Long-term follow up of rates of secondary malignancy and late relapse of two trials using radioimmunotherapy consolidation following induction chemotherapy for previously untreated indolent lymphoma

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.

Myeloid Toxicity of Radionuclide Cancer Therapy

Emergent genomic analytic techniques in patients with cancer offer the potential to define the risk of myelo dysplastic syndrome (MDS) and acute leukemia (AL) manifesting following targeted radionuclide therapy of metastatic lymphoma, neuroendocrine tumors (NETs), and prostate cancer. Characterization of the genetic profile will allow risk stratification of patients before theranostic radionuclide management of advanced cancers and offers the opportunity to minimize toxicity while preserving optimal individualized efficacy in the practice of personalized precision nuclear oncology. Our review of a single-center experience of prospective radionuclide theranostic management of metastatic non-Hodgkin lymphoma (NHL), NETs, and castration-resistant prostate cancer (metastatic castrate-resistant prostate cancer [mCRPC]) over the past decade, and comparison with published studies, shows that while the risk of significant myelotoxicity is generally low, at <3%, the consequences in the small minority of patients who develop MDS or AL are substantial, and survival is poor. Timely identification of patients at heightened risk of hematologic toxic complication, using novel genomic technology before institution of radionuclide therapy, will facilitate amelioration of myelotoxicity. In current clinical practice, the minimal hematological toxicity of chemo-free theranostic management of advanced cancer is significantly less compared with newly adopted chemotherapy -immunotherapy regimens, and the financial toxicity associated with these novel agents is avoided.

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.

Consolidation with 90 Yttrium-ibritumomab tiuxetan after bendamustine and rituximab for relapsed follicular lymphoma

Bendamustine and rituximab (BR) are widely used in patients with follicular lymphoma (FL) previously treated with conventional immunochemotherapy, but the role of consolidation radioimmunotherapy in these patients is unknown. This study evaluated the efficacy and safety of consolidation with ⁹⁰ Yttrium-ibritumomab tiuxetan (⁹⁰ Y-IT) after re-induction therapy with BR in patients with previously treated FL. This study included adult patients with relapsed FL who had undergone one or two prior therapies. Re-induction therapy with BR was administered every 4 weeks up to 4-6 cycles. If patients achieved at least partial response, ⁹⁰ Y-IT was administered as consolidation therapy. The primary endpoint was 2-year progression-free survival (PFS) after consolidation. A total of 24 FL patients (median age 60 years) who had undergone one (n = 17) or two (n = 7) prior treatments received BR. After BR therapy, 22 patients proceeded to consolidation with ⁹⁰ Y-IT, resulting in an overall 88% response rate to the protocol treatment. Within a median observation period of 46.8 months, the estimated 2-year PFS rate after the consolidation among the 22 patients receiving ⁹⁰ Y-IT was 59% (95% confidence interval [CI], 38%-77%). Patients whose remission after previous treatment had lasted ≥2 years had a significantly higher 2-year PFS rate than patients whose remission after previous treatment had been <2 years (68% vs. 33%, Wilcoxon p = 0.0211). Major adverse events during the protocol treatment and within 2 years after the consolidation were hematological toxicities, but they were generally acceptable. Consequently, the estimated 2-year overall survival after the consolidation was 95% (95% CI, 74%-99%). In conclusion, in a subset of patients with previously treated FL, ⁹⁰ Y-IT consolidation after BR re-induction conferred a durable remission, indicating that consolidation therapy using ⁹⁰ Y-IT may be a novel therapeutic option for patients with relapsed FL (UMIN000008793).

Radioimmunotherapy as the first line of treatment in non-Hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) is the most common hematologic malignancy. The estimated deaths and new cases of NHL in the USA in 2018 have reached 19,910 and 74,680, respectively, with 5-year survival rate of 71%. Therapeutic interventions for NHL consist of chemotherapy, radiation therapy and immunotherapy. Radioimmunotherapy (RIT) is a potential alternative treatment for NHL that is currently used in different lines of treatment. Studies show that nuclear medicine physicians and radiation oncologists are not yet certain about the proper line for administration of RIT. Herein, we have reviewed the efficiency and toxicity of RIT as the first line of treatment, and discussed potential novel indications, and strategies such as modifying induction therapy and using rituximab maintenance to optimize the efficiency of RIT as the first line of treatment. Our review indicates that it is more logical to postpone conventional therapies to the second or third lines of treatment instead of RIT.

Yttrium-90-Ibritumomab Tiuxetan (Zevalin®) Radioimmunotherapy after Cytoreduction with ESHAP Chemotherapy in Patients with Relapsed Follicular Non-Hodgkin Lymphoma: Final Results of a Phase II Study

BACKGROUND

Radioimmunotherapy (RIT) is effective in treating relapsed/refractory follicular lymphoma (FL), with durable remissions in first-line consolidation. We hypothesized that RIT with ibritumomab tiuxetan (Zevalin®) would result in durable remissions by eliminating minimal residual disease after cytoreduction.

METHODS

Patients with FL received 2 cycles of ESHAP (etoposide, methylprednisolone, cytarabine, cisplatin) every 28 days, followed by Zevalin 4-6 weeks later if there was no disease progression and bone marrow biopsy showed < 25% involvement.

RESULTS

Twenty-eight patients were treated, with a median age of 61 years, median of 3 prior therapies, 49% high-risk disease (Follicular Lymphoma International Prognostic Index, FLIPI), and 39% progressive disease. Three patients did not receive Zevalin due to residual bone marrow involvement. The main toxicities were cytopenias, with 11% febrile neutropenia. The overall response rate (ORR) was 72%, with 45% achieving complete response. With a median follow-up of 73 months, 1-year progression-free survival (PFS) was 38%, and median PFS was 10 months, but median overall survival (OS) was not reached.

CONCLUSION

The study did not reach its primary endpoint of a 1-year PFS of 67.3%. Reasons for this could include low accrual, high-risk disease, and inadequate debulking provided by 2 cycles of ESHAP. However, this protocol was associated with tolerable toxicity, high ORR, and high OS. Further studies would optimize debulking and focus on high-risk FL patients.

Risk of histological transformation and therapy-related myelodysplasia/acute myeloid leukaemia in patients receiving radioimmunotherapy for follicular lymphoma

Histological transformation (HT) of follicular lymphoma (FL) to an aggressive lymphoma after chemotherapy remains a key issue. The incidence of HT after radioimmunotherapy (RIT) is unknown. This single institution study analysed the risk of HT in FL after treatment with yttrium-90 ibritumomab tiuxetan in 115 consecutive patients treated during 1987-2012. RIT was administered for progressive FL in 111 (97%) patients and as first-line therapy in the remaining 4. 28% (n = 32) had HT, occurring at a median of 60 months from diagnosis and 20 months after RIT. 48% (12/25) of patients who received fludarabine developed HT. The estimated 10-year risk of HT in the fludarabine and non-fludarabine groups was 67% and 26% respectively (P = 0·015). Only prior fludarabine was significantly associated with predicting the risk of HT after RIT. 8% (9/115) of patients developed therapy-related myelodysplastic syndrome/acute myeloid leukaemia (tMDS/AML) at a median of 41·4 months (range, 5-89). The estimated 10-year risk of tMDS/AML in non-fludarabine treated patients (n = 90) versus fludarabine treated (n = 25) was 13% and 29%, respectively. The estimated overall risk of FL undergoing HT at 10 years without fludarabine exposure appears similar to patients reported in the literature that have not received RIT. Patients with prior purine-analogue therapy are at significantly higher risk of HT.

Long-term outcomes, secondary malignancies and stem cell collection following bendamustine in patients with previously treated non-Hodgkin lymphoma

Despite the long history of bendamustine as treatment for indolent non-Hodgkin lymphoma, long-term efficacy and toxicity data are minimal. We reviewed long-term data from three clinical trials to characterize the toxicity and efficacy of patients receiving bendamustine. Data were available for 149 subjects at 21 sites. The median age was 60 years at the start of bendamustine (range 39-84), and patients had received a median of 3 prior therapies. The histologies included grades 1-2 follicular lymphoma (FL; n = 73), grade 3 FL (n = 23), small lymphocytic lymphoma (n = 20), marginal zone lymphoma (n = 15), mantle cell lymphoma (n = 9), transformed lymphomas (n = 5), lymphoplasmacytic lymphoma (n = 2) and not reported (n = 2). The median event-free survival was 14·1 months. Nine of 12 attempted stem cell collections were successful. With a median follow-up of 8·9 years, 23 patients developed 25 cancers, including 8 patients with myelodysplastic syndrome/acute myeloid leukaemia. These data provide important information regarding the long-term toxicity of bendamustine in previously treated patients. A small but meaningful number of patients achieved durable remissions following bendamustine. These rigorously collected, patient-level, long-term follow-up data provide reassurance that bendamustine or bendamustine plus rituximab is associated with efficacy and safety for patients with relapsed or refractory indolent non-Hodgkin lymphoma.

90-yttrium-ibritumomab tiuxetan consolidation of fludarabine, mitoxantrone, rituximab in intermediate/high-risk follicular lymphoma: updated long-term results after a median follow-up of 7 years

Radioimmunotherapy (RIT) after an induction phase with conventional chemoimmunotherapy became an attractive strategy of consolidation for patients with advanced follicular lymphoma: in particular, in many studies RIT was represented by yttrium-90-ibritumomab tiuxetan ((90) Y-IT). Independently by the different front-line treatment, updates on the long-term follow-up of these studies are needed because the disease course of follicular lymphoma is characterised by multiple relapses and progressively shorter durations of response. We report updated long-term efficacy and toxicity results of a multicenter phase II study on sequential treatment with four cycles of fludarabine, mitoxantrone, and rituximab followed by (90) Y-IT as front-line therapy for untreated patients with intermediate/high-risk follicular lymphoma. With a median follow-up of 84 months, only 19/49 (38.8%) complete response patients relapsed, yielding an estimated long-term disease-free survival of 62.6%. The 7-year overall survival was 72.7%. Four (7.3%) second acute myeloid leukemia occurred, with a median time following RIT of 42 months. A relevant patients' responsiveness to subsequent therapies occurred: approximately 65% of relapsed patients obtained a good clinical response after the second-line treatment. These data represented the first evidence of a real role even in the long period of 90Y-IT after a fludarabine-containing regimen plus rituximab in the treatment of high-risk follicular lymphoma.

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.