Leung, Nelson

Background Membranous nephropathy (MN) is a common cause of proteinuria in patients receiving a hematopoietic stem cell transplant (HSCT). The target antigen in HSCT-associated MN is unknown. Methods We performed laser microdissection and tandem mass spectrometry (MS/MS) of glomeruli from 250 patients with PLA2R-negative MN to detect novel antigens in MN. This was followed by immunohistochemical (IHC)/immunofluorescence (IF) microscopy studies to localize the novel antigen. Western blot analyses using serum and IgG eluted from frozen biopsy specimen to detect binding of IgG to new 'antigen'. Results MS/MS detected a novel protein, protocadherin FAT1 (FAT1), in nine patients with PLA2R-negative MN. In all nine patients, MN developed after allogeneic HSCT (Mayo Clinic discovery cohort). Next, we performed MS/MS in five patients known to have allogeneic HSCT-associated MN (Cedar Sinai validation cohort). FAT1 was detected in all five patients by MS/MS. The total spectral counts for FAT1 ranged from 8 to 39 (mean±SD, 20.9±10.1). All 14 patients were negative for known antigens of MN, including PLA2R, THSD7A, NELL1, PCDH7, NCAM1, SEMA3B, and HTRA1. Kidney biopsy specimens showed IgG (2 to 3+) with mild C3 (0 to 1+) along the GBM; IgG4 was the dominant IgG subclass. IHC after protease digestion and confocal IF confirmed granular FAT1 deposits along the GBM. Lastly, Western blot analyses detected anti-FAT1 IgG and IgG4 in the eluate obtained from pooled frozen kidney biopsy tissue and in the serum of those with FAT1-asssociated MN, but not from those with PLA2R-associated MN. Conclusions FAT1-associated MN appears to be a unique type of MN associated with HSCT. FAT1-associated MN represents a majority of MN associated with HSCT.

Chronic lymphocytic leukemia (CLL) is the most common leukemia in developed countries. Kidney injuries related to CLL can occur via several mechanisms. Approximately 30%–40% of CLL patients with a kidney biopsy have monoclonal-protein related lesions. However, such lesions mostly involve glomeruli with only rare instances of tubule-interstitial disorders. There is only a single case report of a CLL patient who presented with crystalline light chain proximal tubulopathy (LCPT). Fanconi syndrome (FS) may provide clinical clues in these patients. We report a case of a CLL patient who presented with hypokalemia in the setting of advanced kidney failure in which serum monoclonal IgG kappa was detected. The patient demonstrated typical signs and symptoms of FS. The urinary retinol binding protein was also extremely elevated (638 times upper normal limit). A kidney biopsy revealed non-crystalline LCPT with CLL infiltration. FS in CLL is an extremely rare presentation, as only four cases had been previously reported. Of these, only a single case had crystalline LCPT. Our case is the first report of non-crystalline LCPT in a CLL patient. Obinutuzumab and Venetoclax were started to address the CLL, and an improvement in kidney function was noted thereafter.

Abstract Multiple myeloma (MM) is a plasma cell malignancy that is characterized by diverse clinical presentations. Although biochemical assessment of disease activity is commonly used to monitor treatment response, findings on magnetic resonance imaging and positron emission tomography (PET)/computed tomography (CT), among other imaging modalities, have proven to harbor prognostic value. We sought to corroborate these findings by examining the prognostic significance of fluorodeoxyglucose PET/CT scanning in the setting of newly diagnosed MM. We retrospectively analyzed 195 patients with a PET/CT available at diagnosis and at 6 months posttreatment to examine their value as an adjuvant metric to conventional hematologic responses in terms of time to next treatment (TTNT) and overall survival (OS). The median TTNT and OS for the entire cohort were 24.6 months (95% confidence interval [CI], 20.4-29.1) and 79 months (95% CI, 63.1-119.1), respectively. When comparing PET/CT negative (−) with PET/CT positive (+) patients, we found significantly prolonged median TTNT (55.2 vs 17.8 months, P < .0001) and OS (unreached vs 60.8 months, P < .0001) in the former group. We then examined the additive value of PET/CT on the hematologic response achieved at 6 months and found that PET/CT (−) is associated with significantly increased median TTNT and OS for the very good partial response (VGPR) group and the less than VGPR group. Importantly, PET/CT retained prognostic significance after adjusting for multiple other predictive variables. We conclude that a PET/CT (−) at 6 months confers a significant prognostic advantage for patients with newly diagnosed MM and adds significant value to the hematologic response assessment.

Clinical success with intravenous (IV) oncolytic virotherapy (OV) has to date been anecdotal. Here, we conducted a phase 1 clinical trial of systemic OV therapy and investigated the mechanisms of action in responding T-cell lymphoma (TCL) patients. A single IV dose of VSV-IFNβ-NIS was administered to patients with relapsed refractory hematologic malignancies to determine safety and efficacy across 4 dose levels (DL). Correlative studies were undertaken to evaluate viremia, virus shedding, virus replication and immune responses. Fifteen patients received VSV-IFNβ-NIS (7 multiple myeloma, 7 TCL, 1 acute myeloid leukemia); 3 patients were treated at each DL1 through DL3 (0.05, 0.17, and 0.5 x 1011 TCID50), and 6 at DL4 (1.7 x 1011 TCID50). There were no dose limiting toxicities. 3 of 7 patients with TCL had RECIST responses: a 3-month PR at DL2, a 6-month PR and a durable CR ongoing at 20 months at DL4. Viremia peaked at the end of infusion and no infectious virus shedding was detected. Plasma interferon-β levels, a biomarker of VSV-IFNβ-NIS replication, peaked between 4h and 48h post infusion. The patient with CR had robust viral replication with increased ell free DNA in her plasma, a very high peak IFNβ level of 18,213 pg/ml, a strong anti-VSV neutralizing antibody response, and increased numbers of tumor reactive T-cells. VSV-IFNβ-NIS as a single agent was effective in patients with TCL resulting in durable disease remissions in heavily pretreated patients. Correlative analyses suggest that responses may be due to a combination of direct oncolytic tumor destruction and immune-mediated tumor control. Further clinical testing is warranted. (This trial is registered at www.clinicaltrials.gov as NCT03017820).

AbstractCastleman disease (CD) is a rare lymphoproliferative disease characterized by diverse clinical and pathologic features. Due to its rarity, there are limited studies comparing currently available therapies. The role of autologous stem cell transplantation (ASCT) in CD has not yet been established. In this paper, we describe the clinical characteristics, treatment choices, and outcomes in 34 Mayo Clinic patients diagnosed with multicentric CD from July 1, 2003 to April 30, 2018. Eighteen patients (53%) also met the criteria for POEMS, including 14 with the osteosclerotic variant. The first‐line treatments included: steroid monotherapy (4), cytotoxic chemotherapy (6), rituximab alone (8) or with chemotherapy (2), anti‐IL6 treatment (3), and ASCT (10). The median follow‐up was 4.8 (range: 0.1–15.2) years. The 5‐ and 10‐year overall survival rates were 84% and 71%, respectively. Sixteen patients received high‐dose chemotherapy followed by ASCT during their disease course. Among those, 14 had multicentric CD associated with POEMS. There were no transplant‐related deaths. All patients had at least a partial response to ASCT, most of whom achieved a complete response. The favorable outcomes seen with ASCT in this cohort suggest that transplantation may have a role in multicentric CD, particularly for patients with multicentric CD associated with POEMS.

AbstractAchievement of a complete response (CR) in multiple myeloma (MM) correlates with improvement in survival outcomes; however, its impact on prognostic variables at baseline outside of clinical trial settings is not well described. We sought to determine the impact of achieving a CR within 2 years from diagnosis, its effect on the prognostic value of fluorescence in situ hybridization (FISH) and International Staging System (ISS) risk, and examined additional predictors of outcome among those achieving a CR in a routine clinical setting. We evaluated 1869 newly diagnosed MM patients who had ≥ 2 monoclonal protein immunofixation studies in the serum and urine available within 24 months from diagnosis, categorizing those with ≥ 2 negative serum and urine immunofixations as achieving CR. With a landmark at 24 months, median progression‐free survival (PFS) for CR versus non‐CR patients was 29.8 versus 20.9 months (p ≤ .0002); median overall survival (OS) was 104 versus 70 months (p < .0001). The impact of achieving a CR was retained after adjusting for FISH, ISS, sex, transplant status, and involved heavy chain. Baseline FISH and ISS stage were not associated with PFS or OS among patients achieving a CR. The following variables were found as predictors of inferior OS within the CR cohort: age > 75 years, male gender, hypoalbuminemia, and non‐immunoglobulin G involved heavy chain. Our study confirms that achievement of CR within 2 years from diagnosis is associated with improvement in survival outcomes and neutralization of the impact of FISH and ISS risk, thereby confirming observations from the clinical trial setting among a clinical practice cohort.

Background: Peptide receptor radionuclide therapy with 177 Lu-dotatate is a novel therapy for metastatic neuroendocrine cancers. It undergoes reabsorption at the proximal tubule; after the breakdown of the peptide fragment, 177 Lu is retained and continues its decay process exposing the nephron to continuous low dose radiation. Pivotal NETTER-1 trial did not include patients with eGFR <50 and so its effects in CKD patients is not known. Methods: We performed a retrospective chart review of all consecutive adult patients that received 177 Lu-dotatate over 1 year at Mayo Clinic, Rochester. We analyzed renal and hematological laboratory data obtained prior to each of four treatment cycles and at 3- and 6-month post completion of all treatment. We defined CKD as eGFR <60 ml/min and AKI as creatinine increase of ⩾0.3 from baseline by AKIN criteria. Results: Overall 86 patients were included in the study with 39 (45%) with known CKD. About three patients had CKD, four with eGFR of 20–30 ml/min. About 4 (4.6%) patients had AKI and the predominant cause being hypotension. Among the CKD patients the average eGFR improved after the first cycle of PRRT therapy from baseline of 49 (13) to 53.5 (17) ml/min ( p = 0.01) with no significant decline of renal function noted at 3- and 6-months post treatment follow up. Rate of thrombocytopenia and leukopenia were significantly more in the CKD patients starting even after single treatment. No drug dose correlation was noted. Conclusion: Patients with CKD are at a higher risk of hematological toxicity especially with thrombocytopenia and require close monitoring and ongoing dose adjustment. Ongoing safety studies to assess the long-term impact of 177 Lu-dotatate on the kidney are needed.

AbstractThromboses are prevalent in POEMS syndrome, but few risk factors for POEMS‐associated thrombosis have been identified. The objective of this study is to identify novel risk factors for POEMS‐associated thrombosis. In this retrospective cohort of 230 POEMS patients, 27% developed thrombosis. Arterial events were slightly more common than venous. Stroke accounted for 26% of all thromboses and 53% of arterial events. There were differences in baseline features between the thrombosis group and the no thrombosis group, and these were driven by patients with arterial thrombosis. Risk factors for arterial thrombosis included thrombocytosis, elevated hemoglobin/hematocrit, extravascular volume overload, and splenomegaly. Hyperprolactinemia appeared to be a risk factor for venous thrombosis. The risk of thrombosis was most striking among men with elevated hemoglobin (32% vs. 5%, p < .001) and hematocrit (42% vs. 5%, p < .001) compared to men without. Most thromboses occurred prior to POEMS directed therapy, and most that occurred during therapy happened within 3 months of diagnosis. Twenty‐one percent of patients with thrombosis had recurrence. In recognition of high overall rates of thrombosis in this population, all patients with POEMS syndrome should receive prophylactic antiplatelet therapy, and clinicians should consider anticoagulation in patients with risk factors for POEMS‐associated thrombosis.

AbstractGain of 1q22 at diagnosis portends poorer outcomes in multiple myeloma (MM), but the prognostic significance of acquired 1q22 gain is unknown. We identified 63 MM patients seen at Mayo Clinic from 1/2004 to 12/2019 without 1q22 gain at diagnosis who acquired it during follow up and compared them to 63 control patients who did not acquire 1q22 gain with similar follow up. We also compared outcomes in the acquired 1q22 gain group with outcomes in 126 patients with 1q22 gain present at diagnosis. The incidence of acquired 1q22 gain was 6.1% (median follow‐up 6.8 years); median time to acquisition was 5.0 years (range: 0.7–11.5 years). Abnormalities on baseline fluorescence in situ hybridization (FISH) included trisomies (54%) and monosomy 13 (39%); 16 (25%) had high‐risk (HR) translocations or del(17p). Median progression‐free survival with front line therapy was 29.5 months in patients with acquired 1q22 gain, versus 31.4 months in control patients (p = .34) and 31.2 months in patients with de novo 1q22 gain (p = .04). Median overall survival (OS) from diagnosis was 10.9 years in patients with acquired 1q22 gain, versus 13.0 years in control patients (p = .03) and 6.3 years in patients with de novo 1q22 gain (p = .01). Presence of HR FISH at baseline increased risk of 1q22 gain acquisition. We demonstrate that acquisition of 1q22 gain is a significant molecular event in MM, associated with reduced OS. Among HR patients for whom this clonal evolution is determined, a risk‐adapted approach and/or clinical trial should be considered.

Key Points Post-HSCT hemoglobinuria was associated with graft type (BMT+Cord). Post-HSCT hemoglobinuria was associated with early (48–72 hours) post-HSCT AKI. Graft type (BMT+Cord) was associated with AKI among patients with hemoglobinuria. Background Information on risk factors of hemoglobinuria after hematopoietic stem-cell transplant (HSCT) and its association with AKI, mortality, and engraftment is limited. Methods We conducted a retrospective cohort study on all consecutive adults that underwent HSCT from January 6, 1999, to November 6, 2017. The study included 6039 patients that underwent bone marrow transplantation (BMT), umbilical cord blood, and peripheral blood stem-cell transplantation (PBSCT). Results Early post-HSCT, AKI occurred in 393 (7%) patients, and 52 (0.9%) patients had post-HSCT hemoglobinuria. Post-HSCT hemoglobinuria was associated with graft type (BMT+Cord), underlying disease (lymphoma, acute leukemia), and fludarabine-based conditioning regimen. Post-HSCT hemoglobinuria was associated with early (48–72 hours) post-HSCT AKI. Graft type (BMT+Cord) was associated with AKI among patients with hemoglobinuria. AKI in patients with hemoglobinuria was associated with delayed platelet engraftment and delayed WBC engraftment but not 100-day mortality. Conclusion Close monitoring is recommended in this patient group to facilitate a good engraftment outcome.