Caron A. Jacobson

Immune Reconstitution after Double Umbilical Cord Blood Stem Cell Transplantation: Comparison with Unrelated Peripheral Blood Stem Cell Transplantation

Double umbilical cord blood (DUCB) transplantation is an accepted transplantation strategy for patients without suitable human leukocyte antigen (HLA) matched donors. However, DUCB transplantation is associated with increased morbidity and mortality because of slow recovery of immunity and a high risk of infection. To define the differences in immune reconstitution between DUCB transplantation and HLA matched unrelated donor (MUD) transplantation, we performed a detailed, prospective analysis of immune reconstitution in 42 DUCB recipients and 102 filgrastim-mobilized unrelated peripheral blood stem cell recipients. Reconstitution of CD3 T cells was significantly delayed in the DUCB cohort compared with the MUD cohort for 1 to 6 months posttransplantation (P < .001), including naive (CD45RO-) and memory (CD45RO+) CD4 T cells, regulatory (CD4CD25) T cells, and CD8 T cells. In contrast, CD19 B cells recovered more rapidly in the DUCB cohort and numbers remained significantly greater from 3 to 24 months after transplantation (P = .001). CD56CD16 natural killer (NK) cells also recovered more rapidly in DUCB recipients and remained significantly greater from 1 to 24 months after transplantation. B cell activating factor (BAFF) levels were higher in the DUCB cohort at 1 month (P < .001), were similar in both cohorts at 3 and 6 months, and were lower in the DUCB cohort at 12 months (P = .002). BAFF/CD19 B cell ratios were lower in the DUCB cohort at 3 (P = .045), 6 (P = .02), and 12 months (P = .002) after transplantation. DUCB recipients had more infections within the first 100 days after transplantation (P < .001), and there was less chronic graft-versus-host disease (P < .001), but there were no differences in cumulative incidence of relapse, nonrelapse death, progression-free survival, or overall survival between the 2 groups. These results suggest that increased risk of infections is specifically associated with delayed reconstitution of all major T cell subsets, but the increased risk is limited to the first 3 months after DUCB transplantation. There is no increased risk of relapse, suggesting that graft-versus-leukemia activity is maintained. Early reconstitution of B cells and NK cells may, in part, account for these findings.

Idelalisib given front-line for treatment of chronic lymphocytic leukemia causes frequent immune-mediated hepatotoxicity

Idelalisib is a small-molecule inhibitor of PI3Kδ with demonstrated efficacy for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). To evaluate idelalisib as front-line therapy, we enrolled 24 subjects in a phase 2 study consisting of 2 months of idelalisib monotherapy followed by 6 months of combination therapy with idelalisib and the anti-CD20 antibody ofatumumab. After a median follow-up period of 14.7 months, hepatotoxicity was found to be a frequent and often severe adverse event. A total of 19 subjects (79%) experienced either grade ≥1 ALT or AST elevation during the study, and 13 subjects (54%) experienced grade ≥3 transaminitis. The median time to development of transaminitis was 28 days, occurring before ofatumumab introduction. Younger age and mutated immunoglobulin heavy chain status were significant risk factors for the development of hepatotoxicity. Multiple lines of evidence suggest that this hepatotoxicity was immune mediated. A lymphocytic infiltrate was seen on liver biopsy specimens taken from 2 subjects with transaminitis, and levels of the proinflammatory cytokines CCL-3 and CCL-4 were higher in subjects experiencing hepatotoxicity. All cases of transaminitis resolved either by holding the drug, initiating immunosuppressants, or both, and rates of recurrent toxicity were lower in patients taking steroids when idelalisib was reinitiated. A decrease in peripheral blood regulatory T cells was seen in patients experiencing toxicity on therapy, which is consistent with an immune-mediated mechanism. These results suggest that caution should be taken as drugs within this class are developed for CLL, particularly in younger patients who have not received prior disease-specific therapy. This study was registered at www.clinicaltrials.gov as #NCT02135133.

The Public Repository of Xenografts Enables Discovery and Randomized Phase II-like Trials in Mice

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease.

Detection of circulating tumour DNA in patients with aggressive B-cell non-Hodgkin lymphoma

Current methods for detecting the presence of disease in patients with diffuse large B cell lymphoma (DLBCL) or mediastinal large B-cell lymphoma (MLBCL) rely primarily on imaging methods, which are associated with significant cost and radiation exposure. Very few patients with DLBCL have evidence of circulating disease using flow cytometric assays (Mancuso et al, 2010). This has so far precluded the development of minimal residual disease (MRD) assessment tools in those diseases, in contrast to tumours with a circulating component, where MRD assays are emerging as important methods (Ferrero et al, 2011). The availability of high-throughput sequencing techniques now provides an opportunity to probe for the presence of very small amounts of circulating tumour genetic material in peripheral blood (PB). If sequencing-based methods can reliably detect circulating disease, they could eventually find a role in the treatment and monitoring of patients with those tumours. We present here a pilot study of a sequencing method designed to examine whether tumour DNA is detectable in patients with newly diagnosed DLBCL/MLBCL, and whether it becomes undetectable after therapy. Tumour samples obtained from PB samples and formalin-fixed paraffin-embedded (FFPE) or frozen tissue were analysed using the Sequenta LymphoSIGHT method (Sequenta Inc., South San Francisco, CA, USA), as previously described (Faham et al, 2012a, 2012b). Briefly, genomic DNA was extracted from tumour cells, peripheral blood mononuclear cells (PBMCs) or plasma, amplified using locus-specific primer sets for IGH and IGK rearrangements, and sequenced. A frequency >5% in the diagnostic tumour sample was considered to represent one of the tumour clonotypes; the frequency of the tumour clonotype(s) in PB was calculated relative to the total number of reads in the sample. We approached consecutive patients with newly diagnosed DLBCL or MLBCL who presented for care at Dana-Farber Cancer Institute (DFCI). Independently, five patients with DLBCL who had banked tumour and blood samples at the M.D. Anderson Cancer Center (MDACC) were enrolled on a similar study. Written informed consent was obtained from all patients. All patients had a sample of tumour from their diagnostic biopsy sent to Sequenta Inc. for analysis. We collected a sample of whole blood before the first cycle of therapy; when possible, we also collected a sample after the conclusion of therapy (only in the DFCI cohort). Seventeen patients were enrolled on this study (Table I). None of 13 patients biopsied had bone marrow involvement. At least one dominant tumour clonotype could be established from the diagnostic biopsy for all 16 patients with sufficient amounts of amplifiable DNA. The diagnostic biopsy sample for one patient had <0.3 ng of DNA, and a dominant tumour clonotype was not identified. Among the 16 patients with an established tumour clonotype, circulating tumour DNA could be detected pre-treatment in plasma in 11 of the 16 (69%, 90% confidence interval [CI] 45–87%), in PBMCs in eight of the 16 (50%, 90%CI 28–72%), and in either in 13 of the 16 (81%, 90%CI 58–95%) (Table I, Fig 1A, B). The three patients in whom no DNA could be detected at diagnosis all had stage I disease and had no evidence of disease by positron emission tomography-computerized tomography (PET-CT) after their diagnostic procedure at the time that the study sample was drawn. Therefore, tumour DNA was detected in all 13 (100%) of patients with evidence of fluorodeoxyglucose-avid disease at the time of sample collection. There was no apparent correlation between the level of circulating tumour DNA and clinical characteristics including histology, stage, burden of disease, or International Prognostic Index (The International Non-Hodgkin’s Lymphoma Prognostic Factors Project, 1993). There was also no association between the presence or level of circulating DNA and lactate dehydrogenase elevation pre-treatment. All patients were treated with chemo-immunotherapy; one patient with MLBCL also received radiotherapy. Seven patients from the DFCI cohort returned for collection of post-therapy samples; the remaining received their care outside of DFCI and did not return for follow-up. At a median follow-up of 269 (range, 220–281) days from the beginning of therapy, none of the patients have relapsed. Among the seven evaluable patients, six (86%, 90%CI 48–99%) had no detectable circulating tumour DNA at the conclusion of chemoimmunotherapy (Table I, Fig 1C). Using a novel high-throughput sequencing technique, we could determine the dominant tumour clonotype in 94% of 17 patients with DLBCL/MLBCL from routine diagnostic tumour samples, and in 100% of those with adequate amount of tumour material for analysis. Among those patients, 81% had detectable circulating tumour DNA in plasma or PBMCs; the proportion was 100% among the patients with evidence of disease by PET-CT scan after their diagnostic surgical biopsy. Furthermore, the tumour DNA correspondence

Prognostic factors for patients with diffuse large B cell lymphoma and transformed indolent lymphoma undergoing autologous stem cell transplantation in the positron emission tomography era.

In the positron emission tomography (PET) era, traditional prognostic factors may not apply for patients with relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL) undergoing autologous stem cell transplantation (ASCT). Moreover, little is known about prognostic factors in patients transplanted for transformed indolent lymphoma (TIL). We conducted a retrospective study of 143 patients with R/R DLBCL and TIL who were transplanted in the last decade and had a post‐salvage PET scan. We examined prognostic factors in both groups, and constructed a prognostic score for DLBCL patients. For patients with DLBCL, post‐salvage PET response was an important prognostic factor. Advanced age and symptomatic relapse were also significantly associated with outcome. A simple score could stratify patients into three risk groups with 4‐year post‐ASCT overall survival of 84%, 59%, and 10%, and 4‐year progression‐free survival of 67%, 41% and 0% (P < 0·0001 for both). However, none of those factors (including PET response to salvage) appeared relevant for patients with TIL, despite their comparable overall outcome. Our prognostic score for DLBCL patients undergoing ASCT may be useful for prognostication, for stratification in clinical trials, and to motivate the design of new strategies for patients in the high‐risk group, who may not derive benefit from standard ASCT.

Relapsed or Refractory Double-Expressor and Double-Hit Lymphomas Have Inferior Progression-Free Survival After Autologous Stem-Cell Transplantation

Purpose Double-hit lymphomas (DHLs) and double-expressor lymphomas (DELs) are subtypes of diffuse large B-cell lymphoma (DLBCL) associated with poor outcomes after standard chemoimmunotherapy. Data are limited regarding outcomes of patients with relapsed or refractory (rel/ref) DEL or DHL who undergo autologous stem-cell transplantation (ASCT). We retrospectively studied the prognostic impact of DEL and DHL status on ASCT outcomes in patients with rel/ref DLBCL. Methods Patients with chemotherapy-sensitive rel/ref DLBCL who underwent ASCT at two institutions and in whom archival tumor material was available were enrolled. Immunohistochemistry for MYC, BCL2, and BCL6 and fluorescence in situ hybridization (FISH) for MYC were performed. In cases with MYC rearrangement or copy gain, FISH for BCL2 and BCL6 was also performed. Results A total of 117 patients were included; 44% had DEL and 10% had DHL. DEL and DHL were associated with inferior progression-free survival (PFS), and DHL was associated with poorer overall survival (OS). The 4-year PFS in patients with DEL compared with those with non-DEL was 48% versus 59% ( P = .049), and the 4-year OS was 56% versus 67% ( P = .10); 4-year PFS in patients with DHL compared with those with non-DHL was 28% versus 57% ( P = .013), and 4-year OS was 25% versus 61% ( P = .002). The few patients with concurrent DEL and DHL had a poor outcome (4-year PFS, 0%). In multivariable models, DEL and DHL were independently associated with inferior PFS, whereas DHL and partial response ( v complete response) at transplant were associated with inferior OS. Conclusion DEL and DHL are both associated with inferior outcomes after ASCT in patients with rel/ref DLBCL. Although ASCT remains a potentially curative approach, these patients, particularly those with DHL, are a high-risk subset who should be targeted for investigational strategies other than standard ASCT.

How I treat Burkitt lymphoma in adults

Burkitt lymphoma (BL) is an aggressive B-cell non-Hodgkin lymphoma that is almost uniformly associated with translocations involving the gene for MYC on chromosome 8. The 3 subtypes of BL, endemic, sporadic, and immunodeficiency-associated, differ from epidemiologic and clinical perspectives but may be genetically similar. Prompt administration of multiagent immunochemotherapy regimens is associated with favorable outcomes for the majority of patients. Survival is inferior in older patients, likely reflecting increased therapy-related toxicity, possibly resulting in decreased treatment intensity. Central nervous system prophylaxis, tumor lysis prevention and treatment, and management of infectious complications from myelosuppressive regimens are critical. Prognosis of refractory or relapsed disease is poor and patients are best treated on clinical trials when available.

A phase 2 study of Rituximab-Bendamustine and Rituximab-Cytarabine for transplant-eligible patients with mantle cell lymphoma.

Chemoimmunotherapy followed by autologous stem cell transplantation (ASCT) is a standard therapy for transplant‐eligible patients with newly diagnosed mantle cell lymphoma (MCL). The achievement of complete remission (CR) and minimal residual disease (MRD) negativity are associated with better outcomes. We tested an induction regimen of rituximab/bendamustine followed by rituximab/high‐dose cytarabine (RB/RC). This phase 2 study (NCT01661881) enrolled 23 transplant‐eligible patients aged 42–69, of whom 70% were MCL international prognostic index low‐risk. Patients received three cycles of RB followed by three cycles of RC. The primary endpoint of the trial was the rate of CR after six cycles of therapy, with a rate of 75% considered promising. 96% of patients achieved a CR/unconfirmed CR after treatment, meeting the primary objective. One patient progressed on study, one declined ASCT in CR, and the remaining 21 underwent successful stem cell collection and ASCT. After a median follow‐up of 13 months, the progression‐free survival rate was 96%. Among 15 MRD‐evaluable patients who completed treatment, 93% achieved MRD negativity after RB/RC. In conclusion, RB/RC achieves very high CR and MRD negativity rates in transplant‐eligible patients, with a favourable safety profile. RB/RC warrants further comparative studies, and may become a useful alternative to RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone)‐based induction regimens in this patient population.

Post-Transplantation B Cell Activating Factor and B Cell Recovery before Onset of Chronic Graft-versus-Host Disease

Excessive levels of B cell activating factor (BAFF) are found in patients with active chronic graft-versus-host disease (cGVHD). In mice, BAFF has been shown to be essential for B cell recovery after myeloablation. To assess how BAFF levels relate to transplantation factors and subsequent development of cGVHD, we prospectively monitored 412 patients in the first year after allogeneic peripheral blood or bone marrow hematopoietic stem cell transplantation (HSCT) and censored data at time of cGVHD onset. In patients who did not develop cGVHD, we affirmed a temporal pattern of gradually decreasing BAFF levels as B cell numbers increase after myeloablative conditioning. In contrast, after reduced-intensity conditioning, BAFF levels remained high throughout the first post-HSCT year, suggesting that the degree of myeloablation resulted in delayed B cell recovery associated with persistence of higher BAFF levels. Given that high BAFF/B cell ratios have been associated with active cGVHD, we examined differences in early BAFF/B cell ratios and found significantly different BAFF/B cell ratios at 3 months post-HSCT only after myeloablative conditioning in patients who subsequently developed cGVHD. In addition to HSCT conditioning type, the use of sirolimus was significantly associated with higher BAFF levels after HSCT, and this also was potentially related to lower B cell numbers. Taken together, our results are important for interpreting BAFF measurements in cGVHD biomarker studies.

HIV-Associated Hodgkin's Lymphoma: Prognosis and Therapy in the Era of cART

Patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) are at increased risk for developing Hodgkins lymphoma (HL), a risk that has not decreased despite the success of combination antiretroviral therapy (cART) in the modern era. HIV-associated HL (HIV-HL) differs from HL in non-HIV-infected patients in that it is nearly always associated with Epstein-Barr virus (EBV) and more often presents with high-risk features of advanced disease, systemic “B” symptoms, and extranodal involvement. Before the introduction of cART, patients with HIV-HL had lower response rates and worse outcomes than non-HIV-infected HL patients treated with conventional chemotherapy. The introduction of cART, however, has allowed for the delivery of full-dose and dose-intensive chemotherapy regimens with improved outcomes that approach those seen in non-HIV infected patients. Despite these significant advances, HIV-HL patients remain at increased risk for treatment-related toxicities and drug-drug interactions which require careful attention and supportive care to insure the safe administration of therapy. This paper will address the modern diagnosis, risk stratification, and therapy of HIV-associated HL.