light on the future possibilities of radioimmunotherapy.

Radioimmunotherapy for NHL: Experience of90Y-Ibritumomab Tiuxetan in Clinical Practice

Radioimmunotherapy (RIT) is a novel treatment modality that combines the benefits of radiotherapy and immunotherapy, enabling multiple sites of disseminated disease to be treated simultaneously and effectively, while minimizing toxicity to normal tissues. 90Y-ibritumomab tiuxetan consists of the anti-CD20 monoclonal antibody (MAb) ibritumomab covalently linked to tiuxetan for chelation of 90Y for therapy. Early work established that a dose of 14.8 MBq/kg (0.4 mCi/kg) is safe and effective in patients with < 25% bone marrow involvement and adequate marrow reserves, as is a dose of 11.1 MBq/kg (0.3 mCi/kg) in patients with mild thrombocytopenia (platelet counts 100 x 10(9)-150 x 10(9)/l). To date, 5 clinical trials using 90Y-ibritumomab tiuxetan have been reported, one of which assessed the efficacy in rituximab-refractory patients with follicular non-Hodgkin's lymphoma (NHL) histology. Within the 54 follicular lymphoma patients, an overall response (OR) rate of 74% and a complete response (CR) rate of 15% were achieved, despite patients having received a median of 4 prior therapies and 73% having tumors > or = 5 cm in diameter. In addition, a major phase III randomized trial directly compared 90Y-ibritumomab tiuxetan with the unlabeled anti-CD20 MAb rituximab. Results from the randomized trial demonstrated that OR and CR rates were significantly higher with 90Y-ibritumomab tiuxetan, compared with rituximab (OR rate 80% vs. 56%, P = 0.002; CR rate 30% vs. 16%, P = 0.004). Time to progression (TTP) was 11.2 vs. 10.1 months (P = 0.173). Treatment was generally well tolerated; the primary toxicity associated with 90Y-ibritumomab tiuxetan therapy is reversible myelosuppression, which correlates with the degree of bone marrow involvement at baseline. In an integrated analysis of safety data from 5 90Y-ibritumomab tiuxetan studies, only 7% of patients were hospitalized due to infection during the treatment period. In addition, 90Y-ibritumomab tiuxetan therapy was not shown to increase the risk of developing secondary malignancies (myelodysplastic syndrome/acute myeloid leukemia), or preclude subsequent therapy upon relapse. Current investigations are focussing on the potential role of 90Y-ibritumomab tiuxetan earlier in the treatment algorithm, including as single-agent therapy for relapsed diffuse large B-cell lymphoma patients not eligible for transplantation, and consolidation treatment for low-grade NHL patients after first-line, alkylating agent-based therapy.

The Role of Nuclear Medicine in the Treatment of Non-Hodgkin's Lymphoma (NHL)

The emergence of radioimmunotherapy (RIT) provides a new therapeutic approach in which monoclonal antibodies directed against tumor-specific antigens are used to target therapeutic radioisotopes to sites of disseminated disease. The target cell is eliminated and adjacent tumor cells, to which antibody has not bound, are also killed. To date, 90Y-ibritumomab tiuxetan and 131I-tositumomab are the only FDA-approved, and most extensively studied, radioimmunoconjugates for RIT of non-Hodgkin's lymphoma (NHL). Both 90Y-ibritumomab tiuxetan and 131I-tositumomab utilize an anti-CD20 monoclonal antibody to target radioactivity to malignant B-cells. 90Y-ibritumomab tiuxetan emits pure therapeutic beta radiation, permitting outpatient treatment. The high energy of the beta particles emitted by 90Y (2.3 MeV) achieves a wide-ranging crossfire effect. Approximately 90% of the energy is deposited within 5 mm of the radiation source, which kills not only antibody-bound cells but also neighboring malignant cells within a diameter of up to 12 mm. In addition, the half-life of 90Y matches the in vivo biological half-life of the monoclonal antibody (64 h), with negligible excretion of 90Y in urine. With 90Y-ibritumomab tiuxetan, hematological adverse events correlate with the degree of bone marrow involvement and the bone marrow reserve, rather than with dosimetric parameters, and doses to normal organs and red marrow are well below the accepted limits of 20 Gy to normal organs and 3 Gy to red marrow. A dosing schedule based on patient weight and baseline platelet counts has therefore been developed, and dosimetry is not routinely required. 131I, the isotope used in tositumomab RIT, emits both therapeutic beta radiation and highly penetrating gamma emissions. The lower energy of the beta particles emitted by 131I (0.6 MeV) achieves a crossfire effect of up to 2 mm in diameter, which is used to treat tumors. The gamma radiation emitted by 131I allows both dosimetry and biodistribution studies to be performed; such studies are important because the rate of 131I-tositumomab clearance varies among individuals. Therefore, dosimetry must be performed in each patient before the therapeutic dose of 131I-tositumomab is administered. Similarly, because of this variability in 131I clearance, the dosage of 131I-tositumomab is calculated accordingly for each patient. 131I-tositumomab is a substrate for dehalogenases, which decouple the radioisotope from the antibody moiety, resulting in free, circulating 131I, which can accumulate in the thyroid. Patients who receive 131I-tositumomab therapy are usually hospitalized in radioprotection wards, and are treated by specially trained hospital staff. The administration of RIT requires an integrated team approach, involving nuclear medicine (or, in some countries, radiation oncology), hematology-oncology, nursing, radiopharmacy and radiation safety personnel. Effective collaboration between all members of the RIT team is essential to treatment success, and understanding the properties of these novel agents will facilitate their safe and effective administration.

Sequential cytarabine and alpha-particle immunotherapy with bismuth-213-lintuzumab (HuM195) for acute myeloid leukemia

PURPOSE

Lintuzumab (HuM195), a humanized anti-CD33 antibody, targets myeloid leukemia cells and has modest single-agent activity against acute myeloid leukemia (AML). To increase the potency of the antibody without the nonspecific cytotoxicity associated with β-emitters, the α-particle-emitting radionuclide bismuth-213 ((213)Bi) was conjugated to lintuzumab. This phase I/II trial was conducted to determine the maximum tolerated dose (MTD) and antileukemic effects of (213)Bi-lintuzumab, the first targeted α-emitter, after partially cytoreductive chemotherapy.

EXPERIMENTAL DESIGN

Thirty-one patients with newly diagnosed (n = 13) or relapsed/refractory (n = 18) AML (median age, 67 years; range, 37-80) were treated with cytarabine (200 mg/m(2)/d) for 5 days followed by (213)Bi-lintuzumab (18.5-46.25 MBq/kg).

RESULTS

The MTD of (213)Bi-lintuzumab was 37 MB/kg; myelosuppression lasting >35 days was dose limiting. Extramedullary toxicities were primarily limited to grade ≤2 events, including infusion-related reactions. Transient grade 3/4 liver function abnormalities were seen in five patients (16%). Treatment-related deaths occurred in 2 of 21 (10%) patients who received the MTD. Significant reductions in marrow blasts were seen at all dose levels. The median response duration was 6 months (range, 2-12). Biodistribution and pharmacokinetic studies suggested that saturation of available CD33 sites by (213)Bi-lintuzumab was achieved after partial cytoreduction with cytarabine.

CONCLUSIONS

Sequential administration of cytarabine and (213)Bi-lintuzumab is tolerable and can produce remissions in patients with AML.

Radioimmunotherapy of heavily pre-treated, non-Hodgkin's lymphoma patients: efficacy and safety in a routine setting

The aim of the present study waw to assess efficacy and safety of radio-immunotherapy with Zevalin (RIT-Z) in heavily pre-treated, rituximab-refractory patients.

PATIENTS AND METHODS

We studied 12 patients with indolent lymphoma and 7 with aggressive lymphoma. The median number of prior rituximab-containing treatments was 2; overall, 3 therapies had been previously given. Ten patients received RIT-Z as salvage therapy, 9 at high risk of relapse received RIT-Z as consolidation. Staging and follow-up were obtained by positron-emission tomography. Outcomes assessed were failure-free survival (FFS) and time to next treatment (TTNT).

RESULTS

Overall FFS and TTNT were 5 and 11 months, respectively; median follow-up 13 months. Major findings were i) no long-term remissions observed in 7 patients who had not responded to their most recent therapy and ii) lack of association between any pre-therapy variables analysed and outcomes. Different subgroups showed no difference in terms of toxicity.

CONCLUSION

We encourage the use of RIT-Z as a consolidation for pre-treated patients with both indolent and aggressive lymphoma.

Hypothyroidism: a growing complication of cancer treatment

Hypothyroidism is an often underreported complication of cancer treatment. With the growing number of biological and targeted therapies, hypothyroidism may become a more prevalent clinical problem. Signs and symptoms of hypothyroidism may be easily attributed to the cancer or cancer treatment, leading to unnecessary dose modifications or discontinuation of effective therapies. Furthermore, these symptoms have a negative effect on quality of life. Measurement of TSH levels in at-risk patients prior to initiating treatment and at regular intervals during treatment will allow early intervention and effective treatment of hypothyroidism.

Randomised Phase I/II trial assessing the safety and efficacy of radiolabelled anti-carcinoembryonic antigen I(131) KAb201 antibodies given intra-arterially or intravenously in patients with unresectable pancreatic adenocarcinoma

BACKGROUND

Advanced pancreatic cancer has a poor prognosis, and the current standard of care (gemcitabine based chemotherapy) provides a small survival advantage. However the drawback is the accompanying systemic toxicity, which targeted treatments may overcome. This study aimed to evaluate the safety and tolerability of KAb201, an anti-carcinoembryonic antigen monoclonal antibody, labelled with I(131) in pancreatic cancer (ISRCTN 16857581).

METHODS

Patients with histological/cytological proven inoperable adenocarcinoma of the head of pancreas were randomised to receive KAb 201 via either the intra-arterial or intravenous delivery route. The dose limiting toxicities within each group were determined. Patients were assessed for safety and efficacy and followed up until death.

RESULTS

Between February 2003 and July 2005, 25 patients were enrolled. Nineteen patients were randomised, 9 to the intravenous and 10 to the intra-arterial arms. In the intra-arterial arm, dose limiting toxicity was seen in 2/6 (33%) patients at 50 mCi whereas in the intravenous arm, dose limiting toxicity was noted in 1/6 patients at 50 mCi, but did not occur at 75 mCi (0/3).The overall response rate was 6% (1/18). Median overall survival was 5.2 months (95% confidence interval = 3.3 to 9 months), with no significant difference between the intravenous and intra-arterial arms (log rank test p = 0.79). One patient was still alive at the time of this analysis.

CONCLUSION

Dose limiting toxicity for KAb201 with I(131) by the intra-arterial route was 50 mCi, while dose limiting toxicity was not reached in the intravenous arm.

[Radioimmunotherapy of follicular lymphoma: a step towards cure?]

Advanced stage follicular lymphoma is incurable by conventional treatment. Important progress has been observed with the development of new therapies based on monoclonal antibodies and on the use of radioimmunotherapy (RIT) in the treatment of non-Hodgkin lymphomas (NHL). Rituximab in combination with chemotherapy in the upfront setting significantly improved treatment outcome as compared with chemotherapy alone. Different studies also indicate that RIT has an important role in the management of NHL and could be beneficial in combination with chemotherapy. These two new treatment options have clearly distinctive mechanisms of action, rituximab being an exclusively biological treatment and RIT adding targeted systemic radiation therapy. Both RIT and the unlabeled antibody treatments might be further improved by different strategies including repetition of RIT or combination of different antibodies. We present here our experience with RIT using 131I-tositumomab (Bexxar) and discuss different topics regarding RIT, like the use of different antibodies, the best choice of the radioisotope or the place of radio-imaging. From the therapeutic point of view, we argue that the debate should not be as to which one among antibody immunotherapy or RIT should be best added to chemotherapy, but that all three treatments might be optimally combined with the aim to get the highest chance of cure for advanced stage follicular lymphoma.

[Alpha-radioimmunotherapy: a review of recent developments]

The use of heavy particles in the treatment of cancer is increasing remarkably, whether with external radiation or using a vector such as an antibody in radioimmunotherapy. Recent pre-clinical and clinical developments of alpha-radioimmunotherapy have provided more interesting information in parallel of the use of high Linear Energy Transfer (LET) external irradiation. This review aims at presenting recent advances of this therapeutic approach, and at detailing the biological specificities of this kind of radiation.

Focal radiation fibrosis after radioimmunotherapy for follicular non-Hodgkin lymphoma

A 75-year-old man with relapsed follicular non-Hodgkin lymphoma confined to a solitary lung mass was treated with radioimmunotherapy (RIT) using yttrium 90-ibritumomab tiuxetan. Imaging with positron emission tomography/computed tomography showed a complete response 3 months after RIT. Thirteen months after RIT, his positron emission tomography/computed tomography scan showed a fluorodeoxyglucose-avid infiltrate in the area of the previous lung mass. Bronchoscopy revealed the area to be obstructed with fibrosis, and cytologic washings and brushings did not show lymphoma. The patient remains asymptomatic, and the fluorodeoxyglucoseavid pulmonary infiltrate was unchanged 19 months after RIT. In view of the lack of respiratory symptoms or progressive imaging abnormalities, we believe radiation fibrosis is the most likely etiology. Radiation-induced lung injury after therapy with yttrium 90 was previously reported in the setting of intraarterial microspheres used to treat inoperable hepatic tumors. This is the first case in which radiation-induced radiographic changes are reported after RIT for lymphoma.

Combining radioimmunotherapy with antihypoxia therapy 2-deoxy-D-glucose results in reduction of therapeutic efficacy

PURPOSE

The efficacy of solid tumor radioimmunotherapy is reduced by heterogeneous tumor distribution of the radionuclide, with dose mainly deposited in the normoxic region and by the relative radioresistance of hypoxic tumor cells. In an attempt to overcome these challenges, radioimmunotherapy was combined with 2-deoxy-d-glucose (2DG), a hypoxia-selective cytotoxic inhibitor of glucose metabolism.

EXPERIMENTAL DESIGN

In vitro toxicity of 2DG in LS174T cultures was tested using a colony-forming assay. The effect of combining 2DG with radioimmunotherapy in vivo was tested by administering radiolabeled anti-carcinoembryonic antigen antibody ([(131)I]A5B7 IgG1 whole monoclonal) to nude mice bearing s.c. LS174T tumors, followed by 10 daily injections of 2DG (2.0 g/kg). Tumors were measured to assess therapeutic efficacy.

RESULTS

Data from in vitro studies confirmed 2DG cytotoxicity in this cell line. Greater toxicity was observed under standard laboratory conditions and in hypoxic cultures than at intermediate, physiologically relevant levels of glucose and oxygen. Alone, 2DG had no effect on in vivo tumor growth (P = 0.377 compared with saline-treated controls). Combination of radioimmunotherapy with 2DG reduced the therapeutic effect of radioimmunotherapy (e.g., 150 microCi (131)I alone mean survival time, 48.33 +/- 16.83 days; combined with 2DG, 30.67 +/- 5.62 days, P = 0.038).

CONCLUSIONS

The combination investigated had a detrimental effect on survival. It is suggested that a cellular metabolic response to more aggressive therapy, previously reported in vitro, caused this. The results of this study have implications for the clinical application of combined cancer therapies with an antimetabolic modality component.

Therapy-related myelodysplastic syndrome and acute myeloid leukemia following initial treatment with chemotherapy plus radioimmunotherapy for indolent non-Hodgkin lymphoma

Patients with indolent non-Hodgkin lymphoma (I-NHL) often receive multiple courses of cytotoxic chemotherapy over several years. Radioimmunotherapy (RIT) has become an important part of treatment for relapsed patients and tositumomab/lodine I-131 tositumomab is a promising regimen currently being incorporated into first-line therapy. While treatment-related myelodysplasia (tMDS) and acute myeloid leukemia (tAML) are well-known, poor-prognosis complications of conventional chemotherapy and radiation therapy, they have not been previously observed as a consequence of initial treatment with RIT-based regimens. We describe four patients with tMDS/tAML who received a sequential chemotherapy and tositumomab/lodine I-131 tositumomab program as their initial and only lymphoma treatment. Our findings suggest that the potential risk of these important complications must be considered in the development of this novel therapeutic strategy in the first-line setting.

Combination therapy using gemcitabine and radioimmunotherapy in nude mice with small peritoneal metastases of colonic origin

INTRODUCTION

Gemcitabine has been shown to exert a radiosensitizing effect in various epithelial cancers. The aim of the present studies was to investigate whether the efficacy of radioimmunotherapy (RIT) using the (131)I-labeled anti-CEA monoclonal antibody (MAb) MN-14 could be enhanced by coadministration of gemcitabine in nude mice with small (1-3 mm) peritoneal metastases of colonic origin.

MATERIALS AND METHODS

Firstly, the maximum tolerated dose (MTD) of gemcitabine was determined, when administered intraperitoneally at two different dosing schedules (0.11-3.0 mg/mouse/administration on days 0, 3, 6, and 9, or 0.022-0.60 mg/mouse/administration on days 0, 1, 2, 3, and 4). In two separate therapy studies in which these two administration regimens were applied, the efficacy of gemcitabine monotherapy was compared to that of RIT alone (125 muCi (131)I-MN-14/mouse) or RIT combined with gemcitabine.

RESULTS

When administered every 3rd day for a total of 4 administrations, or daily for 5 consecutive days, the gemcitabine was considered safe at 0.33 mg/mouse/administration and 0.066 mg/mouse/administration, respectively. In the first therapy study, median survival of the control mice was 39 days. Gemcitabine monotherapy at 0.11 mg or 0.33 mg/mouse/administration every 3rd day (total, 4 administrations) resulted in a median survival of 52 and 57 days, respectively (p = 0.0003, compared to controls). RIT alone resulted in a median survival of 66 days (p < 0.0001, compared to controls). The combination of RIT and gemcitabine coadministration resulted in a median survival of 73 and 94 days, respectively (p = 0.12, for trend). In the second therapy study, median survival of the control mice was 48 days, which was similar to the median survival of the mice treated with daily administrations of gemcitabine monotherapy at 0.022 mg/mouse/administration on 5 consecutive days (49 days; p = 0.17). RIT alone resulted in a significantly improved median survival of 66 days (p= = 0.0010, compared to controls). Combination therapy using RIT and gemcitabine resulted in a median survival of 64 days, which did not differ significantly from the survival of the mice treated with RIT alone (p = 0.43).

CONCLUSIONS

At the dose regimens employed, gemcitabine did not enhance the efficacy of RIT of experimental small-volume peritoneal carcinomatosis of colonic origin.

Radiation Safety Guidelines for Radioimmunotherapy With Yttrium 90 Ibritumomab Tiuxetan

Radioimmunotherapy is a new cancer therapy that combines the cytotoxicity of radiation with the tumor-specific targeting of monoclonal antibodies. Yttrium 90 (Y-90) ibritumomab tiuxetan (Zevalin, IDEC Pharmaceuticals Corporation, San Diego, CA) is indicated for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma (NHL), including patients with rituximab-refractory follicular NHL. Y-90 ibritumomab tiuxetan requires only universal safety precautions and does not impose undue risks or radiation safety restrictions on patients or healthcare workers. The ibritumomab tiuxetan regimen can be administered safely in an outpatient setting. Nurses should become familiar with the necessary precautions in caring for patients treated with Y-90 ibritumomab tiuxetan, both to educate patients about safety issues and to minimize the risk of radiation exposure to staff and others.

Radioimmunotherapy for non-Hodgkin's lymphoma

OBJECTIVES

To describe the rationale for radioimmunotherapy as a treatment of non-Hodgkin's lymphoma. To present the similarities and differences in the two radioimmunotherapies and the nursing implications in caring for patients receiving these agents.

DATA SOURCES

Published literature and review of published clinical trials.

CONCLUSION

Radiolabeled monoclonal antibodies bind to specific antigens and provide a means of targeting tumor cells with cytotoxic radioactivity. The infusion of radiolabeled monoclonal antibodies requires an understanding of antibody therapy, radiation therapy, and principles of time, distance, and shielding.

IMPLICATIONS FOR NURSING PRACTICE

As the use of radioimmunotherapy grows, nurses must be aware of the background for, logistics of, and follow-up required for patients receiving this form of radiation treatment.

Multicenter Phase II Clinical Study of Iodine-131–Rituximab Radioimmunotherapy in Relapsed or Refractory Indolent Non-Hodgkin’s Lymphoma

Purpose

To evaluate efficacy and safety of iodine-131 (131I) –rituximab chimeric anti-CD20 antibody radioimmunotherapy in patients with relapsed or refractory indolent non-Hodgkin's lymphoma (NHL).

Patients and Methods

After a standard loading dose of rituximab 375 mg/m2, individualized dosimetry was performed by whole-body gamma imaging of a tracer activity of 131I-rituximab followed by administration of a therapeutic activity of 131I-rituximab to deliver an estimated whole-body radiation absorbed dose of 0.75 Gy.

Results

Ninety-one patients were entered onto the trial: 78 patients (86%) had follicular lymphoma, six patients (7%) had mucosa-associated lymphoid tissue/marginal zone lymphoma, and seven patients (8%) had small lymphocytic lymphoma. The objective overall response rate (ORR) was 76%, with 53% attaining a complete response (CR) or CR unconfirmed (CRu). Median duration of response for patients achieving CR/CRu was 20 v 7 months for those with a partial response (P = .0121). Median progression-free survival for the entire cohort was 13 months, with 14% remaining relapse free beyond 4 years. Median follow-up was 23 months, with a 4-year actuarial survival rate of 59% ± 10%. Toxicity was principally hematologic; grade 4 thrombocytopenia occurred in 4% and neutropenia occurred in 16% of patients, with nadirs at 6 to 7 weeks after treatment.

Conclusion

131I-rituximab radioimmunotherapy of relapsed or refractory indolent NHL achieves high ORR and CR rates with minimal toxicity.

Extravazation of therapeutic yttrium-90-ibritumomab tiuxetan (zevalin): a case report

The occurrence of radiation necrosis to the extravasation of therapeutic radionuclide-yttrium-90-ibritumomab tiuxetan-is described, as well as the subsequent steps taken to both address the occurrence and to prevent the re-occurrence of such an adverse event. Published reports on the extravasation of diagnostic and therapeutic radionuclides are reviewed, as are prevention and treatment protocols.