Early treatment intensification with R-ICE and 90Y-ibritumomab tiuxetan (Zevalin)-BEAM stem cell transplantation in patients with high-risk diffuse large B-cell lymphoma patients and positive interim PET after 4 cycles of R-CHOP-14

Radioligand Therapy in Lymphoma: Past, Present, and Future

In the1980s, radiolabeled cells helped understand the pathology of hemato-oncology. In the 1990s, preclinical trials evaluated radiolabeled immunotherapy with monoclonal antibodies (MoAbs) such as anti-CD20 agents labeled with Iodine-131 (Bexxar) or Yttrium-90 (Zevalin). Due to the safe and durable responses of radiolabeled MoAbs, the Food and Drug Administration approved these agents in the 2000s. Despite radioimmunotherapy's long journey, its application has recently decreased. This review will discuss the historical timeline of radioimmunotherapy, debate on advantages and difficulties, and explore trials. We will examine future directions of radioligand therapy in hemato-oncology, considering emerging molecules that may become the next theragnostic trend.

Consolidative Autotransplantation Achieves High Cure Rates in Adverse-Risk Large B Cell Lymphoma

There remains an unmet need to optimize the first-line treatment of patients with high-risk large B cell lymphoma (LBCL), particularly those with a high International Prognostic Index (IPI) score or a positive interim positron emission tomography (PET) scan who experience poor outcomes with R-CHOP. This study was conducted to evaluate the real-world effectiveness of consolidative autologous stem cell transplantation (ASCT) among patients with high-risk LBCL. This retrospective study included consecutive patients with LBCL and IPI score 4 or 5 who underwent consolidative ASCT as part of first-line therapy in Alberta, Canada. Progression-free survival (PFS), overall survival (OS), and disease-specific survival (DSS) were determined using the Kaplan-Meier method. The study cohort comprised 114 patients with median age of 60 years (range, 18 to 73 years), of whom 81 (71%) had an IPI score of 4 and 33 (29%) had an IPI score of 5. With a median follow-up of 5.6 years, the 5-year PFS was 72% (95% confidence interval [CI], 62% to 79%), 5-year OS was 74% (95% CI, 64% to 81%), and 5-year DSS was 80% (95% CI, 71% to 87%). There was no significant difference in PFS among patients with and patients without positive interim PET scans (n = 24), MYC and BCL2 and/or BCL6 rearrangements (n = 26), or central nervous system involvement (n = 15). Consolidative ASCT is associated with high cure rates and favorable survival outcomes in patients with high-risk LBCL and may overcome the adverse prognostic impact of a positive interim PET scan.

Application of interim PET-CT in first-line treatment decision-making for lymphoma

Recent advances in lymphoma treatment have significantly improved the survival of patients; however, the current approaches also have varying side effects. To overcome these, it is critical to implement individualized treatment according to the patient's condition. Therefore, the early identification of high-risk groups and targeted treatment are important strategies for prolonging the survival time and improving the quality of life of patients. Interim positron emission tomography-computed tomography (PET-CT) has a high prognostic value, which can reflect chemosensitivity and identify patients for whom treatment may fail under this regimen. To date, many prospective clinical studies on interim PET (iPET)‍-adapted therapy have been conducted. In this review, we focus on the treatment strategies entailed in these studies, as well as the means and timing of iPET assessment, with the aim of exploring the efficacy and existing issues regarding iPET-adapted treatment. It is expected that the improved use of PET-CT examination can facilitate treatment decision-making to identify precise treatment options.

PET/CT in Non-Hodgkin Lymphoma: An Update

Non-Hodgkin lymphomas represents a heterogeneous group of lymphoproliferative disorders characterized by different clinical courses, varying from indolent to highly aggressive. ¹⁸F-FDG-PET/CT is the current state-of-the-art diagnostic imaging, for the staging, restaging and evaluation of response to treatment in lymphomas with avidity for ¹⁸F-FDG, despite it is not routinely recommended for surveillance. PET-based response criteria (using five-point Deauville Score) are nowadays uniformly applied in FDG-avid lymphomas. In this review, a comprehensive overview of the role of ¹⁸F-FDG-PET in Non-Hodgkin lymphomas is provided, at each relevant point of patient management, particularly focusing on recent advances on diffuse large B-cell lymphoma and follicular lymphoma, with brief updates also on other histotypes (such as marginal zone, mantle cell, primary mediastinal- B cell lymphoma and T cell lymphoma). PET-derived semiquantitative factors useful for patient stratification and prognostication and emerging radiomics research are also presented.

Are dynamic or fixed FDG-PET measures of disease of greater prognostic value in patients with relapsed/refractory diffuse large B-cell lymphoma undergoing autologous haematopoietic stem cell transplantation?

Positron emission tomography (PET) response assessment using the Deauville score has prognostic utility in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) undergoing autologous stem-cell transplantation (ASCT). Improved predictive methods are required to identify patients with poor outcomes who may be better considered for other salvage options. We investigated the prognostic value of mean tumour volume (MTV) and maximum standardised uptake value (SUVmax) at pre-salvage and pre-ASCT time-points, and the quantitative changes between scans (∆MTV and ∆SUVmax). One hundred and twenty-five patients with R/R DLBCL underwent salvage immunochemotherapy and ASCT: 80 patients had pre-salvage PET and 90 had pre-ASCT PET available. With a median follow-up of 5.6 years, 5-year progression-free survival (PFS) and overall survival (OS) were 52% and 65%, respectively. For patients with PET-positive residual disease after salvage therapy, pre-ASCT MTV was a significant negative prognosticator for PFS (HR 1.19 per 100 ml, p < 0.001) and OS (HR 1.78 per 100 ml, p < 0.001). Similarly, pre-ASCT SUVmax was negatively associated with PFS (HR 1.08, p < 0.001) and OS (HR 1.08, p < 0.001). Notably, pre-salvage MTV and SUVmax and ∆MTV and ∆SUVmax were not associated with PFS or OS. In conclusion, pre-ASCT MTV and SUVmax appear to be of greater predictive value than the degree of response. Potential application may exist for PET-directed management of R/R DLBCL patients.

Circulating tumor DNA in B-cell lymphoma: technical advances, clinical applications, and perspectives for translational research

Noninvasive disease monitoring and risk stratification by circulating tumor DNA (ctDNA) profiling has become a potential novel strategy for patient management in B-cell lymphoma. Emerging innovative therapeutic options and an unprecedented growth in our understanding of biological and molecular factors underlying lymphoma heterogeneity have fundamentally increased the need for precision-based tools facilitating personalized and accurate disease profiling and quantification. By capturing the entire mutational landscape of tumors, ctDNA assessment has some decisive advantages over conventional tissue biopsies, which usually target only one single tumor site. Due to its non- or minimal-invasive nature, serial and repeated ctDNA profiling provides a real-time picture of the genetic composition and facilitates quantification of tumor burden any time during the course of the disease. In this review, we present a comprehensive overview of technologies used for ctDNA detection and genotyping in B-cell lymphoma, focusing on pre-analytical and technical requirements, the advantages and limitations of various approaches, and highlight recent advances around improving sensitivity and suppressing technical errors. We broadly review potential applications of ctDNA in clinical practice and for translational research by describing how ctDNA might enhance lymphoma subtype classification, treatment response assessment, outcome prediction, and monitoring of measurable residual disease. We finally discuss how ctDNA could be implemented in prospective clinical trials as a novel surrogate endpoint and be utilized as a decision-making tool to guide lymphoma treatment in the future.

PET2 response associated with survival in newly diagnosed diffuse large B-cell lymphoma: results of two independent prospective cohorts

Studies evaluating Positron Emission Tomography scan after 2 cycles of chemotherapy (PET2) in newly diagnosed diffuse large B cell lymphoma (DLBCL) are heterogeneous in patient characteristics, treatments and have conflicting results. Here we report association of PET2 with outcomes in two large independent prospective cohorts of newly diagnosed DLBCL pts treated with two RCHOP-based regimens. The discovery cohort consisted of pts enrolled in single arm phase 2 MC078E study of lenalidomide with RCHOP (R2CHOP). The validation cohort consisted of RCHOP-treated pts from the Molecular Epidemiology Resource (MER) cohort. Pts who received 3-6 cycles of therapy and had PET2 were included in the study. Patients who progressed on PET2 were excluded. Revised response criteria 2007 were used to define PET2 response PET2 positive (PET2 + ) pts had inferior EFS [24-month EFS 45.5% vs 87.9%, HR 4.0, CI₉₅ (2.1-7.9), p < 0.0001) with a trend towards lower OS [24-months OS 77% vs 94.8%, HR 2.0, CI₉₅ (0.9-4.8), P = 0.1] than PET2 negative (PET2-) pts in MC078E cohort. PET2 + pts had an inferior EFS (24 month EFS 48.7% vs 81.6%, HR 2.9, CI₉₅ 2.0-4.2, p < 0.0001) and OS (24-month OS 68.6% vs 88.1%, HR 2.3, CI₉₅: 1.5-3.5, p < 0.0001) in the MER cohort. These results were consistent regardless of age, sex and in the subgroup of advanced stage and high-risk international prognostic index (IPI). For MER, PET2 + pts also had higher odds of positive end of treatment PET (OR: 17.3 (CI₉₅ 7.9-37.7), p < 0.001). PET2 is an early predictor DLBCL pts at high risk of progression and death in two independent prospective cohorts. PET2-guided risk-adapted strategies may improve outcomes, and should be explored in clinical trials.

Positron Emission Tomography Molecular Imaging for Phenotyping and Management of Lymphoma

Positron emission tomography (PET) represents molecular imaging for non-invasive phenotyping of physiological and biochemical processes in various oncological diseases. PET imaging with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) for glucose metabolism evaluation is the standard imaging modality for the clinical management of lymphoma. One of the ¹⁸F-FDG PET applications is the detection and pre-treatment staging of lymphoma, which is highly sensitive. ¹⁸F-FDG PET is also applied during treatment to evaluate the individual chemo-sensitivity and accordingly guide the response-adapted therapy. At the end of the therapy regiment, a negative PET scan is indicative of a good prognosis in patients with advanced Hodgkin's lymphoma and diffuse large B-cell lymphoma. Thus, adjuvant radiotherapy may be alleviated. Future PET studies using non-¹⁸F-FDG radiotracers, such as ⁶⁸Ga-labeled pentixafor (a cyclic pentapeptide that enables sensitive and high-contrast imaging of C-X-C motif chemokine receptor 4), ⁶⁸Ga-labeled fibroblast activation protein inhibitor (FAPI) that reflects the tumor microenvironment, and ⁸⁹Zr-labeled atezolizumab that targets the programmed cell death-ligand 1 (PD-L1), may complement ¹⁸F-FDG and offer essential tools to decode lymphoma phenotypes further and identify the mechanisms of lymphoma therapy.

[Dose-enhanced immunochemotherapy followed by first-line autologous peripheral blood stem cell transplantation for young patients with high-risk aggressive B-cell lymphoma: an efficacy and prognostic factor analysis]

Objective: This study aimed to determine the efficacy of dose-enhanced immunochemotherapy followed by autologous peripheral blood stem cell transplantation (ASCT) in young patients with newly diagnosed high-risk aggressive B-cell lymphoma. Methods: A retrospective study was conducted to examine the clinical and survival data of young patients with high-risk aggressive B-cell lymphoma who received dose-enhanced immunochemotherapy and ASCT as first-line treatment between January 2011 and December 2018 in Blood Diseases Hospital. Results: A total of 63 patients were included in the study. The median age range was 40 (14-63) years old. In terms of the induction therapy regimen, 52 cases received R-DA-EP (D) OCH, and the remaining 11 received R-HyperCVAD/R-MA. Sixteen (25.4% ) patients achieved partial response in the mid-term efficacy assessment, and ten of them were evaluated as complete response after transplantation. The median follow-up was 50 (8-112) months, and the 3-year progression-free survival (PFS) rate and overall survival (OS) rate were (83.9±4.7) % and (90.4±3.7) % , respectively. Univariate analysis demonstrated that age-adjusted international prognostic index ≥2 scores was a negative prognostic factor for OS (P=0.039) , and bone marrow involvement (BMI) was an adverse prognostic factor for OS (P<0.001) and PFS (P=0.001) . However, multivariate analysis confirmed that BMI was the only independent negative predictor of OS (P=0.016) and PFS (P=0.001) . Conclusions: The use of dose-enhanced immunochemotherapy in combination with ASCT as first-line therapy in the treatment of young, high-risk aggressive B-cell lymphoma results in good long-term outcomes, and BMI remains an adverse prognostic factor.

Risk profiling of patients with relapsed/refractory diffuse large B-cell lymphoma by measuring circulating tumor DNA

The level of baseline ctDNA correlated with PFS and OS in patients with R/R DLBCL receiving pola plus BR or BR alone.

Patients with a CR had a significantly greater median decrease in ctDNA levels at end of treatment than patients without a CR.

Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) have heterogeneous outcomes; durable remissions are infrequently observed with standard approaches. Circulating tumor DNA (ctDNA) assessment is a sensitive, potentially prognostic tool in this setting. We assessed baseline ctDNA to identify patients with R/R DLBCL at high risk of relapse after receiving polatuzumab vedotin and bendamustine plus rituximab (BR) or BR alone. Patients were transplant ineligible and had received ≥1 prior line of therapy. The ctDNA assay, based on a customized panel of recurrently mutated genes in DLBCL, measured mutant molecules per mL (MMPM) at baseline and end of treatment (EOT). Endpoints included progression-free survival (PFS) and overall survival (OS) in subgroups stratified by baseline ctDNA and log-fold change in ctDNA at EOT vs baseline. In biomarker-evaluable patients (n = 33), baseline ctDNA level correlated with serum lactate dehydrogenase (LDH) concentration, number of prior therapies, stage, and International Prognostic Index (IPI). After adjusting for number of prior therapies ≥2, IPI score ≥3, and LDH above the upper limit of normal, high (greater than median) baseline ctDNA MMPM was independently prognostic for shorter PFS (adjusted hazard ratio [HR], 0.18 [95% CI, 0.05-0.65]) and OS (adjusted HR, 0.20 [95% CI, 0.06-0.68]). In 23 patients with baseline and EOT samples, a significantly greater decrease in ctDNA MMPM was observed in patients with complete response (CR) (n = 13) than those without CR (n = 10); P = .0025. Baseline ctDNA assessment may identify patients at high risk of progression and should be further evaluated as a monitoring tool in R/R DLBCL. This trial was registered at www.clinicaltrials.gov as #NCT02257567.

Anti-CD25 radioimmunotherapy with BEAM autologous hematopoietic cell transplantation conditioning in Hodgkin lymphoma

High-risk relapsed or refractory (R/R) classical Hodgkin lymphoma (HL) is associated with poor outcomes after conventional salvage therapy and autologous hematopoietic cell transplantation (AHCT). Post-AHCT consolidation with brentuximab vedotin (BV) improves progression-free survival (PFS), but with increasing use of BV early in the treatment course, the utility of consolidation is unclear. CD25 is often expressed on Reed-Sternberg cells and in the tumor microenvironment in HL, and we hypothesized that the addition of 90Y-antiCD25 (aTac) to carmustine, etoposide, cytarabine, melphalan (BEAM) AHCT would be safe and result in a transplantation platform that is agnostic to prior HL-directed therapy. Twenty-five patients with high-risk R/R HL were enrolled in this phase 1 dose-escalation trial of aTac-BEAM. Following an imaging dose of 111In-antiCD25, 2 patients had altered biodistribution, and a third developed an unrelated catheter-associated bacteremia; therefore, 22 patients ultimately received therapeutic 90Y-aTac-BEAM AHCT. No dose-limiting toxicities were observed, and 0.6 mCi/kg was deemed the recommended phase 2 dose, the dose at which the heart wall would not receive >2500 cGy. Toxicities and time to engraftment were similar to those observed with standard AHCT, though 95% of patients developed stomatitis (all grade 1-2 per Bearman toxicity scale). Seven relapses (32%) were observed, most commonly in patients with ≥3 risk factors. The estimated 5-year PFS and overall survival probabilities among 22 evaluable patients were 68% and 95%, respectively, and non-relapse mortality was 0%. aTac-BEAM AHCT was tolerable in patients with high-risk R/R HL, and we are further evaluating the efficacy of this approach in a phase 2 trial. This trial was registered at www.clinicaltrials.gov as #NCT01476839.

Intratumoral T-cell receptor repertoire is predictive of interim PET scan results in patients with diffuse large B-cell lymphoma treated with rituximab/cyclophosphamide/doxorubicin/prednisolone/vincristine (R-CHOP) chemoimmunotherapy

Objectives

A diverse intratumoral T‐cell receptor (TCR) repertoire is associated with improved survival in diffuse large B‐cell lymphoma (DLBCL) treated with rituximab/cyclophosphamide/doxorubicin/prednisolone/vincristine (R‐CHOP) chemoimmunotherapy. We explored the impact of intratumoral TCR repertoire on interim PET (iPET) done after four cycles of R‐CHOP, the relationships between intratumoral and circulating repertoire, and the phenotypes of expanded clonotypes.

Methods

We sequenced the third complementarity‐determining region of TCRβ in tumor samples, blood at pre‐therapy and after four cycles of R‐CHOP in 35 patients enrolled in ALLGNHL21 trial in high‐risk DLBCL. We correlated the TCR diversity metrics with iPET status, gene expression profiles and HLA‐class I genotypes. We then sequenced the FACS‐sorted peripheral blood T cells in six patients, and pentamer‐sorted EBV‐specific CD8⁺ T cells in one patient from this cohort.

Results

Compared with iPET⁻ patients, the intratumoral TCR repertoire in iPET⁺ patients was characterised by higher cumulative frequency of abundant clonotypes and higher productive clonality. There was a variable overlap between circulating and intratumoral repertoires, with the dominant intratumoral clonotypes more likely to be detected in the blood. The majority of shared clonotypes were CD8⁺ PD‐1^HI T cells, and CD8⁺ T cells had the largest clonal expansions in tumor and blood. In a patient with EBV⁺ DLBCL, EBV‐specific intratumoral clonotypes were trackable in the blood.

Conclusion

This study demonstrates that clonally expanded intratumoral TCR repertoires are associated with iPET⁺ and that the blood can be used to track tumor‐associated antigen‐specific clonotypes. These findings assist the rationale design and therapeutic monitoring of immunotherapeutic strategies in DLBCL.

PET-guided treatment for personalised therapy of Hodgkin lymphoma and aggressive non-Hodgkin lymphoma

FDG-PET scanning has a central role in lymphoma staging and response assessment. There is a growing body of evidence that PET response assessment during and after initial systemic therapy can provide useful prognostic information, and PET response has an evolving role in guiding patient care. This review provides a perspective on the role of PET response assessment for individualised management of patients with the most common aggressive lymphomas, Hodgkin lymphoma and diffuse large B-cell lymphoma.

The optimal use of PET/CT in the management of lymphoma patients

¹⁸F-fluoro-deoxyglucose positron emission tomography (PET)/computed tomography (CT) scans play an important role in the management of lymphoma patients. They are critical to accurately stage disease and assess its response to therapy. In addition, PET/CT scans enable precise target delineation for radiation therapy planning. In this review, we describe the use of PET/CT scans in lymphoma, with a focus on their role in staging disease, assessing response to therapy, predicting prognosis, and planning RT.

Diffuse large B-cell lymphoma: A consensus practice statement from the Australasian Lymphoma Alliance

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, accounting for 30-40% of lymphoma diagnoses. Though aggressive, cure is achievable in approximately 60% of cases with primary chemo-immunotherapy, and in a further substantial minority by salvage therapy and autologous stem cell transplantation. Despite promising activity in early phase clinical trials, no intensified or novel treatment regimen has improved outcomes over R-CHOP21 in randomised studies. However, there remain several areas of controversy including the most appropriate prognostic markers, CNS prophylaxis and the optimal treatment for patients with high-risk disease. This position statement presents an evidence-based synthesis of the literature for application in Australasian practice. This article is protected by copyright. All rights reserved.

Predicting primary treatment failure using interim FDG-PET scanning in diffuse large B-cell lymphoma

Interim FDG-PET (iPET) in diffuse large B-cell lymphoma (DLBCL) is increasingly practised and used in clinical trials to adapt further therapy. However, the optimum timing and methodology of iPET remains controversial. We retrospectively analysed the iPET results and outcomes of 200 DLBCL patients where FDG-PET was routinely performed at baseline, after 2 cycles (iPET2) and at completion of chemoimmunotherapy. iPET was also performed after 4 cycles (iPET4) where at iPET2, Deauville score (DS) was ≥4. Scans were assessed by blinded expert lymphoma PET physicians for DS, maximum standard uptake value (SUVmax), total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG). Treatment failure was defined as death, progression or refractory disease. 95.5% of patients received R-CHOP. No baseline PET parameter was predicted for EFS or OS independent of the NCCN-IPI. The multivariable analysis at iPET2 showed DS5 (19.5% of cases) predicted treatment failure (HR 6.29, 95% CI 3.01-13.17, P < .001), but DS4 was equivalent to DS1-3. At iPET4, ΔSUVmax < 66% predicted treatment failure (HR 5.49, 95% CI 3.03-9.99, P < .001). By multivariable analysis of all time points, high NCCN-IPI and DS5 at iPET2 were negative predictors of survival. These findings were independent of novel prognostic markers.

End-of-treatment 18F-FDG PET/CT in diffuse large B cell lymphoma patients: ΔSUV outperforms Deauville score

In DLBCL, the Deauville scoring system (DS) is the standard for PET/CT response assessment. An alternative system, based on the semi-quantitative change in standardized uptake values, namely ΔSUVmax, has been reported to be more objective than the DS. We aimed to compare ΔSUVmax and DS for risk stratification of DLBCL patients on end-of-treatment (EoT) PET. 108 consecutive patients were included. 2-year EFS Kaplan-Meier survival analyses and Cox regression models were performed. 2-year EFS was significantly different between favorable ΔSUVmax (favΔ < -86.5%) and unfavorable ΔSUVmax (unfavΔ ≥ -86.5%) patients: 100.0% ± 0.0 versus 58.3% ± 14.2 (p = 0.001). On Cox multivariable regression, ΔSUVmax status was the only independent predictor of 2-year EFS, outperforming DS. Therefore, ΔSUVmax should be computed for non-responder patients, especially DS4, as the 2-year EFS is not different between responders and non-responders in the case of favΔ. Further studies are needed in order to confirm this hypothesis.

Improved prediction of chemoresistance in patients with diffuse large B-cell lymphoma through a new interim positron emission tomography-computed tomography evaluation model

OBJECTIVES

The positron emission tomography (PET) could predict the prognosis of DLBCL patients, but the exact procedure on interim PET (iPET) to determine chemoresistant patients remains elusive.

METHODS

We retrospectively analyzed 593 newly diagnosed DLBCL patients uniformly treated with R-CHOP regimen. Among them, 352 patients diagnosed from August 2010 to December 2016 were included in the test cohort and 241 patients diagnosed from January 2017 to December 2019 were included in the validation cohort. The iPET was evaluated with Deauville criteria and ΔSUVmax method. The reduction of maximal SUV between baseline and after 4 cycles of chemotherapy were defined as ΔSUVmax. The survival functions were depicted using the Kaplan-Meier method and compared with the log-rank test.

RESULTS

Patients with iPET Deauville 4 had heterogeneous outcome and end of treatment complete response rates (eCRR). Combined Deauville with ΔSUVmax method, we proposed a modified-Deauville model: patients with Deauville 4 and ΔSUVmax > 70%, as well as those with Deauville 1-3, were reclassified into the modified-Deauville negative group, while patients with Deauville 4 and ΔSUVmax ≤ 70%, as well as those with Deauville 5, into the modified-Deauville positive group. In the test cohort, 3-year PFS, OS and eCRR of modified-Deauville negative group were 80.2%, 89.9% and 91.8%, significantly higher than those of positive group (12.5%, 27.3% and 29.2%, p ≤ .001). Similar results were found in the validation cohort, that 3-year PFS, OS and eCRR were 87.8%, 95.4%, 96.3% in modified-Deauville negative group, and 27.4%, 32.5%, 13.5% in positive group. Through modified-Deauville model, patients in iPET positive group had very low eCRR and were resistant to conventional chemotherapy.

CONCLUSIONS

The modified-Deauville model could better distinguish DLBCL patients with poor response to chemotherapy. Accordingly, these patients could be recognized early and provided with alternative therapeutic agents, which might improve the clinical outcome of refractory DLBCL patients.

Immunity reloaded: Deconstruction of the PD-1 axis in B cell lymphomas

Over the past decade therapies targeting the PD-1 axis with monoclonal antibodies to reinstate host immune function have revolutionized the clinical management of some cancers but have had minimal impact on others. This dichotomy is exemplified by B cell lymphomas. Whilst striking results are observed in classical Hodgkin Lymphoma (cHL) and Primary Mediastinal B Cell Lymphoma (PMBL), responses in other B cell lymphomas are infrequent. Even with cHL and PMBL, responses are not always durable and adverse effects can result in treatment discontinuation. A more nuanced approach to manipulate the PD-1 axis is required before the full benefits of PD-1 axis blockade can be realised. In this review, we provide an outline of PD-1 axis biology, including the range of cellular expression, the molecular mechanisms underlying regulation and the impacts of downstream signalling. These may permit the development of alternate strategies to PD-1 axis blockade to enhance the therapeutic efficacy in B cell lymphomas.

FDG-PET/CT after two cycles of R-CHOP in DLBCL predicts complete remission but has limited value in identifying patients with poor outcome - final result of a UK National Cancer Research Institute prospective study

The UK National Cancer Research Institute initiated a prospective study (UKCRN-ID 1760) to assess the prognostic value of early fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in diffuse large B-cell lymphoma (DLBCL). In total, 189 patients with DLBCL treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) had baseline and post-cycle-2 PET (PET2) within a quality assurance framework. Treatment decisions were based on CT; PET2 was archived for central blinded reporting after treatment completion. The association of PET2 response with end-of-treatment CT, progression-free (PFS) and overall survival (OS) was explored. The end-of-treatment complete response rate on CT was 83·9%, 75·0%, 70·5%, 40·4% and 36·4% for Deauville score (DS) 1 (n = 34), 2 (n = 39), 3 (n = 46), 4 (n = 56) and 5 (n = 14) (P < 0·001); and 64·1% and 50·0% for the maximum standardised uptake value (∆SUV_max ) of ≥66% (n = 168) and <66% (n = 21), respectively (P = 0·25). After a median 5·4 years of follow-up, the 5-year PFS was 69·4%, 72·8%, 76·7%, 71·2% and 47·6% by DS 1-5 (P = 0·01); and 72·6% and 57·1% by ∆SUV_max of ≥66% and <66% (P = 0·03), respectively. The association with DS remained in multivariable analyses, and was consistent for OS. Early complete metabolic response (DS 1-3) at interim PET/CT after two cycles of R-CHOP in DLBCL was associated with a higher end-of-treatment complete and overall response rate; however, only DS-5 patients had inferior PFS and OS.

Prognostic utility of pre-transplantation [18 F] fluorodeoxyglucose positron emission tomography/computed tomography in patients with diffuse large B-cell lymphoma who underwent rituximab, dexamethasone, high-dose cytarabine, carboplatin salvage chemotherapy

We analysed the outcomes of 62 patients with refractory/relapsed diffuse large B-cell lymphoma (rrDLBCL) who had pre-transplantation fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) after R-DHAC (rituximab, dexamethasone, high-dose cytarabine, carboplatin) salvage chemotherapy, and were evaluated using Deauville criteria and total lesion glycolysis (TLG). A positive pre-transplantation PET/CT with Deauville score of 5 was associated with shorter progression-free survival (PFS) (P = 0·01), while a Deauville score of 4 was not predictive of outcome. Only pre-transplant TLG was significantly associated with both PFS (P = 0·005) and overall survival (P = 0·03). TLG deserves to be further investigated in prospective studies.

Positron Emission Tomography Score Has Greater Prognostic Significance Than Pretreatment Risk Stratification in Early-Stage Hodgkin Lymphoma in the UK RAPID Study

PURPOSE

Accurate stratification of patients is an important goal in Hodgkin lymphoma (HL), but the role of pretreatment clinical risk stratification in the context of positron emission tomography (PET) -adapted treatment is unclear. We performed a subsidiary analysis of the RAPID trial to assess the prognostic value of pretreatment risk factors and PET score in determining outcomes.

PATIENTS AND METHODS

Patients with stage IA to IIA HL and no mediastinal bulk underwent PET assessment after three cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine; 143 PET-positive patients (PET score, 3 to 5) received a fourth doxorubicin, bleomycin, vinblastine, and dacarbazine cycle and involved-field radiotherapy, and 419 patients in complete metabolic remission were randomly assigned to receive involved-field radiotherapy (n = 208) or no additional treatment (n = 211). Cox regression was used to investigate the association between PET score and pretreatment risk factors with HL-specific event-free survival (EFS).

RESULTS

High PET score was associated with inferior EFS, before (P < .001) and after adjustment (P = .01) for baseline risk stratification. Only patients with a postchemotherapy PET score of 5 (uptake ≥ three times maximum liver uptake) had an increased risk of progression or HL-related death (hazard ratio, 9.4 v score of 3; 95% CI, 2.8 to 31.3 and hazard ratio, 6.7 v score of 4; 95% CI, 1.4 to 31.7). Patients with a PET score of 5 also had inferior progression-free and overall survival. There was no association between European Organisation for Research and Treatment of Cancer or German Hodgkin Study Group risk group and EFS, before or after adjusting for PET score (all P > .4).

CONCLUSION

In RAPID, a positive PET scan did not carry uniform prognostic weight; only a PET score of 5 was associated with inferior outcomes. This suggests that in future trials involving patients without B symptoms or mediastinal bulk, a score of 5 rather than a positive PET result should be used to guide treatment escalation in early-stage HL.

Dynamic Risk Profiling Using Serial Tumor Biomarkers for Personalized Outcome Prediction

Accurate prediction of long-term outcomes remains a challenge in the care of cancer patients. Due to the difficulty of serial tumor sampling, previous prediction tools have focused on pretreatment factors. However, emerging non-invasive diagnostics have increased opportunities for serial tumor assessments. We describe the Continuous Individualized Risk Index (CIRI), a method to dynamically determine outcome probabilities for individual patients utilizing risk predictors acquired over time. Similar to "win probability" models in other fields, CIRI provides a real-time probability by integrating risk assessments throughout a patient's course. Applying CIRI to patients with diffuse large B cell lymphoma, we demonstrate improved outcome prediction compared to conventional risk models. We demonstrate CIRI's broader utility in analogous models of chronic lymphocytic leukemia and breast adenocarcinoma and perform a proof-of-concept analysis demonstrating how CIRI could be used to develop predictive biomarkers for therapy selection. We envision that dynamic risk assessment will facilitate personalized medicine and enable innovative therapeutic paradigms.

Circulating cell-free miR-494 and miR-21 are disease response biomarkers associated with interim-positron emission tomography response in patients with diffuse large B-cell lymphoma

MicroRNA (miRNA)s are dysregulated in Diffuse large B-cell lymphoma (DLBCL), where they reflect the malignant B-cells and the immune infiltrate within the tumor microenvironment. There remains a paucity of data in DLBCL regarding cell-free (c-f) miRNA as disease response biomarkers. Immunosuppressive monocyte/macrophages, which are enriched in DLBCL, are disease response markers in DLBCL, with miRNA key regulators of their immunosuppressive function. Our aim was to determine whether plasma miRNA that reflect the activity of the malignant B-cell and/or immunosuppressive monocytes/macrophages, have value as minimally-invasive disease response biomarkers in DLBCL.

Quantification of 99 DLBCL tissues, to select miRNA implicated in immunosuppressive monocytes/macrophage biology, found miR-494 differentially elevated. In a discovery cohort (22 patients), pre-therapy c-f miR-494 and miR-21 but not miR-155 were raised relative to healthy plasma. Both miR-494 and miR-21 levels 3-6 months reduced post immuno-chemotherapy. The validation cohort (56 patients) was from a prospective clinical trial. Interestingly, in sequential samples both miRNAs decreased in patients becoming Positron Emission Tomography/Computerized Tomography (PET/CT)-ve, but not in those remaining interim-PET/CT+. Patient monocytes were phenotypically and functionally immunosuppressive with ex-vivo monocyte depletion enhancing T-cell proliferation in patient but not healthy samples. Pre-therapy monocytes showed an immunosuppressive transcriptome and raised levels of miR-494. MiR-494 was present in all c-f nanoparticle fractions but was most readily detectable in unfractionated plasma.

Circulating c-f miR-494 and miR-21 are disease response biomarkers with differential response stratified by interim-PET/CT in patients with DLBCL. Further studies are required to explore their manipulation as potential therapeutic targets.

FDG-PET/CT in the management of lymphomas: current status and future directions

FDG-PET/CT is the current state-of-the-art imaging in lymphoma and plays a central role in treatment decisions. At diagnosis, accurate staging is crucial for appropriate therapy selection: FDG-PET/CT can identify areas of lymphoma missed by CT alone and avoid under-treatment of patients with advanced disease stage who would have been misclassified as having limited stage disease by CT. Particularly in Hodgkin lymphoma, positive interim FDG-PET/CT scans are adversely prognostic for clinical outcomes and can inform PET-adapted treatment strategies, but such data are less consistent in diffuse large B-cell lymphoma. The use of quantitative FDG-PET/CT metrics using metabolic tumour volume, possibly in combination with other biomarkers, may better define prognostic subgroups and thus facilitate better treatment selection. After chemotherapy, FDG-PET/CT response is predictive of outcome and may identify a subgroup who benefit from consolidative radiotherapy. Novel therapies, in particular immunotherapies, exhibit different response patterns than conventional chemotherapy, which has led to modified response criteria that take into account the risk of transient pseudo-progression. In relapsed lymphoma, FDG-PET/CT after second-line therapy and prior to high-dose therapy is also strongly associated with outcome and may be used to guide intensity of salvage therapy in relapsed Hodgkin lymphoma. Currently, FDG-PET/CT has no role in the routine follow-up after complete metabolic response to therapy, but it remains a powerful tool for excluding relapse if patients develop clinical features suggestive of disease relapse. In conclusion, FDG-PET/CT plays major roles in the various phases of management of lymphoma and constitutes a step towards the pursuit of personalized treatment.

Circulating Tumor DNA Measurements As Early Outcome Predictors in Diffuse Large B-Cell Lymphoma

PURPOSE

Outcomes for patients with diffuse large B-cell lymphoma remain heterogeneous, with existing methods failing to consistently predict treatment failure. We examined the additional prognostic value of circulating tumor DNA (ctDNA) before and during therapy for predicting patient outcomes.

PATIENTS AND METHODS

We studied the dynamics of ctDNA from 217 patients treated at six centers, using a training and validation framework. We densely characterized early ctDNA dynamics during therapy using cancer personalized profiling by deep sequencing to define response-associated thresholds within a discovery set. These thresholds were assessed in two independent validation sets. Finally, we assessed the prognostic value of ctDNA in the context of established risk factors, including the International Prognostic Index and interim positron emission tomography/computed tomography scans.

RESULTS

Before therapy, ctDNA was detectable in 98% of patients; pretreatment levels were prognostic in both front-line and salvage settings. In the discovery set, ctDNA levels changed rapidly, with a 2-log decrease after one cycle (early molecular response [EMR]) and a 2.5-log decrease after two cycles (major molecular response [MMR]) stratifying outcomes. In the first validation set, patients receiving front-line therapy achieving EMR or MMR had superior outcomes at 24 months (EMR: EFS, 83% v 50%; P = .0015; MMR: EFS, 82% v 46%; P < .001). EMR also predicted superior 24-month outcomes in patients receiving salvage therapy in the first validation set (EFS, 100% v 13%; P = .011). The prognostic value of EMR and MMR was further confirmed in the second validation set. In multivariable analyses including International Prognostic Index and interim positron emission tomography/computed tomography scans across both cohorts, molecular response was independently prognostic of outcomes, including event-free and overall survival.

CONCLUSION

Pretreatment ctDNA levels and molecular responses are independently prognostic of outcomes in aggressive lymphomas. These risk factors could potentially guide future personalized risk-directed approaches.

Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL): A Multicenter, Randomized Phase III Trial

Purpose Interim positron emission tomography (PET) using the tracer, [¹⁸F]fluorodeoxyglucose, may predict outcomes in patients with aggressive non-Hodgkin lymphomas. We assessed whether PET can guide therapy in patients who are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Patients and Methods Newly diagnosed patients received two cycles of CHOP-plus rituximab (R-CHOP) in CD20-positive lymphomas-followed by a PET scan that was evaluated using the ΔSUV_max method. PET-positive patients were randomly assigned to receive six additional cycles of R-CHOP or six blocks of an intensive Burkitt's lymphoma protocol. PET-negative patients with CD20-positive lymphomas were randomly assigned or allocated to receive four additional cycles of R-CHOP or the same treatment with two additional doses rituximab. The primary end point was event-free survival time as assessed by log-rank test. Results Interim PET was positive in 108 (12.5%) and negative in 754 (87.5%) of 862 patients treated, with statistically significant differences in event-free survival and overall survival. Among PET-positive patients, 52 were randomly assigned to R-CHOP and 56 to the Burkitt protocol, with 2-year event-free survival rates of 42.0% (95% CI, 28.2% to 55.2%) and 31.6% (95% CI, 19.3% to 44.6%), respectively (hazard ratio, 1.501 [95% CI, 0.896 to 2.514]; P = .1229). The Burkitt protocol produced significantly more toxicity. Of 754 PET-negative patients, 255 underwent random assignment (129 to R-CHOP and 126 to R-CHOP with additional rituximab). Event-free survival rates were 76.4% (95% CI, 68.0% to 82.8%) and 73.5% (95% CI, 64.8% to 80.4%), respectively (hazard ratio, 1.048 [95% CI, 0.684 to 1.606]; P = .8305). Outcome prediction by PET was independent of the International Prognostic Index. Results in diffuse large B-cell lymphoma were similar to those in the total group. Conclusion Interim PET predicted survival in patients with aggressive lymphomas treated with R-CHOP. PET-based treatment intensification did not improve outcome.

Interobserver Agreement of Interim and End-of-Treatment 18F-FDG PET/CT in Diffuse Large B-Cell Lymphoma: Impact on Clinical Practice and Trials

We aimed to assess the interobserver agreement of interim PET (I-PET) and end-of-treatment PET (EoT-PET) using the Deauville score (DS) in first-line diffuse large B-cell lymphoma (DLBCL) patients. Methods: I-PET and EoT-PET scans of DLBCL patients were performed in the HOVON84 study (2007-2012), an international multicenter randomized controlled trial. Patients received R-CHOP14 and were randomized to receive rituximab intensification in the first 4 cycles or not. I-PET was performed after 4 cycles (for observational purposes), and EoT-PET after 6 or 8 cycles. Two independent central reviewers retrospectively scored all scans according to the DS system, masked to clinical outcomes. Results were dichotomized as negative (DS of 1-3) or positive (DS of 4-5). Besides percentage overall agreement (OA), we calculated agreement for positive and negative scores, expressed as positive agreement (PA) and negative agreement (NA), respectively. Results: 465 I-PET and 457 EoT-PET scans were centrally reviewed; baseline ¹⁸F-FDG PET or PET/CT was available in 75%-77%, and CT in the remaining cases. Percentage OA for I-PET and EoT-PET were 87.7% and 91.7% (P = 0.049), with NA of 92.0% and 95.0% (P = 0.091), and PA of 73.7% and 76.3% (P = 0.656), respectively. Conclusion: Interobserver agreement using DS in DLBCL patients in I-PET and EoT-PET yields high OA and NA. The lower PA suggests that EoT-PET/CT treatment evaluation in daily practice and I-PET-adapted trials may benefit from dual reads and central review, respectively.

Immune evasion via PD-1/PD-L1 on NK cells and monocyte/macrophages is more prominent in Hodgkin lymphoma than DLBCL

Much focus has been on the interaction of programmed cell death ligand 1 (PD-L1) on malignant B cells with programmed cell death 1 (PD-1) on effector T cells in inhibiting antilymphoma immunity. We sought to establish the contribution of natural killer (NK) cells and inhibitory CD163+ monocytes/macrophages in Hodgkin lymphoma (cHL) and diffuse large B-cell lymphoma (DLBCL). Levels of PD-1 on NK cells were elevated in cHL relative to DLBCL. Notably, CD3-CD56hiCD16-ve NK cells had substantially higher PD-1 expression relative to CD3-CD56dimCD16+ cells and were expanded in blood and tissue, more marked in patients with cHL than patients with DLBCL. There was also a raised population of PD-L1-expressing CD163+ monocytes that was more marked in patients with cHL compared with patients with DLBCL. The phenotype of NK cells and monocytes reverted back to normal once therapy (ABVD [doxorubicin 25 mg/m2, bleomycin 10 000 IU/m2, vinblastine 6 mg/m2, dacarbazine 375 mg/m2, all given days 1 and 15, repeated every 28 days] or R-CHOP [rituximab 375 mg/m2, cyclophosphamide 750 mg/m2 IV, doxorubicin 50 mg/m2 IV, vincristine 1.4 mg/m2 (2 mg maximum) IV, prednisone 100 mg/day by mouth days 1-5, pegfilgrastim 6 mg subcutaneously day 4, on a 14-day cycle]) had commenced. Tumor-associated macrophages (TAMs) expressed high levels of PD-L1/PD-L2 within diseased lymph nodes. Consistent with this, CD163/PD-L1/PD-L2 gene expression was also elevated in cHL relative to DLBCL tissues. An in vitro functional model of TAM-like monocytes suppressed activation of PD-1hi NK cells, which was reversed by PD-1 blockade. In line with these findings, depletion of circulating monocytes from the blood of pretherapy patients with cHL and patients with DLBCL enhanced CD3-CD56hiCD16-ve NK-cell activation. We describe a hitherto unrecognized immune evasion strategy mediated via skewing toward an exhausted PD-1-enriched CD3-CD56hiCD16-ve NK-cell phenotype. In addition to direct inhibition of NK cells by the malignant B cell, suppression of NK cells can occur indirectly by PD-L1/PD-L2-expressing TAMs. The mechanism is more prominent in cHL than DLBCL, which may contribute to the clinical sensitivity of cHL to PD-1 blockade.

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.

B cell lymphoma progression promotes the accumulation of circulating Ly6Clo monocytes with immunosuppressive activity

Monocytosis is considered a poor prognostic factor for many cancers, including B cell lymphomas. The mechanisms by which different monocyte subsets support the growth of lymphoma is poorly understood. Using a pre-clinical mouse model of B cell non-Hodgkin's lymphoma (B-NHL), we investigated the impact of tumor progression on circulating monocyte levels, subset distribution and their activity, with a focus on immune suppression. B-NHL development corresponded with significant expansion initially of classical (Ly6Chi) and non-classical (Ly6Clo) monocytes, with accumulation and eventual predominance of Ly6Clo cells. The lymphoma environment promoted the conversion, preferential survival and immune suppressive activity of Ly6Clo monocytes. Ly6Clo monocytes expressed higher levels of immunosuppressive genes including PD-L1/2, Arg1, IDO1 and CD163, compared to Ly6Chi monocytes. Both monocyte subsets suppressed CD8 T cell proliferation and IFN-γ production in vitro, but via different mechanisms. Ly6Chi monocyte suppression was contact dependent, while Ly6Clo monocytes suppressed via soluble mediators, including IDO and arginase. Ly6Clo monocytes could be selectively depleted in tumor-bearing hosts by liposomal doxorubicin treatment, further enhanced by co-administration of anti-4-1BB monoclonal antibody. This treatment led to a reduction in tumor growth, but failed to improve overall survival. Analogous immunosuppressive monocytes were observed in peripheral blood of diffuse large B cell lymphoma patients and actively suppressed human CD8 T cell proliferation. This study highlights a potential immune evasion strategy deployed by B cell lymphoma involving accumulation of circulating non-classical monocytes with immunosuppressive activity.

18F-FDG PET/CT in Lymphoma: Has Imaging-Directed Personalized Medicine Become a Reality?

PET/CT using ¹⁸F-FDG is an essential part of the management of patients with lymphoma. Efforts to standardize PET acquisition and reporting, including the 5-point Deauville scale, have enabled PET to become a surrogate for treatment success or failure in common lymphoma subtypes. This review summarizes the key clinical-trial evidence that supports PET-directed personalized approaches in lymphoma. PET-guided therapy has improved outcomes in Hodgkin lymphoma, using less chemotherapy and more selective radiotherapy. Attempts to intensify chemotherapy in aggressive non-Hodgkin lymphomas have, however, proved ineffective in patients treated with rituximab and chemotherapy. Trials are under way to determine whether PET can obviate consolidation radiotherapy in patients with diffuse large B-cell lymphoma and primary mediastinal B-cell lymphoma. More recently, PET has been reported to be a reliable predictor of outcome in follicular lymphoma requiring treatment, and prospective trials to test PET-guided therapy in this disease are anticipated.

FDG-PET-driven consolidation strategy in diffuse large B-cell lymphoma: final results of a randomized phase 2 study

Dose-dense induction and up-front consolidation with autologous stem cell transplantation (ASCT) remain controversial issues when treating patients with high-risk diffuse large B-cell lymphoma. GELA designed a randomized phase 2 trial evaluating the efficacy of either rituximab, doxorubicin, cyclophosphamide, vindesine, bleomycin, prednisone (R-ACVBP) or rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP14) induction and a positron emission tomography (PET)-driven ASCT or standard immunochemotherapy (SIC) consolidation in age-adjusted international prognosis index 2 (aaIPI2)-aaIPI3 patients. PET was performed at baseline, after 2 (PET2) and 4 (PET4) induction cycles, and centrally assessed using international harmonization project (IHP) criteria. PET2^-/PET4^- patients were assigned SIC, PET2⁺/PET4^- patients were assigned ASCT, and PET4⁺ patients were treated with the investigator's choice. The primary end-point was the 2007 international working group complete response (CR) rate after induction. Change in maximum standard uptake value (ΔSUVmax) after PET assessment was explored. Two hundred eleven patients were randomly assigned to R-ACVBP (n = 109) or R-CHOP14 (n = 102). PET4^-/CR rates were 53%/47% with R-ACVBP and 41%/39% with R-CHOP14 (CR 95% confidence interval [CI], 38%-67% and 28%-54%, respectively; P = .076). Consolidation in the R-ACVBP and R-CHOP14 groups was SIC in 26% and 23% of patients and ASCT in 28% and 18% of patients, respectively. PET4 positivity was higher with R-CHOP14 vs R-ACVBP (54% vs 41%; P = .08), leading to more salvage therapy (37% vs 26%; P = .07) and lower event-free survival (EFS; 4-year EFS, 31% vs 43%; P < .01), but progression-free survival (PFS) and overall survival (OS) were similar in both groups. PET2^-/PET4^- and PET2⁺/PET4^- patients had similar outcomes. Using ΔSUVmax, 79% of the patients were PET2^-/PET4^- ΔSUVmaxPET0-4 >70% was associated with better outcome (4-year PFS, 84% vs 35%; 4-year OS, 91% vs 57%; P < .0001), whatever the consolidation. Superiority of R-ACVBP over R-CHOP14 was not established, as IHP criteria did not properly reflect disease control. ΔSUVmax may help better select patients needing an alternative to SIC, including ASCT.

Interim PET-driven strategy in de novo diffuse large B-cell lymphoma: do we trust the driver?

¹⁸F-Fluorodeoxyglucose-positron emission tomography (FDG-PET) has become a central tool for both accurate initial staging and determination of prognosis after treatment of diffuse large B-cell lymphoma (DLBCL). However, the role of PET during treatment (iPET) in daily practice remains a matter of significant debate. This perspective reviews the published studies on iPET in DLBCL, including the methods used to analyze iPET, its timing, and studies of iPET-driven therapy to illuminate where daily practice may benefit from the use of iPET. When performed after 2 and/or 4 courses of immunochemotherapy, iPET has a very good negative predictive value, utilizing both visual (qualitative) and semiquantitative methods. The visual method accurately predicts outcome for patients with limited disease. The semiquantitative method, eg, the change of the difference of maximum standardized uptake value (ΔSUVmax), is for patients with advanced DLBCL, for whom iPET identifies patients with very good outcome with continuation of standard therapy. A low ΔSUVmax also helps identify patients with a risk for relapse averaging 50% and warrants review of their scheduled therapy. To date, no trial has demonstrated the superiority of an iPET-driven strategy in DLBCL. However, the very good negative and good positive predictive values of iPET support its use in daily practice as a better predictive tool than contrast-enhanced computed tomographic scan for therapeutic decision making.