A Systematic Review of Clinical Applications of Anti-CD20 Radioimmunotherapy for Lymphoma.

PURPOSE: The clinical efficacy of anti-CD20 radioimmunotherapy (RIT) is due to a combination of extracellular mechanisms involving immune-mediated cytotoxicity, and intracellular mechanisms related to inhibition of CD20 signaling and DNA damage from ionizing radiation. In 2002, the first RIT was approved by the U.S. Food and Drug Administration for the treatment of patients with indolent B-cell follicular non-Hodgkin lymphoma (NHL). The 2 approved agents, 90 Y-ibritumomab tiuxetan (90Y-IT, Zevalin, Acrotech Biopharma) and 131 I-tositumomab (131-IT, Bexxar, GlaxoSmithKline) both target CD20. The aim of this study was to review the clinical applications and supporting clinical trial data of anti-CD20 RIT for lymphoma. METHODS: A review of published articles and abstracts on the clinical efficacy and safety of 90Y-IT and iodine I 131 tositumomab was performed. RESULTS: The clinical efficacy and safety of anti-CD20 RIT have been demonstrated in numerous clinical trials and case series. Agents have produced significant responses in patients with follicular NHLs and in off-label applications. Importantly, RIT has demonstrated promising findings in high-risk lymphomas and heavily pretreated and refractory patient populations. Associated toxicity profiles are noted as tolerable, acceptable, and most often reversible. CONCLUSIONS: In the 2 decades since its approval, anti-CD20 RIT continues to demonstrate efficacy, particularly with a proportion of patients maintaining long-term remissions. The combination of prolonged efficacy, tolerability, and treatment convenience makes RIT a reasonable alternative to other systemic therapies. It is recommended that further research on RIT should focus on biomarkers of long-term response, pretargeting, and sequencing of RIT in the treatment course.

Optimizing assessment of CD30 expression in Hodgkin lymphoma by controlling for low expression.

Since the approval of brentuximab vedotin (BV), assessment of CD30 status by immunohistochemistry gained increasing importance in the clinical management of patients diagnosed with CD30-expressing lymphomas, including classical Hodgkin lymphoma (CHL). Paradoxically, patients with low or no CD30 expression respond to BV. This discrepancy may be due to lack of standardization in CD30 staining methods. In this study, we examined 29 cases of CHL and 4 cases of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) for CD30 expression using a staining protocol that was designed to detect low CD30 expression levels, and an evaluation system similar to the Allred scoring system used for breast cancer evaluation. For CHL, 10% of cases had low scores and 3% were CD30 negative, with 3 cases in which the majority of tumor cells showed very weak staining. Unexpectedly, one of four cases of NLPHL was positive. We demonstrate intra-patient heterogeneity in CD30 expression levels and staining patterns in tumor cells. Three CHL cases with weak staining may have been missed without the use of control tissue for low expression. Thus, standardization of CD30 immunohistochemical staining with use of known low-expressing controls may aid in proper CD30 assessment and subsequent therapeutic stratification of patients.

Cost-Effectiveness and Economic Burden Analyses on All First-Line Treatments of Chronic Lymphocytic Leukemia.

OBJECTIVES: Several chemoimmunotherapy and targeted treatment regimens are approved as front-line therapies in chronic lymphocytic leukemia. We estimated for the 10-year cost-effectiveness of these treatment regimens and the economic burden of following the estimated risk-stratified 21 040 patients with chronic lymphocytic leukemia diagnosed in 2020 for 10 years. METHODS: A Markov model with 7 exclusive health states was specified over a 10-year time horizon. Treatment effectiveness inputs were obtained from a novel network meta-analysis on the progression-free survival, overall survival curves, and time to next treatment. Costs and utilities inputs were included for each health state for each treatment and discounted at 3.0%/year. Life-years (LYs) and quality-adjusted LYs (QALYs) for each treatment were determined. Using the lowest cost regimen as reference, the incremental cost-effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR) were estimated. The 10-year per-patient cost was determined by risk status and by initial treatment. RESULTS: Venetoclax-plus-obinutuzumab was the lowest cost regimen, hence the reference. Superior in effectiveness to all chemoimmunotherapies, it was cost saving. With the highest effectiveness gains at 6.26 LYs and 5.01 QALYs and despite being the most expensive regimen ($1 298 638 per patient), acalabrutinib-plus-obinutuzumab yielded the best ICER ($409 343/LY gained) and ICUR ($501 236/QALY gained). The remaining ICERs of targeted therapies ranged from $512 101/LY gained to $793 236/LY gained and the ICURs from $579 737/QALY gained to $869 300/QALY gained. The 10-year postdiagnosis low/high (venetoclax-plus-obinutuzumab/acalabrutinib-plus-obinutuzumab) economic burden ranges were $42 690 to $98 665 for low-risk, $141 339 to $326 660 for intermediate-risk, and $273 650 to $632 453 for high-risk patients. CONCLUSIONS: Compared with venetoclax-plus-obinutuzumab, chemoimmunotherapies are associated with less health benefits at higher cost. The targeted therapies achieve greater benefits at higher cost.

Cost-effectiveness and value of information analyses of Bruton's tyrosine kinase inhibitors in the treatment of relapsed or refractory mantle cell lymphoma in the United States.

BACKGROUND: Ibrutinib, acalabrutinib, and zanubrutinib have shown improvements in efficacy and safety over conventional chemoimmunotherapy in refractory or relapsed mantle cell lymphoma (R/R MCL). OBJECTIVE: To evaluate the comparative cost-effectiveness of the Bruton's tyrosine kinase inhibitors (BTKIs) and estimate the expected value of (partial) perfect information (EV[P]PI) in terms of net health benefits (NHBs) and net monetary benefits (NMBs) forgone. METHODS: Using a two-state Markov model (progression-free; progression or death), we estimated in base-case and probabilistic sensitivity analyses (PSAs) the incremental cost-effectiveness (ICER) and cost-utility ratios (ICUR) of, respectively, progression-free survival (PFS) life-years (PFLYs) and PFS quality-adjusted LY (PFQALY) gained (g) against 3-year and 5-year time horizons. A willingness-to-pay threshold of $150,000/PFQALY was used to assess the probability of being cost-effective in the PSA. EVPI was calculated from the respective NHBs and NMBs. RESULTS: Compared with ibrutinib, acalabrutinib yielded a 3-year ICER of $90,571 (PSA = $88,588)/PFLYg and ICUR of $117,098 ($110,063)/PFQALYg, whereas zanubrutinib yielded a 3-year ICER of $58,422 ($58,907)/PFLYg and ICUR of $73,027 ($73,634)/PFQALYg. The corresponding 5-year estimates were ICER of $73,918 ($74,189)/PFLYg and ICUR of $90,512 ($90,844)/PFQALYg for acalabrutinib and ICER of $48,641 ($48,732)/PFLYg and ICUR of $61,612 ($63,727)/PFQALYg for zanubrutinib. Compared with zanubrutinib, treatment with acalabrutinib yielded a 3-year ICER of $144,633 ($134,964)/PFLYg and ICUR of $197,227 ($166,109)/PFQALYg; the corresponding 5-year estimates were $117,579 ($118,161)/PFLYg and $136,144 ($136,818)/PFQALYg. The EVPI/patient was an NHB of 0.036 PFQALYs and NMB of $3,602 forgone, resulting in a population EVPI of $134,766,957 forgone. The EVPPIs/patient for effectiveness were NHB of 0.015 PFQALYs and NMB of $1,479, with corresponding values of 0.032 and $3,187 for costs and 0.015 and $1,519 for health-related quality of life forgone. CONCLUSIONS: This early cost-effectiveness analysis based on phase I/II clinical trials of BTKIs in R/R MCL suggests an additional PFS benefit for second-generation BTKIs compared with ibrutinib. However, the relative uncertainty due to the lack of direct trial evidence may lead to an opportunity cost or lost health benefits if the current evidence is adopted to compare between these products. Additional evidence is needed to address the relative efficacy of the BTKIs. DISCLOSURES: A. McBride serves on speakers bureaus for Coherus BioSciences and Merck. He is now at Bristol-Myers Squibb in a position unrelated to this study. I. Abraham is joint equity owner in Matrix45. By company policy, owners and employees are prohibited from owning equity in client and sponsor organizations (except through mutual funds or other independently administered collective investment instruments), contracting independently with client and sponsor organizations, or receiving compensation independently from such organizations. Matrix45 provides similar services to biopharmaceutical, diagnostics, and medical device companies on a nonexclusivity basis. Of relevance to this article, Matrix45 has not provided any services to this study. I. Abraham is the quantitative methods editor of JAMA Dermatology and deputy editor-in-chief of the Journal of Medical Economics. The remaining authors have no relevant financial or nonfinancial interests to disclose.

Transitioning ifosfamide chemotherapy regimens to the ambulatory setting: reviewing cost savings and safety profile.

PURPOSE: To characterize and compare both the outcome and cost of treatment of outpatient (OP) and inpatient (IP) ifosfamide therapy. METHODS: A single-center retrospective chart review of patients 18 years and older receiving ifosfamide therapy. The primary endpoint compares and evaluates the side effect profiles of ifosfamide-treated patients in the OP/IP settings. The adverse event grading system was characterized using the CTCAE Version 5.0. The highest grade was documented per cycle. The secondary endpoint of this study compares the costs of OP/IP therapy. It was assumed that the cost of medication was equivalent for IP/OP treatments. The cost saved with OP administration was determined by the average cost of hospital stay for IP admission. RESULTS: Ifosfamide therapy of 86 patients (57 OP, 29 IP) was reviewed. The predominant OP regimens were doxorobucin-ifosfamide-mesna (AIM) with 43.9% and ifosfamide-etoposide (IE) with 29.8%. Grade 4 anemia, thrombocytopenia, and neutropenia were most frequent in IP vs OP therapies (22.9% IP vs 4.3% OP, 21.6% IP vs 9.2% OP, and 22.8% IP vs 19.6% OP respectively). Neutropenic fever (NF) occurred in 20 OP patients which were predominantly treated with AIM or IE and led to average hospital stay of 6 days. Neurotoxicity, treated with methylene blue (MB) occurred in 4 OP patients. OP therapy saved a total of 783 hospital days, leading to a cost savings of $2,103,921. CONCLUSIONS: Transitioning ifosfamide to the OP setting is feasible for academic and community infusion centers with the OP administration being safe, well-tolerated, and associated with decreased total cost of care. The current processes allow for safe transition of chemotherapy of chemotherapy under times of COVID.

Safety and Efficacy of Engineered Toxin Body MT-3724 in Relapsed or Refractory B-cell Non-Hodgkin's Lymphomas and Diffuse Large B-cell Lymphoma.

MT-3724, a novel engineered toxin body comprised of an anti-CD20 single-chain variable fragment genetically fused to Shiga-like Toxin A subunit, is capable of binding to and internalizing against CD20, inducing cell killing via permanent ribosomal inactivation. This study evaluated MT-3724 in patients with relapsed/refractory B-cell non-Hodgkin lymphoma (r/rNHL). This open-label, multiple-dose phase Ia/b trial included a dose escalation in patients with r/rNHL according to a standard 3+3 design. Primary objectives were to determine the MTD and pharmacokinetics/pharmacodynamics. In a dose expansion study at MTD in serum rituximab-negative patients with diffuse large B-cell lymphoma (DLBCL), primary objectives were safety, tolerability, and pharmacokinetics/pharmacodynamics. Twenty-seven patients enrolled. MTD was 50 µg/kg/dose with 6,000 µg/dose cap. Thirteen patients experienced at least one grade ≥3 treatment-related adverse events; the most common grade ≥3 event was myalgia (11.1%). Two patients (75 µg/kg/dose) experienced grade 2 treatment-related capillary leak syndrome. Overall objective response rate was 21.7%. In serum rituximab-negative patients with DLBCL or composite DLBCL (n = 12), overall response rate was 41.7% (complete response, n = 2; partial response, n = 3). In patients with detectable baseline peripheral B cells, treatment resulted in dose-dependent B-cell depletion. The proportion of patients with anti-drug antibodies (ADA) increased during treatment and the majority appeared to be neutralizing based on an in vitro assay; nevertheless, tumor regression and responses were observed. MT-3724 demonstrated efficacy at the MTD in this population of previously treated patients with r/rDLBCL, with mild-to-moderate immunogenic safety events. Significance: This work describes the safety and efficacy of a new pharmaceutical pathway that could provide a treatment option for a subset of patients with a critical unmet therapeutic need. The study drug, MT-3724, is capable of targeting B-cell lymphomas via a unique, potent cell-killing mechanism that appears to be promising.

Targeting JAK/STAT Signaling Antagonizes Resistance to Oncolytic Reovirus Therapy Driven by Prior Infection with HTLV-1 in Models of T-Cell Lymphoma.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that infects at least 10 million people worldwide and is associated with the development of T-cell lymphoma (TCL). The treatment of TCL remains challenging and new treatment options are urgently needed. With the goal of developing a novel therapeutic approach for TCL, we investigated the activity of the clinical formulation of oncolytic reovirus (Reolysin, Pelareorep) in TCL models. Our studies revealed that HTLV-1-negative TCL cells were highly sensitive to Reolysin-induced cell death, but HTLV-1-positive TCL cells were resistant. Consistent with these data, reovirus displayed significant viral accumulation in HTLV-1-negative cells, but failed to efficiently replicate in HTLV-1-positive cells. Transcriptome analyses of HTLV-1-positive vs. negative cells revealed a significant increase in genes associated with retroviral infection including interleukin-13 and signal transducer and activator of transcription 5 (STAT5). To investigate the relationship between HTLV-1 status and sensitivity to Reolysin, we infected HTLV-1-negative cells with HTLV-1. The presence of HTLV-1 resulted in significantly decreased sensitivity to Reolysin. Treatment with the JAK inhibitor ruxolitinib suppressed STAT5 phosphorylation and expression of the key anti-viral response protein MX1 and enhanced the anti-TCL activity of Reolysin in both HTLV-1-positive and negative cells. Our data demonstrate that the inhibition of the JAK/STAT pathway can be used as a novel approach to antagonize the resistance of HTLV-1-positive cells to oncolytic virus therapy.

Same-day versus next-day pegfilgrastim or pegfilgrastim-cbqv in patients with lymphoma receiving CHOP-like chemotherapy.

Aim: To compare the incidence of febrile neutropenia and related outcomes of prophylactic same-day versus next-day pegfilgrastim/pegfilgrastim-cbqv in patients with lymphoma receiving cyclophosphamide, hydroxydaunorubicin, vincristine, prednisone (CHOP)-like chemotherapy. Methods: Retrospective, real-world, single-institution study. Results: 93 patients received 460 cycles of CHOP-like chemotherapy. The incidence of febrile neutropenia and grade 3/4 chemotherapy-induced neutropenia was 5 and 16.5%, respectively. In 401 cycles pegfilgrastim was administered same-day versus 12 cycles next-day. Febrile neutropenia occurred in 17 cycles versus 0 cycles (p = 1.00) and grade 3/4 chemotherapy-induced neutropenia in 65 cycles (16.2%) versus 1 cycle (16.7%; p = 1.00) with same-day versus next-day pegfilgrastim administration, respectively. Conclusion: Pegfilgrastim may be safely administered on the same day as chemotherapy in patients with lymphoma receiving CHOP-like chemotherapy.

Lay abstract Aside from killing cancer cells, chemotherapy can also affect the growth of immune cells that normally prevent infections. Without enough of these immune cells in the blood, the patient's body cannot fight infections. This can lead to a serious condition called febrile neutropenia, and death in the most severe cases. Pegfilgrastim, a growth factor that helps important types of immune cells to grow, can prevent this side effect of chemotherapy. Usually, pegfilgrastim is administered the day after chemotherapy but there is a trend to administer it on the day of chemotherapy, but whether this is effective and safe is currently unclear. This study from the University of Arizona Cancer Center showed that administration of pegfilgrastim on the same day as chemotherapy is a safe, effective method of preventing febrile neutropenia in patients who receive standard-of-care chemotherapy to treat lymphoma.

Comparative Efficacy of First-Line Treatments of Chronic Lymphocytic Leukemia: Network Meta-Analyses of Survival Curves.

BACKGROUND: Multiple treatment options in first-line chronic lymphocytic leukemia (CLL) pose a challenge in identifying the best treatment. We performed novel network meta-analyses (NMA; 8 trials, 11 treatments) on the Kaplan-Meier curves to compare treatments for fludarabine-ineligible patients on progression-free survival (PFS), time-to-next-treatment (TTNT) and overall survival (OS). METHODS: Using the Guyot method of enhanced secondary analysis of digitized survival data and applying the fixed lognormal distribution model, we extracted the survival proportions and hazard ratios (HR) over 60 months of follow-up, including PFS comparisons by unmutated/mutated IGHV and del 17p. RESULTS: Acalabrutinib-plus-obinutuzumab was associated with higher 5-year PFS proportions than ibrutinib (HR = 0.42, 95% CrI = 0.25-0.63) but not acalabrutinib, ibrutinib-plus-obinutuzumab, ibrutinib-plus-rituximab or venetoclax-plus-obinutuzumab. In patients with un-mutated (but not with mutated) IGHV higher PFS proportions and favorable HRs were observed for acalabrutinib, acalabrutinib-plus-obinutuzumab, and ibrutinib-plus-obinutuzumab relative to ibrutinib; and targeted therapies were superior over chemoimmunotherapies in patients with del 17p. Targeted therapies containing ibrutinib or acalabrutinib regimens were associated with superior TTNT over venetoclax-plus-obinutuzumab and all chemoimmunotherapies. OS NMA generally found no difference between therapies except for some chemoimmunotherapies. CONCLUSIONS: Overall, only acalabrutinib-plus-obinutuzumab was associated with superior 5-year PFS gains over ibrutinib, which in turn was similar or superior in PFS benefit over other targeted therapies. Acalabrutinib and ibrutinib with obinutuzumab and acalabrutinib monotherapy were associated with greater 5-year TTNT benefits. Despite marked 5-year OS for many regimens, a differential 5-year OS benefit could not be ascertained.

Survival trends in chronic lymphocytic leukemia across treatment eras: US SEER database analysis (1985-2017).

In this population-based study, we used the SEER database (1985-2015) to examine survival outcomes in chronic lymphocytic leukemia (CLL) patients followed up to the era of advanced treatments including targeted therapies. Data were extracted for patients 15 years or older with a primary diagnosis of CLL. A period analysis was performed to estimate 5- and 10-year relative survival rates for patients diagnosed during different calendar periods from 1985 to 2015. A mixture cure model was used to examine long-term survivors' proportions among patients diagnosed in 1985-2015 and for two cohorts diagnosed in 2000-2003, followed up to 2012 and 2004-2007, and followed up to 2015. Cox proportional hazard modeling was used for the two cohorts to estimate hazard ratios (HRs) of death adjusted for gender and age. The 5-year and 10-year age-adjusted relative survival rate ranged between 73.7 and 89.4% and from 51.6% to "not reached," respectively, for calendar periods of 1985-1989 to 2010-2014. The long-term survivor proportions varied by age and gender from 0 to 59%. The HRs (95%CI) for the 2004-2007 cohort in comparison to the 2000-2003 cohort were 0.58 (0.43-0.78), 0.58 (0.48-0.70), 0.57 (0.49-0.0.67), 0.68 (0.54-0.85), and 0.83 (0.68-1.02) for the age categories of 45-54, 55-64, 65-74, 75-84, and ≥ 85 years, respectively. Overall, relative survival improved significantly for CLL patients diagnosed between 1985 and 2015. These improvements were markedly better following the introduction of targeted therapies.

The Chronic Lymphocytic Leukemia Comorbidity Index (CLL-CI): A Three-Factor Comorbidity Model.

PURPOSE: Comorbid medical conditions define a subset of patients with chronic lymphocytic leukemia (CLL) with poor outcomes. However, which comorbidities are most predictive remains understudied. EXPERIMENTAL DESIGN: We conducted a retrospective analysis from 10 academic centers to ascertain the relative importance of comorbidities assessed by the cumulative illness rating scale (CIRS). The influence of specific comorbidities on event-free survival (EFS) was assessed in this derivation dataset using random survival forests to construct a CLL-specific comorbidity index (CLL-CI). Cox models were then fit to this dataset and to a single-center, independent validation dataset. RESULTS: The derivation and validation sets comprised 570 patients (59% receiving Bruton tyrosine kinase inhibitor, BTKi) and 167 patients (50% receiving BTKi), respectively. Of the 14 CIRS organ systems, three had a strong and stable influence on EFS: any vascular, moderate/severe endocrine, moderate/severe upper gastrointestinal comorbidity. These were combined to create the CLL-CI score, which was categorized into 3 risk groups. In the derivation dataset, the median EFS values were 58, 33, and 20 months in the low, intermediate, and high-risk groups, correspondingly. Two-year overall survival (OS) rates were 96%, 91%, and 82%. In the validation dataset, median EFS values were 81, 40, and 23 months (two-year OS rates 97%/92%/88%), correspondingly. Adjusting for prognostic factors, CLL-CI was significantly associated with EFS in patients treated with either chemo-immunotherapy or with BTKi in each of our 2 datasets. CONCLUSIONS: The CLL-CI is a simplified, CLL-specific comorbidity index that can be easily applied in clinical practice and correlates with survival in CLL.

Outcomes of primary and secondary prophylaxis of chemotherapy-induced and febrile neutropenia in bendamustine plus rituximab regimens in patients with lymphoma and chronic lymphocytic leukemia: real-world, single-center experience.

PURPOSE: To examine the outcomes associated with granulocyte colony stimulating factors (G-CSFs) administered as primary versus secondary prophylaxis in setting of bendamustine plus rituximab (BR) regimens. METHODS: Eighty-five patients who underwent treatment for non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) with BR at the University of Arizona Cancer Center from November 2013 to June 2019 were evaluated through retrospective chart review. Patients were stratified into two groups: those who were given G-CSF for primary prophylaxis (n = 47) and for secondary prophylaxis (n = 38). G-CSF-included filgrastim or pegfilgrastim. The primary endpoints were incidence of febrile neutropenia and grade 3 or 4 neutropenia. RESULTS: Same-day G-CSF compared with next-day G-CSF was the most common G-CSF dosing method utilized in primary and secondary prophylaxis (94% and 100%), respectively. Primary and secondary prophylaxis groups were similar on baseline characteristics (p > 0.05); the primary outcome of FN (p > 0.05); all secondary outcomes (p > 0.05) except for a higher frequency of dose delays in secondary (40%) vs primary prophylaxis patients (13%; p = 0.01), and mean absolute neutrophil counts (ANC) in cycles 1 through 5. With higher ANC levels observed during all cycles in the primary prophylaxis group compared with secondary prophylaxis. CONCLUSIONS: In this single-center retrospective study, BR-treated lymphoma and CLL patients receiving primary versus secondary with G-CSF showed similar outcomes except, notably, for chemotherapy dose delays that may put secondary patients at risk for poor treatment outcomes. Further research is needed to evaluate the impact of primary versus secondary prophylaxis on treatment outcomes.

Incorporating acalabrutinib, a selective next-generation Bruton tyrosine kinase inhibitor, into clinical practice for the treatment of haematological malignancies.

Greater understanding of the mechanisms involved in the disease progression of haematological malignancies has led to the introduction of novel targeted therapies with reduced toxicity compared with chemotherapy-based regimens, which has expanded the treatment options for patients with mantle cell lymphoma (MCL) and chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). Ibrutinib is a first-in-class Bruton tyrosine kinase (BTK) inhibitor indicated for the treatment of patients with CLL/SLL or relapsed/refractory MCL. However, next-generation BTK inhibitors have been developed with improved specificity and the potential to reduce the off-target toxicity observed with ibrutinib. Acalabrutinib is a highly selective, next-generation BTK inhibitor, which was granted accelerated approval by the US Food and Drug Administration in 2017 for the treatment of adult patients with MCL who have received at least one prior therapy. In November 2019, it was also granted approval for the treatment of adult patients with CLL/SLL on the basis of two phase 3 clinical trials. This review describes the current understanding of acalabrutinib according to clinical study data for the treatment of MCL and CLL/SLL and shares recommendations from our practice on how it should be used when treating patients in the clinic, including dosing, administration and management of adverse events.

Resistance to histone deacetylase inhibitors confers hypersensitivity to oncolytic reovirus therapy.

Despite the promising antilymphoma activity of histone deacetylase (HDAC) inhibitors as a drug class, resistance is a significant clinical issue. Elucidating the molecular mechanisms driving HDAC inhibitor resistance and/or the specific targets that are altered in drug-resistant cells may facilitate the development of strategies that overcome drug resistance and are more effective for refractory patients. We generated novel T-cell lymphoma (TCL) cell line models of acquired resistance to the HDAC inhibitor belinostat to identify potential effective therapies. Belinostat-resistant cells displayed significant cross-resistance to other HDAC inhibitors including romidepsin, panobinostat, and vorinostat. Consistent with a lack of sensitivity to HDAC inhibitors, the resistant cells failed to induce increased acetylated histones. Drug-resistant cells featured significantly decreased expression of the key antiviral mediators IRF1 and STAT1. On the basis of these findings, we investigated the efficacy of the clinical formulation of reovirus (Reolysin) in parental and drug-resistant models. Our investigation revealed that HDAC inhibitor-resistant cells displayed enhanced vulnerability to reovirus replication and cell death in both in vitro and in vivo models compared with their parental counterparts. Importantly, Reolysin also significantly increased the antilymphoma activity of belinostat in HDAC inhibitor-resistant cells. Our data demonstrate that Reolysin alone or in combination with belinostat is a novel therapeutic strategy to treat TCL patients who develop resistance to HDAC inhibitors.

Checkpoint Blockade Treatment May Sensitize Hodgkin Lymphoma to Subsequent Therapy.

BACKGROUND: Targeted therapies and checkpoint blockade therapy (CBT) have shown efficacy for patients with Hodgkin lymphoma (HL) in the relapsed and refractory (R/R) setting, but once discontinued owing to progression or side effects, it is unclear how successful further therapies will be. Moreover, there are no data on optimal sequencing of these treatments with standard therapies and other novel agents. In a multicenter, retrospective analysis, we investigated whether exposure to CBT could sensitize HL to subsequent therapy. MATERIALS AND METHODS: Seventeen centers across the U.S. and Canada retrospectively queried medical records for eligible patients. The primary aim was to evaluate the overall response rate (ORR) to post-CBT treatment using the Lugano criteria. Secondary aims included progression-free survival (PFS), duration of response, and overall survival (OS). RESULTS: Eighty-one patients were included. Seventy-two percent had stage III-IV disease, and the population was heavily pretreated with a median of four therapies before CBT. Most patients (65%) discontinued CBT owing to progression. The ORR to post-CBT therapy was 62%, with a median PFS of 6.3 months and median OS of 21 months. Post-CBT treatment regimens consisted of chemotherapy (44%), targeted agents (19%), immunotherapy (15%), transplant conditioning (14%), chemotherapy/targeted combination (7%), and clinical trials (1%). No significant difference in OS was found when stratified by post-CBT regimen. CONCLUSION: In a heavily pretreated R/R HL population, CBT may sensitize patients to subsequent treatment, even after progression on CBT. Post-CBT regimen category did not impact OS. This may be a novel treatment strategy, which warrants further investigation in prospective clinical trials. IMPLICATIONS FOR PRACTICE: Novel, life-prolonging treatment strategies in relapsed and refractory (R/R) Hodgkin lymphoma (HL) are greatly desired. The results of this multicenter analysis concur with a smaller, earlier report that checkpoint blockade therapy (CBT) use in R/R HL may sensitize patients to their subsequent treatment. This approach may potentially enhance therapeutic options or to bridge patients to transplant. Prospective data are warranted prior to practice implementation. As more work is done in this area, we may also be able to optimize sequencing of CBT and novel agents in the treatment paradigm to minimize treatment-related toxicity and thus improve patient quality of life.

Positron Emission Tomography-Directed Therapy for Patients With Limited-Stage Diffuse Large B-Cell Lymphoma: Results of Intergroup National Clinical Trials Network Study S1001.

PURPOSE: Diffuse large B-cell lymphoma (DLBCL) presents as a limited-stage disease in 25% to 30% of patients, with better overall survival (OS) than that for advanced-stage disease but with continuous relapse regardless of treatment approach. The preferred treatment is abbreviated rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and radiation therapy. On the basis of promising results of positron emission tomography (PET)-directed treatment approaches, we designed a National Clinical Trials Network (NCTN) study to improve outcomes and decrease toxicity. METHODS: Patients with nonbulky (< 10 cm) stage I/II untreated DLBCL received 3 cycles of standard R-CHOP therapy and underwent a centrally reviewed interim PET/computed tomography scan (iPET). Those with a negative iPET proceeded with 1 additional cycle of R-CHOP, whereas those with a positive iPET received involved field radiation therapy followed by ibritumomab tiuxetan radioimmunotherapy. RESULTS: Of 158 patients enrolled, 132 were eligible and 128 underwent iPET, which was positive in 14 (11%) of the patients. With a median follow-up of 4.92 years (range, 1.1-7.7 years), only 6 patients progressed and 3 died as a result of lymphoma. Eleven patients died as a result of nonlymphoma causes at a median age of 80 years. The 5-year progression-free survival estimate was 87% (95% CI, 79% to 92%) and the OS estimate was 89% (95% CI, 82% to 94%), with iPET-positive and iPET-negative patients having similar outcomes. CONCLUSION: To our knowledge, S1001 is the largest prospective study in the United States of limited-stage DLBCL in the rituximab era, with the best NCTN results in this disease subset. With PET-directed therapy, 89% of the patients with a negative iPET received R-CHOP × 4, and only 11% had a positive iPET and required radiation, with both groups having excellent outcomes. The trial establishes R-CHOP × 4 alone as the new standard approach to limited-stage disease for the absolute majority of patients.