Gamma camera scans and pretreatment tumor volumes as predictors of response and progression after Y-90 anti-CD20 radioimmunotherapy

Priming radioimmunotherapy with external beam radiation in patients with relapsed low grade non-Hodgkin lymphoma

BACKGROUND

The aim of this study was to evaluate the outcomes of priming salvage radioimmunotherapy (RIT) with a low dose of external beam radiotherapy (EBRT) in patients with relapsed low grade non-Hodgkin lymphoma (LG-NHL).

METHODS

Patients who received salvage RIT with or without 2 × 2 Gy EBRT between March 2009 and February 2013 were retrospectively reviewed at a single institution. Planning target volume (PTV) for EBRT was created by adding a 1-2 cm expansion to the gross tumor volume depending on the anatomical location. Kaplan-Meier method via log-rank was employed to analyze the endpoints freedom from progression (FFP) and overall survival (OS).

RESULTS

We identified 22 patients who received salvage RIT without chemotherapy with a median follow up of 34 months. Of these, 9 (41%) patients were treated with EBRT immediately prior to RIT, and 13 (59%) received salvage RIT alone. Median FFP was not reached in patients who underwent combination treatment, while it was 9 months for patients treated with RIT alone (p = 0.02). OS for all patients at 36 months was 80.3% with no significant difference between the two groups (p = 0.88). On univariate analysis, the addition of EBRT was associated with improved FFP [hazard ratio (HR) = 4.17; 95% confidence interval (CI), 1.24-19.1; p = 0.02)]. No long term toxicities were reported in both groups.

CONCLUSIONS

RIT outcomes and effects were improved with addition of low-dose EBRT immediately prior to it, in the treatment of relapsed LG-NHL with no additional toxicity. This study is hypothesis-generating and the findings should be validated in prospective studies.

Does tumoral (111)In-ibritumomab accumulation correlate with therapeutic effect and outcome in relapsed or refractory low-grade B-cell lymphoma patients undergoing (90)Y-ibritumomab radioimmunotherapy?

OBJECTIVES

The aim of this study was to determine whether tumoral (111)In-ibritumomab accumulation on pre-treatment imaging correlates with therapeutic responses and progression-free survival (PFS) in patients with non-Hodgkin's lymphoma (NHL) undergoing (90)Y-ibritumomab radioimmunotherapy (RIT).

METHODS

This was a retrospective study of 39 patients with low-grade B-cell NHL treated with RIT. We classified the patients into positive and negative groups according to the presence or absence of tumoral (111)In-ibritumomab accumulation on pre-treatment (111)In-ibritumomab examinations. We then determined the correlation between the (111)In-ibritumomab imaging findings and the patients' therapeutic responses and PFS.

RESULTS

Tumoral (111)In-ibritumomab accumulation was positive in 64.1% and negative in 35.9% of the patients. The (111)In-positive patients had a significantly higher overall response rate (ORR) compared to the (111)In-negative patients (100.0% vs. 78.6%, p = 0.02). The (111)In-negative patients with advanced disease (stages III/IV) had a significantly lower ORR (40%) and a significantly higher rate of progressive disease (40.0%) compared to those of the (111)In-negative patients with limited disease (stages I/II) (100% and 0%, p = 0.009 each). However, these two groups had similar 2-year PFS rates (65.0% vs. 50.0%, p = 0.80).

CONCLUSIONS

(111)In-ibritumomab imaging findings seem to correlate with ORR and the progressive disease rate after RIT, but not with PFS.

KEY POINTS

All 39 NHL patients had tumoral accumulation on pretreatment FDG-PET/CT. 64.1% of NHL patients had tumoral accumulation on a pretreatment (111) In-ibritumomab examination. (90) Y-ibritumomab RIT resulted in high overall response and complete remission rates. (111) In-ibritumomab avidity of lymphoma lesions could predict a strong therapeutic effect. (111) In-ibritumomab imaging findings did not correlate with progression-free survival.

Theranostic applications of antibodies in oncology

Targeted therapies, including antibodies, are becoming increasingly important in cancer therapy. Important limitations, however, are that not every patient benefits from a specific antibody therapy and that responses could be short-lived due to acquired resistance. In addition, targeted therapies are quite expensive and are not completely devoid of side-effects. This urges the need for accurate patient selection and response monitoring. An important step towards personalizing antibody treatment could be the implementation of theranostics. Antibody theranostics combine the diagnostic and therapeutic potential of an antibody, thereby selecting those patients who are most likely to benefit from antibody treatment. This review focuses on the clinical application of theranostic antibodies in oncology. It provides detailed information concerning the suitability of antibodies for theranostics, the different types of theranostic tests available and summarizes the efficacy of theranostic antibodies used in current clinical practice. Advanced theranostic applications, including radiolabeled antibodies for non-invasive functional imagining, are also addressed. Finally, we discuss the importance of theranostics in the emerging field of personalized medicine and critically evaluate recent data to determine the best way to apply antibody theranostics in the future.

Efficacy and safety of yttrium-90 ibritumomab tiuxetan in Japanese patients with non-Hodgkin lymphoma

PURPOSE

The aim of this study was to evaluate the efficacy and side effects of radioimmunotherapies with Zevalin(®) (RIT-Z) in Japanese patients with low-grade B-cell non-Hodgkin lymphoma (NHL).

MATERIALS AND METHODS

Sixty-two patients with NHL were enrolled. Based on histology, 49 of the patients had follicular lymphoma and 23 had other lesions. The response was assessed at 8-12 weeks after RIT-Z injection with PET/CT.

RESULTS

The overall response rate was 85 %. Thirty-seven (60 %) patients achieved complete remission, 16 (26 %) had partial remission, 4 (6 %) had stable disease, and 5 (8 %) had progressive disease. There was a significant correlation between the response to RIT-Z, frequency of chemotherapy, and history of prior treatment with fludarabine. There was no significant difference in efficacy according to lymphoma type, years since last chemotherapy, patient age, or disease stage at RIT-Z. Thrombocytopenia of grade 4 was significantly correlated with disease stage at RIT-Z and history of prior treatment with fludarabine. There was also no significant correlation between hematotoxicity and lymphoma type, frequency of chemotherapy, years since last chemotherapy, patient age, or history of bone marrow transplant. Anemia was significantly correlated with frequency of chemotherapy, history of bone marrow transplant, and history of prior treatment with fludarabine.

CONCLUSIONS

The response rate was high, and we were able to decrease the hematologic side effects by using RIT-Z earlier.

Outcomes of patients with non-Hodgkin's lymphoma treated with Bexxar with or without external-beam radiotherapy

PURPOSE

To compare the efficacy and toxicity of external-beam radiotherapy (EBRT) to sites of bulky lymphadenopathy in patients with chemotherapy-refractory low-grade non-Hodgkin's lymphoma (NHL) immediately before receiving Bexxar (tositumomab and (131)I) vs. in patients receiving Bexxar alone for nonbulky disease.

METHODS AND MATERIALS

Nineteen patients with chemotherapy-refractory NHL were treated with Bexxar at our institution (University of Florida, Gainesville, FL) from 2005 to 2008. Seventeen patients had Grade 1-2 follicular lymphoma. Ten patients received a median of 20 Gy in 10 fractions to the areas of clinical involvement, immediately followed by Bexxar (EBRT + Bexxar); 9 patients received Bexxar alone. The median tumor sizes before EBRT + Bexxar and Bexxar alone were 4.8 cm and 3.3 cm, respectively. All 5 patients with a tumor diameter >5 cm were treated with EBRT + Bexxar. A univariate analysis of prognostic factors for progression-free survival (PFS) was performed.

RESULTS

The median follow-up was 2.3 years for all patients and 3.1 years for 12 patients alive at last follow-up. Of all patients, 79% had a partial or complete response; 4 of the 8 responders in the EBRT + Bexxar group achieved a durable response of over 2 years, including 3 of the 5 with tumors >5 cm. Three of 9 patients treated with Bexxar alone achieved a durable response over 2 years. Actuarial estimates of 3-year overall survival and PFS for EBRT + Bexxar and Bexxar alone were 69% and 38% and 62% and 33%, respectively. The median time to recurrence after EBRT + Bexxar and Bexxar alone was 9 months. Having fewer than 4 involved lymph-node regions was associated with superior PFS at 3 years (63% vs. 18%). There was no Grade 4 or 5 complications.

CONCLUSIONS

Adding EBRT immediately before Bexxar produced PFS equivalent to that with Bexxar alone, despite bulkier disease. Hematologic toxicity was not worsened. EBRT combined with Bexxar adds a safe and effective therapeutic treatment for managing recurrent low-grade follicular NHL.

Yttrium-90 ibritumomab tiuxetan as a single agent in patients with pretreated B-cell lymphoma: evaluation of the long-term outcome

BACKGROUND

Based on historical data on the role of radioimmunotherapy (RIT) in pretreated non-Hodgkin lymphoma, we reviewed our hospital's clinical database.

PATIENTS AND METHODS

Between 2005 and 2008, 57 patients previously treated with at least 1 rituximab-containing chemotherapy were treated with Yttrium-90-labeled ibritumomab tiuxetan ((90)Y-IT). The median number of pretreatments was 3 (range, 1-9 pretreatments). A total of 46 patients had stage III/IV disease (31 with bone marrow involvement); 6 had bulky disease. According to histology, 53 were follicular lymphoma (FL), 2 were marginal zone lymphoma, and 2 were small lymphocytic lymphoma.

RESULTS

Overall response rate was 93% (53 of 57); complete response (CR) rate was 70% (40 of 57). Twenty-six of 40 patients (65%) who obtained a CR are in continuous CR (CCR) with a median follow-up of 20 months (range, 10-42 months); 4 of them still maintain their CCR after 36 months. All patients achieving a CCR had FL, and 21 of them with stage III/IV disease; 12 of 26 had been heavily pretreated (>or= 3 previous treatments), and 2 had had autologous stem cell transplantation. Toxicity was primarily hematologic and mostly transient; no grade 4 extrahematologic toxicity was observed.

CONCLUSION

This study confirms the safety and high efficacy of (90)Y-IT RIT in heavily pretreated FL patients, with the possibility of having a subset of long-term responders.

90Y-ibritumomab therapy in refractory non-Hodgkin's lymphoma: observations from 111In-ibritumomab pretreatment imaging

Radioimmunotherapy is an effective treatment for non-Hodgkin's lymphoma (NHL). 90Y-ibritumomab is an antibody targeting CD20 receptors on the surface of lymphocytes. We present observations from our clinical experience with 90Y-ibritumomab in the management of NHL.

METHODS

This was a retrospective study of 28 NHL patients treated with 90Y-ibritumomab. There were 21 men and 7 women, 36-85 y old. A diagnostic dose of 111In-ibritumomab was administered on day 0, and imaging followed immediately and at 24, 48, and 72 h. The doses of 90Y-ibritumomab ranged from 629 to 1,258 MBq (17-34 mCi). Outcomes were compared with the findings of the 111In-ibritumomab scans.

RESULTS

90Y-ibritumomab induced objective responses in 22 of 28 patients. A complete response was noted in 9 patients, a partial response in 9 patients, and a mixed response in 4 patients. Three patients had stable disease, and 3 patients had disease progression. 111In-ibritumomab findings were positive in 19 patients and negative in 9 patients. A complete response was noted in 2 of 19 patients with positive findings and 7 of 9 with negative findings. A partial response was seen in 7 of 19 patients with positive findings and 1 of 9 with negative findings. Disease progression was observed in 3 of 19 patients with positive findings and 0 of 9 with negative findings. The remaining patients had a mixed response or no changes.

CONCLUSION

A higher rate of complete response after 90Y-ibritumomab treatment was seen in patients with negative 111In-ibritumomab findings, whereas a higher rate of disease progression despite therapy was noted in patients with positive 111In-ibritumomab findings. This observation suggests that patients with bulky disease may require more aggressive management.

Study of radiolabeled indium-111 and yttrium-90 ibritumomab tiuxetan in primary central nervous system lymphoma

BACKGROUND

Therapeutic options for refractory or recurrent primary central nervous system lymphoma (PCNSL) are limited. The blood-brain barrier makes many agents used in systemic lymphomas ineffective in CNS lymphomas. The objective of this study was to determine whether intravenous radioimmunotherapy using anti-CD20 antibody can be delivered to PCNSL.

METHODS

This was a single-institution prospective study. Indium-111 ibritumomab tiuxetan was used for imaging and dosimetry. Yttrium-90 ibritumomab tiuxetan at doses of 0.3 to 0.4 mCi/kg were subsequently given for the treatment of recurrent or refractory PCNSL. 111In data were used to estimate radiation doses to lesions delivered by 90Y ibritumomab tiuxetan therapy.

RESULTS

Six patients (4 men, 2 women) with a median age of 60 years and median Karnofsky performance status of 70 received both indium-111 and yttrium-90 ibritumomab tiuxetan. The median absorbed dose delivered to the CNS lymphoma was 701 cGy compared with 70 cGy to normal brain. The median progression-free and overall survival times were 6.8 weeks and 14.3 weeks, respectively.

CONCLUSIONS

The results from this study suggest that it may be feasible to deliver radiolabeled monoclonal anti-CD20 antibodies as a component of therapy for PCNSL.

Is There a Role for Pelvic Irradiation in Localized Prostate Adenocarcinoma? Preliminary Results of GETUG-01

Purpose

To assess the benefit and toxicity and quality-of-life (QOL) outcomes of pelvic nodes irradiation in nonmetastatic prostate carcinoma patients.

Patients and Methods

Between December 1998 and June 2004, 444 patients with T1b-T3, N0 pNx, M0 prostate carcinoma were randomly assigned to either pelvic and prostate radiotherapy or prostate radiotherapy only. Patients were stratified according to the prognostic factor of lymph node involvement (LNI). Short-term 6-month neoadjuvant and concomitant hormonal therapy was allowed only for patients in the high-risk group. The pelvic dose was 46 Gy. The total dose recommended to the prostate was changed during the course of the study from 66 Gy to 70 Gy. Criteria for progression-free survival (PFS) included biologic prostate-specific antigen recurrences or a local or metastatic evolution. Acute and late toxicities were recorded according to the Radiation Therapy Oncology Group and Late Effects in Normal Tissues Subjective, Objective, Management, and Analytic scales, respectively. The QOL outcome was recorded with the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30, the International Prostatic Symptom Score, and the Sexual Function Index scales.

Results

With a 42.1-month median follow-up time, the 5-year PFS and overall survival were similar in the two treatment arms for the whole series and for each stratified group. On multivariate analysis, low LNI risk and hormonal therapy were statistically associated with increased PFS. However, subgroup analyses based on these factors did not show any benefit for pelvic irradiation. There were no significant differences in acute and late digestive toxicities and in QOL outcomes.

Conclusion

Pelvic node irradiation was well tolerated but did not improve PFS.

Radioimmunotherapy as a Therapeutic Option for Non-Hodgkin’s Lymphoma

Radioimmunotherapy (RIT) represents a relatively new antibody-based radiopharmaceutical treatment for patients with various kinds of tumors. Although the field has a long history of preclinical and clinical investigations using many different agents, to date, only 2 of these immunologically targeted radiopharmaceuticals have been cleared for commercial sale. Both of these agents ((90)Y-ibritumomab tiuxetan or "Zevalin" [Biogen-Idec, Boston, MA] and (131)I-tositumomab or "Bexxar" [GlaxoSmithKline Research, Triangle Park, NC]) are directed against the CD20 surface antigen found on normal mature B cells and greater than 95% of B-cell non-Hodgkin lymphoma (NHL). Both compounds produce similar impressive clinical outcomes (approximately 20%-40% complete response rates and 60%-80% overall response rates for patients with indolent B-cell NHL). Current protocol-based investigations of anti-CD20 RIT relate to new clinical uses and new CD20(+) targets.

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.

Technological advances in radioimmunotherapy

Radioimmunotherapy (RIT) is a method of selectively delivering radionuclides with toxic emissions to cancer cells, while reducing the dose to normal tissues. Although primary tumours can often be treated successfully with external beam radiotherapy or surgery, metastases often escape detection and treatment, leading to therapy failure, and these can be treated with systemic targeted therapies such as RIT. This review describes more recent developments in the field, including both technological developments from the laboratory and increasingly encouraging findings from clinical studies.

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.

Radioimmunotherapy in a radiation oncology environment: building a multi-specialty team

Radioimmunotherapy (RIT) is a new branch of radiation medicine in which antibodies specific for tumor-associated antigens are linked to radioactive atoms to provide biologically targeted short-range molecular radiotherapy. Two such biologically targeted radiopharmaceuticals have been approved for commercial use in the last few years. Y-90 ibritumomab tiuxetan (Zevalin) and I-131 tositumomab (Bexxar) both recognize the CD-20 surface antigen found on normal and malignant B cells. Both of these compounds produce impressive clinical results when used in the management of indolent, refractory, and transformed CD-20+ B-cell non-Hodgkin's lymphoma, but the unsealed sources involved in this class of compounds also require new types of patient care coordination and patient/environmental safety procedures. Because these multifunctional compounds are ideally administered through a multi-departmental team approach, the planning process to initiate and direct such a team is quite important. This article reviews some of the key processes that may be necessary to establish a successful clinical RIT team. The manuscript highlights the important roles that the radiation oncology team members may play in this multi-department enterprise.

Iodine-131 tositumomab (Bexxar) in a radiation oncology environment

Iodine-131 (I-131) tositumomab (Bexxar; GlaxoSmithKline, Research Triangle Park, NC) is one of two recently approved radiolabeled antibodies directed against the CD20 surface antigen found on normal B cells and in more than 95% of B cell non-Hodgkin's lymphoma. The compound itself is formulated as an IgG2a immunoglobulin radiolabeled with the mixed beta/gamma emitter I-131. Multicenter clinical trials have repeatedly shown impressive clinical responses (20-40% complete response rates and 60-80% overall response rates) in the patient groups for whom this treatment is indicated. Treatment-related toxicity is generally extremely mild and typically involves only reversible hematopoietic suppression and (in some cases) a risk of treatment-induced hypothyroidism. Owing to the radiation safety concerns necessitated by the clinical use of this targeted radiopharmaceutical, it is important for radiation oncology departments wishing to participate in the care of these patients to establish methodologies and standard operating procedures for safe and efficient departmental use. This summary reviews the pertinent background information related to the current clinical experience with I-131 tositumomab and highlights some of the major opportunities for the participation of radiation oncology in the patient evaluation and treatment process. I-131 tositumomab provides an excellent example of the way in which the increasingly important new field of "targeted therapy" intersects with the practice of clinical radiotherapy. The author contends that it will be worth the time and effort involved in establishing a firm basis for the development of a comprehensive program for systemic targeted radiopharmaceutical therapies (STaRT) within the radiation medicine domain.

Radioimmunotherapy for non-Hodgkin's lymphoma: a review for radiation oncologists

PURPOSE

The aim of this study was to review advances in radioimmunotherapy (RIT) for non-Hodgkin's lymphoma (NHL) and to discuss the role of the radiation oncologist in administering this important new form of biologically targeted radiotherapy.

METHODS AND MATERIALS

A review of articles and abstracts on the clinical efficacy, safety, and radiation safety of yttrium Y 90 (90Y) ibritumomab tiuxetan (Zevalin) and iodine I 131 tositumomab (Bexxar) was performed.

RESULTS

The clinical efficacy of RIT in NHL has been shown in numerous clinical trials of 90Y ibritumomab tiuxetan and 131I tositumomab. Both agents have produced significant responses in patients with low-grade, follicular, or transformed NHL, including patients with disease that had not responded or had responded poorly to previous chemotherapy or immunotherapy. Reversible toxicities such as neutropenia, thrombocytopenia, and anemia are the most common adverse events with both agents.

CONCLUSIONS

Radioimmunotherapy is safe and effective in many patients with B-cell NHL. 90Y ibritumomab tiuxetan and 131I tositumomab can produce clinically meaningful and durable responses even in patients in whom chemotherapy has failed. Treatment with RIT requires a multispecialty approach and close communication between the radiation oncologist and other members of the treatment team. The radiation oncologist plays an important role in treating patients with RIT and monitoring them for responses and adverse events after treatment.

Controversies in Follicular Lymphoma: “Who, What, When, Where, and Why?” (Not Necessarily in That Order!)

Follicular lymphoma (FL) is the most common subtype of indolent lymphoma. Specific “facts” about FL that were generated by past research and have been passed down as dogma to a majority of practicing oncologists over the past 20 to 30 years that need to be revisited, include: (1) do not initiate therapy soon after diagnosis in asymptomatic, advanced-stage patients since it does not change outcome; (2) initiate therapy with single-agent oral alkylators when intervention needed and “save” more aggressive combination chemotherapy for “later” since the standard chemotherapy regimen used did not seem to impact survival; (3) FL is an incurable disease and palliation of symptoms was an acceptable approach to the expected pattern of repeated relapses; (4) transformation of FL is independent of the type or timing of therapies received by a patient; (5) median overall survival (OS) for FL patients is 8–10 years. Although the heterogeneity of FL will never change, we are developing the scientific tools to identify and better understand the biologic and genetic features associated with its clinical variability. In the current exciting era of targeted therapies (e.g., rituximab, radioimmunoconjugates) and novel treatment approaches demonstrating an improvement in treatment outcomes (e.g., disease-free survival and OS), our old beliefs and historically accepted dogma need to be retested and revitalized. The optimal combination(s) of old and new agents and the optimal timing of when to initiate and how to sequence specific therapies will require data from well-designed clinical trials that should include important correlative laboratory studies.