Ola Lindén

Dose-Fractionated Radioimmunotherapy in Non-Hodgkin's Lymphoma Using DOTA-Conjugated, 90Y-Radiolabeled, Humanized Anti-CD22 Monoclonal Antibody, Epratuzumab.

Purpose: Fractionated radioimmunotherapy may improve therapeutic outcome by decreasing heterogeneity of the dose delivered to the tumor and by decreasing hematologic toxicity, thereby allowing an increased amount of radionuclide to be administered. Because humanized anti-CD22 epratuzumab can be given repeatedly, a single-center study was conducted to establish the feasibility, safety, optimal dosing, and preliminary efficacy of weekly administrations of 90Y-labeled 1,4,7,10-tetra-azacyclodecane-N,N′,N″,N‴-tetraacetic acid–conjugated epratuzumab. Experimental Design: Cohorts of three to six patients with B-cell lymphoma received 185 MBq/m2 [90Y]epratuzumab with unconjugated epratuzumab (total protein dose 1.5 mg/kg) once weekly for two to four infusions, with [111In]epratuzumab coadministered at first infusion for scintigraphic imaging and dosimetry. Results: Sixteen patients received treatment without significant infusional reactions. The overall objective response rate was 62% (95% confidence interval, 39-86%) in both indolent (75%) and aggressive disease (50%). Complete responses (CR/CRu) occurred in 25% of patients and were durable (event-free survival, 14-41 months). Two patients receiving four infusions had hematologic dose-limiting toxicity. Serum epratuzumab levels increased with each weekly dose. Of 13 patients with tumor cell CD22 expression determined by flow cytometry, seven of eight with strongly positive results had objective responses, versus one of five with negative or weakly positive results (P = 0.032). Conclusions: Radioimmunotherapy with weekly 185 MBq/m2 [90Y]epratuzumab achieved a high objective response rate (62%) across lymphoma subtypes, including durable CRs. The findings that three weekly infusions (555 MBq/m2, total dose) can be administered safely with only minor toxicity, that antibody levels increased during treatment weeks, and that therapeutic response predominantly occurs in patients with unequivocal CD22 tumor expression provide guidance for future studies.

Clinical radionuclide therapy dosimetry: the quest for the "Holy Gray".

IntroductionRadionuclide therapy has distinct similarities to, but also profound differences from external radiotherapy.ReviewThis review discusses techniques and results of previously developed dosimetry methods in thyroid carcinoma, neuro-endocrine tumours, solid tumours and lymphoma. In each case, emphasis is placed on the level of evidence and practical applicability. Although dosimetry has been of enormous value in the preclinical phase of radiopharmaceutical development, its clinical use to optimise administered activity on an individual patient basis has been less evident. In phase I and II trials, dosimetry may be considered an inherent part of therapy to establish the maximum tolerated dose and dose-response relationship. To prove that dosimetry-based radionuclide therapy is of additional benefit over fixed dosing or dosing per kilogram body weight, prospective randomised phase III trials with appropriate end points have to be undertaken. Data in the literature which underscore the potential of dosimetry to avoid under- and overdosing and to standardise radionuclide therapy methods internationally are very scarce.DevelopmentsIn each section, particular developments and insights into these therapies are related to opportunities for dosimetry. The recent developments in PET and PET/CT imaging, including micro-devices for animal research, and molecular medicine provide major challenges for innovative therapy and dosimetry techniques. Furthermore, the increasing scientific interest in the radiobiological features specific to radionuclide therapy will advance our ability to administer this treatment modality optimally.

EANM Dosimetry Committee guidelines for bone marrow and whole-body dosimetry.

IntroductionThe level of administered activity in radionuclide therapy is often limited by haematological toxicity resulting from the absorbed dose delivered to the bone marrow. The purpose of these EANM guidelines is to provide advice to scientists and clinicians on data acquisition and data analysis related to bone-marrow and whole-body dosimetry.Materials and methodsThe guidelines are divided into sections “Data acquisition” and “Data analysis”. The Data acquisition section provides advice on the measurements required for accurate dosimetry including blood samples, quantitative imaging and/or whole-body measurements with a single probe. Issues specific to given radiopharmaceuticals are considered. The Data analysis section provides advice on the calculation of absorbed doses to the whole body and the bone marrow. The total absorbed dose to the bone marrow consists of contributions from activity in the bone marrow itself (self-absorbed dose) and the cross-absorbed dose to the bone marrow from activity in bone, larger organs and the remainder of the body.ConclusionAs radionuclide therapy enters an era where patient-specific dosimetry is used to guide treatments, accurate bone-marrow and whole-body dosimetry will become an essential element of treatment planning. We hope that these guidelines will provide a basis for the optimization and standardization of the treatment of cancer with radiopharmaceuticals, which will facilitate single- and multi-centre radionuclide therapy studies.

Results of a phase I/II study of ocrelizumab, a fully humanized anti-CD20 mAb, in patients with relapsed/refractory follicular lymphoma

BACKGROUND Ocrelizumab is a humanized anti-CD20 antibody with increased antibody-dependent cellular cytotoxicity compared with rituximab. This phase I/II study evaluated its safety and efficacy in patients with relapsed/refractory follicular lymphoma (FL) after prior rituximab therapy. DESIGN AND METHODS Forty-seven patients were treated in three dose cohorts and received eight infusions every 3 weeks: cohort A, 200 mg/m(2) (n = 15); cohort B, 375 mg/m(2) (n = 16); cohort C, first dose 375 mg/m(2), seven subsequent doses of 750 mg/m(2) (n = 16). Patients were assessed for safety, efficacy, pharmacodynamics and pharmacokinetics. RESULTS The median patient age was 58 years, the majority had Ann Arbor stage III/IV disease and had received a median of 2 (range 1-6) prior regimens. Ocrelizumab was well tolerated with grade 3/4 toxicity occurring in 9% of patients. The most common toxicity was infusion-related reactions (74% patients), all grade 1/2 except one grade 3 event. The objective response rate was 38% and was similar in patients with low-affinity and high-affinity variants of the Fcgamma receptor IIIa (FcgammaRIIIa). With follow-up of approximately 28 months, the median progression-free survival was 11.4 months. CONCLUSION Ocrelizumab demonstrated activity in patients with relapsed/refractory FL following prior rituximab treatment, with safety similar to rituximab although adverse events appeared milder.

90Yttrium-Ibritumomab-Tiuxetan as First-Line Treatment for Follicular Lymphoma: 30 Months of Follow-Up Data From an International Multicenter Phase II Clinical Trial

PURPOSE We report on a multicenter phase II trial of (90)yttrium-ibritumomab-tiuxetan ((90)YIT) as first-line stand-alone therapy for patients with follicular lymphoma (FL). PATIENTS AND METHODS Fifty-nine patients with CD20(+) FL grade 1 to 3a in stages II, III, or IV, age 50 years old or older requiring therapy were enrolled. They received (90)YIT according to standard procedure. If complete response (CR) or unconfirmed complete response (CRu) without evidence for minimal residual disease (MRD) 6 months after application of (90)YIT was achieved, patients were observed without further intervention. The same applied to patients with partial response (PR) or with stable disease (SD). Patients with CR but with persisting MRD were to receive a consolidation treatment with rituximab. Primary end point was the clinical and molecular response rate. Secondary end points were time to progression, safety, and tolerability. RESULTS Six months after treatment with (90)YIT, 56% of the patients showed a CR or CRu and 31% achieved a PR. After a median follow-up of 30.6 months, the progression-free survival (PFS) was 26 months. There was a trend for shorter PFS in patients with increased lactate dehydrogenase (LDH). Of the 26 patients who had CR 12 months after (90)YIT, only three had relapsed. Median time to next treatment has not been reached. The most common toxicities were transient thrombocytopenia and leukocytopenia. Nonhematologic toxicities never exceeded grade 2 according to Common Terminology Criteria for Adverse Events (CTCAE v2.0). CONCLUSION (90)YIT is well tolerated and achieves high response rates. Patients with increased LDH tend to relapse earlier, and individuals in remission 1 year after (90)YIT appear to have long- lasting responses.

Regression of cervical spinal cord compression in a patient with chordoma following treatment with cetuximab and gefitinib

Regression of cervical spinal cord compression in a patient with chordoma following treatment with cetuximab and gefitinib

90Y Bremsstrahlung Imaging for Absorbed-Dose Assessment in High-Dose Radioimmunotherapy

This feasibility study demonstrates 90Y quantitative bremsstrahlung imaging of patients undergoing high-dose myeloablative 90Y-ibritumomab treatment. Methods: The study includes pretherapy 111In SPECT/CT and planar whole-body (WB) imaging at 7 d and therapy 90Y SPECT/CT at 6 d and 90Y WB imaging at 1 d. Time–activity curves and organ-absorbed doses derived from 90Y SPECT images were compared with pretherapy 111In estimates. Organ activities derived from 90Y WB images at the first day were compared with corresponding pretherapy estimates. Results: Pretherapy 111In images from 3 patients were similar to the 90Y images. Differences between absorbed-dose estimates from pretherapy 111In and 90Y therapy were within 25%, except for the lungs. Corresponding activity differences derived from WB images were within 25%. Differences were ascribed to incomplete compensation methods and real differences in pharmacokinetics between pretherapy and therapy. Conclusion: Quantitative bremsstrahlung imaging to estimate organ activities and absorbed doses is feasible.

T Cells in Tumors and Blood Predict Outcome in Follicular Lymphoma Treated with Rituximab

Purpose: T cells influence outcome in follicular lymphoma, but their contributions seem to be modified by therapy. Their impact in patients receiving rituximab without chemotherapy is unknown. Experimental Design: Using flow cytometry, we evaluated the T cells in tumors and/or blood in a total of 250 follicular lymphoma patients included in two Nordic Lymphoma Group randomized trials that compared single rituximab with IFN-α2a–rituximab combinations. Results: In univariate analysis, higher levels of CD3+, CD4+, and CD8+ T cells in both tumors and blood correlated with superior treatment responses, and in multivariate analysis, tumor-CD3+ (P = 0.011) and blood-CD4+ (P = 0.029) cells were independent. CD4+ cells were favorable regardless of treatment arm, but CD8+ cells were favorable only in patients treated with single rituximab, because IFN-α2a improved responses especially in patients with low CD8+ cell levels. Higher levels of blood-CD3+ (P = 0.003) and blood-CD4+ (P = 0.046) cells predicted longer overall survival, and higher levels of blood-CD8+ cells longer times to next treatment (P = 0.046). Conclusions: We conclude that therapeutic effects of rituximab are augmented by tumor-associated T cells for rapid responses and by systemic T cells for sustained responses. CD4+ and CD8+ cells are both favorable in patients treated with rituximab. IFN-α2a abrogates the negative impact of few CD8+ cells. Clin Cancer Res; 17(12); 4136–44. ©2011 AACR.

Follicular lymphoma in Sweden: nationwide improved survival in the rituximab era, particularly in elderly women - a Swedish Lymphoma Registry study.

Treatment for follicular lymphoma (FL) improved with rituximab. In Sweden, first-line rituximab was gradually introduced between 2003 and 2007, with regional differences. The first national guidelines for FL were published in November 2007, recommending rituximab in first-line therapy. Using the population-based Swedish Lymphoma Registry, 2641 patients diagnosed with FL from 2000 to 2010 were identified and characterized by year and region of diagnosis, age (median, 65 years), gender (50% men), first-line therapy and clinical risk factors. Overall and relative survivals were estimated by calendar periods (2000–2002, 2003–2007 and 2008–2010) and region of diagnosis. With each period, first-line rituximab use and survival increased. Survival was superior in regions where rituximab was quickly adopted and inferior where slowly adopted. These differences were independent in multivariable analyses. Ten-year relative survival for patients diagnosed 2003–2010 was 92%, 83%, 78% and 64% in the age groups 18–49, 50–59, 60–69 and ⩾70, respectively. With increasing rituximab use, male sex emerged as an adverse factor. Survival improved in all patient categories, particularly in elderly women. The introduction and the establishment of rituximab have led to a nationwide improvement in FL survival. However, rituximab might be inadequately dosed in younger women and men of all ages.

Time dependence of the activity concentration ratio of red marrow to blood and implications for red marrow dosimetry.

The method for red marrow dosimetry in radioimmunotherapy, in the absence of specific activity uptake in red marrow, is based on the activity measured in the blood or plasma. The activity concentration ratio of red marrow to blood is then assumed to be constant. The aim of the current study was to determine whether this ratio varies with time after injection.