Safety of extended pirtobrutinib exposure in relapsed and/or refractory B-cell malignancies.

INTRODUCTION: Pirtobrutinib, a highly selective, non-covalent (reversible) Bruton tyrosine kinase inhibitor, has demonstrated promising efficacy in B-cell malignancies and is associated with low rates of discontinuation and dose reduction. Pirtobrutinib is administered until disease progression or toxicity, necessitating an understanding of the safety profile in patients with extended treatment. METHODS: Here we report the safety of pirtobrutinib in patients with relapsed/refractory B-cell malignancies with extended (≥12-months) drug exposure from the BRUIN trial. Assessments included median-time-to-first-occurrence of adverse events (AEs), dose reductions, and discontinuations due to treatment-emergent AEs (TEAEs) and select AEs of interest (AESIs). RESULTS: Of 773 patients enrolled, 326 (42%) received treatment for ≥12 months. In the extended exposure cohort, the median-time-on-treatment was 19 months. The most common all-cause TEAEs were fatigue (32%) and diarrhea (31%). TEAEs leading to dose reduction occurred in 23 (7%) and discontinuations in 11 (3%) extended exposure patients. One patient had a fatal treatment-related AE (COVID-19 pneumonia). Infections (73.0%) was the most common AESI with a median-time-to-first-occurrence of 7.4 months. Majority of TEAEs and AESIs occurred during the first-year of therapy. CONCLUSIONS: Pirtobrutinib therapy continues to demonstrate an excellent safety profile amenable to long-term administration without evidence of new or worsening toxicity signals.

Tabelecleucel for EBV+ PTLD following allogeneic HCT or SOT in a multicenter expanded access protocol.

Patients with Epstein-Barr virus (EBV)-positive post-transplant lymphoproliferative disease (EBV+ PTLD) in whom initial treatment fails have few options and historically low median overall survival (OS) of 0.7 months following allogeneic hematopoietic cell transplant (HCT) and 4.1 months following solid organ transplant (SOT). Tabelecleucel is an off-the-shelf, allogeneic EBV-specific cytotoxic T-lymphocyte immunotherapy for EBV+ PTLD. Previous single-center experience showed responses in patients with EBV+ PTLD following HCT or SOT. We now report outcomes from a multicenter expanded access protocol (NCT02822495) in HCT (n = 14) and SOT (n = 12) recipients treated with tabelecleucel for EBV+ PTLD that was relapsed/refractory to rituximab ± chemotherapy. The investigator-assessed objective response rate was 65.4% overall (including 38.5% with a complete and 26.9% with a partial response), 50.0% in HCT, and 83.3% in SOT. The estimated 1- and 2-year OS rates (95% CI) were both 70.0% (46.5, 84.7) overall, both 61.5% (30.8, 81.8) in HCT, and both 81.5% (43.5, 95.1) in SOT (median follow-up: 8.2, 2.8, and 22.5 months, respectively). Patients responding to tabelecleucel had higher 1- and 2-year OS rates (94.1%) than non-responders (0%). Treatment was well tolerated with no reports of tumor flare, cytokine release syndrome, or rejection of marrow and SOT. Results demonstrate clinically meaningful outcomes across a broad population treated with tabelecleucel, indicating a potentially transformative and accessible treatment advance for relapsed/refractory EBV+ PTLD following HCT or SOT.

Pirtobrutinib after a Covalent BTK Inhibitor in Chronic Lymphocytic Leukemia.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) have poor outcomes after the failure of covalent Bruton's tyrosine kinase (BTK) inhibitor treatment, and new therapeutic options are needed. Pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor, was designed to reestablish BTK inhibition. METHODS: We conducted a phase 1-2 trial in which patients with relapsed or refractory B-cell cancers received pirtobrutinib. Here, we report efficacy results among patients with CLL or SLL who had previously received a BTK inhibitor as well as safety results among all the patients with CLL or SLL. The primary end point was an overall response (partial response or better) as assessed by independent review. Secondary end points included progression-free survival and safety. RESULTS: A total of 317 patients with CLL or SLL received pirtobrutinib, including 247 who had previously received a BTK inhibitor. Among these 247 patients, the median number of previous lines of therapy was 3 (range, 1 to 11), and 100 patients (40.5%) had also received a B-cell lymphoma 2 (BCL2) inhibitor such as venetoclax. The percentage of patients with an overall response to pirtobrutinib was 73.3% (95% confidence interval [CI], 67.3 to 78.7), and the percentage was 82.2% (95% CI, 76.8 to 86.7) when partial response with lymphocytosis was included. The median progression-free survival was 19.6 months (95% CI, 16.9 to 22.1). Among all 317 patients with CLL or SLL who received pirtobrutinib, the most common adverse events were infections (in 71.0%), bleeding (in 42.6%), and neutropenia (in 32.5%). At a median duration of treatment of 16.5 months (range, 0.2 to 39.9), some adverse events that are typically associated with BTK inhibitors occurred relatively infrequently, including hypertension (in 14.2% of patients), atrial fibrillation or flutter (in 3.8%), and major hemorrhage (in 2.2%). Only 9 of 317 patients (2.8%) discontinued pirtobrutinib owing to a treatment-related adverse event. CONCLUSIONS: In this trial, pirtobrutinib showed efficacy in patients with heavily pretreated CLL or SLL who had received a covalent BTK inhibitor. The most common adverse events were infections, bleeding, and neutropenia. (Funded by Loxo Oncology; BRUIN ClinicalTrials.gov number, NCT03740529.).

Pirtobrutinib in Covalent Bruton Tyrosine Kinase Inhibitor Pretreated Mantle-Cell Lymphoma.

PURPOSE: Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). We report the safety and efficacy of pirtobrutinib in patients with covalent Bruton tyrosine kinase inhibitor (cBTKi) pretreated mantle-cell lymphoma (MCL), a population with poor prognosis. METHODS: Patients with cBTKi pretreated relapsed/refractory (R/R) MCL received pirtobrutinib monotherapy in a multicenter phase I/II trial (BRUIN; ClinicalTrials.gov identifier: NCT03740529). Efficacy was assessed in the first 90 consecutively enrolled patients who met criteria for inclusion in the primary efficacy cohort. The primary end point was overall response rate (ORR). Secondary end points included duration of response (DOR) and safety. RESULTS: The median patient age was 70 years (range, 46-87), the median prior lines of therapy was 3 (range, 1-8), 82.2% had discontinued a prior cBTKi because of disease progression, and 77.8% had intermediate- or high-risk simplified MCL International Prognostic Index score. The ORR was 57.8% (95% CI, 46.9 to 68.1), including 20.0% complete responses (n = 18). At a median follow-up of 12 months, the median DOR was 21.6 months (95% CI, 7.5 to not reached). The 6- and 12-month estimated DOR rates were 73.6% and 57.1%, respectively. In the MCL safety cohort (n = 164), the most common treatment-emergent adverse events (TEAEs) were fatigue (29.9%), diarrhea (21.3%), and dyspnea (16.5%). Grade ≥3 TEAEs of hemorrhage (3.7%) and atrial fibrillation/flutter (1.2%) were less common. Only 3% of patients discontinued pirtobrutinib because of a treatment-related adverse event. CONCLUSION: Pirtobrutinib is a first-in-class novel noncovalent (reversible) BTKi and the first BTKi of any kind to demonstrate durable efficacy after prior cBTKi therapy in heavily pretreated R/R MCL. Pirtobrutinib was well tolerated with low rates of treatment discontinuation because of toxicity.

Mechanisms of Resistance to Noncovalent Bruton's Tyrosine Kinase Inhibitors.

BACKGROUND: Covalent (irreversible) Bruton's tyrosine kinase (BTK) inhibitors have transformed the treatment of multiple B-cell cancers, especially chronic lymphocytic leukemia (CLL). However, resistance can arise through multiple mechanisms, including acquired mutations in BTK at residue C481, the binding site of covalent BTK inhibitors. Noncovalent (reversible) BTK inhibitors overcome this mechanism and other sources of resistance, but the mechanisms of resistance to these therapies are currently not well understood. METHODS: We performed genomic analyses of pretreatment specimens as well as specimens obtained at the time of disease progression from patients with CLL who had been treated with the noncovalent BTK inhibitor pirtobrutinib. Structural modeling, BTK-binding assays, and cell-based assays were conducted to study mutations that confer resistance to noncovalent BTK inhibitors. RESULTS: Among 55 treated patients, we identified 9 patients with relapsed or refractory CLL and acquired mechanisms of genetic resistance to pirtobrutinib. We found mutations (V416L, A428D, M437R, T474I, and L528W) that were clustered in the kinase domain of BTK and that conferred resistance to both noncovalent BTK inhibitors and certain covalent BTK inhibitors. Mutations in BTK or phospholipase C gamma 2 (PLCγ2), a signaling molecule and downstream substrate of BTK, were found in all 9 patients. Transcriptional activation reflecting B-cell-receptor signaling persisted despite continued therapy with noncovalent BTK inhibitors. CONCLUSIONS: Resistance to noncovalent BTK inhibitors arose through on-target BTK mutations and downstream PLCγ2 mutations that allowed escape from BTK inhibition. A proportion of these mutations also conferred resistance across clinically approved covalent BTK inhibitors. These data suggested new mechanisms of genomic escape from established covalent and novel noncovalent BTK inhibitors. (Funded by the American Society of Hematology and others.).

Pirtobrutinib in relapsed or refractory B-cell malignancies (BRUIN): a phase 1/2 study.

BACKGROUND: Covalent Bruton's tyrosine kinase (BTK) inhibitors are efficacious in multiple B-cell malignancies, but patients discontinue these agents due to resistance and intolerance. We evaluated the safety and efficacy of pirtobrutinib (working name; formerly known as LOXO-305), a highly selective, reversible BTK inhibitor, in these patients. METHODS: Patients with previously treated B-cell malignancies were enrolled in a first-in-human, multicentre, open-label, phase 1/2 trial of the BTK inhibitor pirtobrutinib. The primary endpoint was the maximum tolerated dose (phase 1) and overall response rate (ORR; phase 2). This trial is registered with ClinicalTrials.gov, NCT03740529. FINDINGS: 323 patients were treated with pirtobrutinib across seven dose levels (25 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, and 300 mg once per day) with linear dose-proportional exposures. No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. The recommended phase 2 dose was 200 mg daily. Adverse events in at least 10% of 323 patients were fatigue (65 [20%]), diarrhoea (55 [17%]), and contusion (42 [13%]). The most common adverse event of grade 3 or higher was neutropenia (32 [10%]). There was no correlation between pirtobrutinib exposure and the frequency of grade 3 treatment-related adverse events. Grade 3 atrial fibrillation or flutter was not observed, and grade 3 haemorrhage was observed in one patient in the setting of mechanical trauma. Five (1%) patients discontinued treatment due to a treatment-related adverse event. In 121 efficacy evaluable patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) treated with a previous covalent BTK inhibitor (median previous lines of treatment 4), the ORR with pirtobrutinib was 62% (95% CI 53-71). The ORR was similar in CLL patients with previous covalent BTK inhibitor resistance (53 [67%] of 79), covalent BTK inhibitor intolerance (22 [52%] of 42), BTK C481-mutant (17 [71%] of 24) and BTK wild-type (43 [66%] of 65) disease. In 52 efficacy evaluable patients with mantle cell lymphoma (MCL) previously treated with covalent BTK inhibitors, the ORR was 52% (95% CI 38-66). Of 117 patients with CLL, SLL, or MCL who responded, all but eight remain progression-free to date. INTERPRETATION: Pirtobrutinib was safe and active in multiple B-cell malignancies, including patients previously treated with covalent BTK inhibitors. Pirtobrutinib might address a growing unmet need for alternative therapies for these patients. FUNDING: Loxo Oncology.

Factors Associated With Complete Remission After Rituximab Therapy for Pemphigus.

Importance: Rituximab has emerged as a front-line therapy for pemphigus, but prognostic factors for achieving complete remission off therapy (CROT) with oral systemic agents remain unknown. Objectives: To describe rates of CROT and relapse and identify prognostic factors for achieving CROT after rituximab therapy for pemphigus. Design, Setting, and Participants: A single-center, retrospective, cohort study was conducted at the University of Pennsylvania including 112 patients with pemphigus treated with rituximab with at least 12 months' clinical follow-up after the start of rituximab therapy. Multivariate regression analysis of factors predictive of CROT and Kaplan-Meier analysis of disease relapse were conducted. The study included patients treated with rituximab from March 15, 2005, until December 19, 2016. Data analysis was performed from December 2017 to June 2018. Main Outcomes and Measures: The primary study outcome was CROT after 1 cycle. Secondary study outcomes included rate of CROT or the composite end point of CROT or complete remission on minimal therapy after 1 or more cycle, and median time to relapse. Multivariate regression analysis for prognostic variables for CROT, including age, sex, pemphigus subtype, body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared), disease duration, and dosing regimen, was performed. Results: A total of 112 patients with pemphigus with median 37.8 months (range, 12.1-130.7) follow-up after rituximab therapy were identified. Of these, 65 were women (58.0%). At the time of first rituximab infusion, median age was 52.3 years (range, 20.0-89.3). Including patients who received multiple cycles of rituximab, 79 patients (70.5%) achieved CROT after a median time of 10.5 months (range, 2.0-49.8), and 36 of 72 patients (50.0%) subsequently experienced relapse after a median of 23.3 months (interquartile range, 10.8-50.4 months). Considering only the first cycle of rituximab, 54 patients (48.2%) achieved CROT. Controlling for age, sex, pemphigus subtype, BMI, and disease duration, patients who received lymphoma vs rheumatoid arthritis dosing were 2.70-fold more likely to achieve CROT (odds ratio [OR], 2.70; 95% CI, 1.03-7.12; P = .04). Increasing age was associated with significant increases in achieving CROT (Wald test for trend, P = .01), whereas BMI greater than or equal to 35 was associated with a 0.14 OR (95% CI, 0.03-0.63; P = .01) for achieving CROT, regardless of the dosing regimen. In multivariate analysis, there was no significant difference in CROT rates with sex (OR, 1.01; 95% CI, 0.42-2.50; P = .97), pemphigus subtype (OR, 0.37; 95% CI, 0.09-1.51; P = .17), or disease duration (OR, 0.99; 95% CI, 0.98-1.00; P = .09). Conclusions and Relevance: Lymphoma dosing and older age may be associated with CROT and BMI greater than or equal to 35 may be a negative prognostic factor for CROT after rituximab therapy for pemphigus. These findings help inform clinical expectations and merit evaluation in future prospective clinical trials.

The changing face of adult posttransplant lymphoproliferative disorder: Changes in histology between 1999 and 2013.

Posttransplant lymphoproliferative disorder (PTLD) typically presents with either polymorphic or monomorphic histology. While both are the end result of immunosuppressive therapies, their origins are felt to be different with different prognoses and responsiveness to therapy, resulting in 2 different malignancies. We attempted to confirm reports suggesting that the relative frequency of these 2 histologies is shifting over time. We analyzed 3040 adult PTLD cases in the UNOS OPTN database from 1999 to 2013. Changes in PTLD cases over time were analyzed for histology, time from transplant to diagnosis, and patient EBV serostatus. We found that the relative proportion of polymorphic versus monomorphic histology has changed with an increase in the proportion of monomorphic cases with time (1999-2003, 54.9% vs. 45.1%; 2004-2008, 58.3% vs. 41.7%; 2009-2013, 69.7% vs. 30.3%; P = <.001). The change is driven by a gradual increase in the number of monomorphic PTLD with a steady number of polymorphic PTLD. The change is most strongly seen in transplant recipients who were EBV serostatus positive at the time of transplant. Potential causes are changes in immunosuppressive regimens with increased tacrolimus use (P = .009) and increased survival among transplant patients leading to later occurrence of PTLD (P = .001) that have occurred during the time frame analyzed. As organ transplantation has evolved over time, PTLD has coevolved. These changes in histology have important implications regarding the origin and clinical management of PTLD.

Posttransplant Lymphoproliferative Disorder in Solid Organ and Hematopoietic Stem Cell Transplantation.

Posttransplant lymphoproliferative disorders (PTLD) represent an immunosuppression-related lymphoid or plasmacytic proliferation that occur in the setting of solid organ transplant or allogeneic hematopoietic stem cell transplantation (HSCT). PTLD is a devastating consequence of HSCT and solid organ transplantation with a high morbidity and mortality. Most commonly, PTLD is related to Epstein-Barr virus (EBV) infection, but an increasing number of non-EBV-related cases are occurring. Initial therapy involves withdrawal of immunosuppression with or without antibody or cytotoxic chemotherapy. Novel therapeutic approaches including EBV-specific cytotoxic T lymphocytes are currently being studied.

Primary diffuse large B-cell lymphoma of the CNS: a rare case of spontaneous remission.

There is no consensus on the optimal therapy for primary CNS lymphoma. Conventional treatment modalities include chemotherapy and radiation therapy, which carry significant risks of morbidity and mortality. In systemic lymphomas, there are situations where non-Hodgkin lymphomas have resolved spontaneously. We now report the case of a nonimmunocompromised patient with primary CNS lymphoma who underwent a spontaneous remission with a durable response. This case suggests that not all patients with primary CNS lymphomas require aggressive treatment with chemotherapy and radiation therapy.

Long-term outcomes of rituximab, temozolomide and high-dose methotrexate without consolidation therapy for lymphoma involving the CNS.

AIM: To describe the long-term outcomes of patients with lymphoma in the CNS treated with rituximab, temozolomide and high-dose methotrexate without consolidation therapy. PATIENTS & METHODS: A retrospective cohort study of 46 consecutive patients with primary CNS lymphoma (PCNSL, 27 patients) or secondary CNS involvement of diffuse large B-cell lymphoma (DLBCL, 19 patients) who were treated with rituximab on day 1 in combination with high-dose methotrexate (days 1 and 15) and temozolomide (days 1-5) in 28-day cycles without further consolidation. RESULTS: Median follow-up was 21.2 months. Patients received a median of five cycles (range 1-15). Median overall survival (OS) was 26 months and median progression-free survival was 8.6 months. At 3 years, 37% of patients were alive and without evidence of disease. The patients with PCNSL had a significantly higher response rates (ORR 81 vs 47%; p = 0.015) and longer median OS (55.3 vs 4.8 months; p < 0.01) than those with secondary CNS DLBCL. Toxicities were mild and manageable. CONCLUSION: The rituximab, temozolomide and methotrexate regimen is an effective therapy for patients with PCNSL without the toxicities typically associated with consolidation therapy.

Outpatient Autologous Stem Cell Transplantation for Patients With Myeloma.

BACKGROUND: High-dose melphalan with autologous stem cell support improves survival for patients with myeloma. For selected patients, we have been using a protocol of short hospitalization, discharging patients to home with careful outpatient monitoring in the office, which we hypothesized would reduce complications and utilization of inpatient beds. METHODS: We reviewed 301 initial autologous transplants for myeloma, categorized as brief stay (≤ 4 days, 82 patients) or prolonged stay (≥ 5 days, 219 patients). Selection for a brief stay was determined by clinical characteristics, availability of caregivers at home, distance from our medical center, and patient preference. RESULTS: Within the brief stay population, 67% required readmission before day + 100, but this group still had fewer cumulative hospital days (9 vs. 18, P < .0001). There were fewer documented infections among brief stay patients (22% vs. 46% P < .001) and fewer admissions to intensive care units (0% vs. 5.9%, P = .02). The groups had similar rates of bleeding (1.2% vs. 1.4% P = 1.0) and thrombosis (3.7% vs. 4.6% P = 1.0). No patients in the brief stay group died within 100 days, compared with mortality of 1.8% (P = .6) in the prolonged stay group. CONCLUSION: Carefully selected patients receiving an autologous stem cell transplant for treatment of myeloma can be managed with a brief initial hospitalization and outpatient follow-up, with low morbidity and mortality.

Subcutaneous veltuzumab, a humanized anti-CD20 antibody, in the treatment of refractory pemphigus vulgaris.

IMPORTANCE B-cell depletion with the anti-CD20 antibody rituximab is highly effective for pemphigus vulgaris (PV) treatment. However,most patients experience relapse, and intravenous rituximab infusions are expensive. Therefore, cost-effective anti-CD20 therapies are desirable.OBSERVATIONS A compassionate-use investigational new drug protocol was approved to administer veltuzumab, a second-generation humanized anti-CD20 antibody, to a patient with refractory PV. Veltuzumab was administered as two 320-mg (188mg/m2) subcutaneous doses 2 weeks apart, resulting in complete remission of disease off therapy. The disease relapsed 2 years after treatment. A second cycle of subcutaneous veltuzumab, using the same dosage regimen, again induced complete remission off therapy, which remained at9 months. No serious adverse events occurred during 35 months of follow-up. Serum veltuzumab levels were 22 and 29 µg/mL 2 weeks after the first dose of each cycle, and the drug remained detectable in the serum for longer than 3 months. Relapse and response to veltuzumab generally correlated with desmoglein 3 enzyme-linked immunosorbent assay index values. Shortly after a relapse that occurred after a long-term remission, the patient demonstrated an elevated naive (CD19+CD27−) to memory (CD19+CD27+) B-cell ratio of 19.5 and transitional (CD19+CD24+CD38+) B-cell frequency of 12.5%.CONCLUSIONS AND RELEVANCE Subcutaneous veltuzumab may be a safe, effective, and more economical alternative to intravenous rituximab for PV therapy. Clinical trials of subcutaneous veltuzumab for PV are warranted.

Progressive multifocal leukoencephalopathy associated with brentuximab vedotin therapy: a report of 5 cases from the Southern Network on Adverse Reactions (SONAR) project.

BACKGROUND: Brentuximab vedotin (BV) is an anti-CD30 monoclonal antibody-drug conjugate that was approved in 2011 for the treatment of patients with anaplastic large cell and Hodgkin lymphomas. The product label indicates that 3 patients who were treated with BV developed progressive multifocal leukoencephalopathy (PML), a frequently fatal JC virus-induced central nervous system infection. Prior immunosuppressive therapy and compromised immune systems were postulated risk factors. In the current study, the authors reported 5 patients who developed BV-associated PML, including 2 immunocompetent patients. METHODS: Case information was obtained from clinicians (4 patients) or a US Food and Drug Administration database (1 patient). RESULTS: All 5 patients had lymphoid malignancies. Two patients with cutaneous T-cell lymphomas had not previously received chemotherapy. PML developed after a median of 3 BV doses (range, 2 doses-6 doses) and within a median of 7 weeks after BV initiation (range, 3 weeks-34 weeks). Presenting findings included aphasia, dysarthria, confusion, hemiparesis, and gait dysfunction; JC virus in the cerebrospinal fluid (2 patients) or central nervous system biopsy (3 patients); and brain magnetic resonance imaging scans with white matter abnormalities (5 patients). Four patients died at a median of 8 weeks (range, 6 weeks-16 weeks) after PML diagnosis. The sole survivor developed immune reconstitution inflammatory syndrome. CONCLUSIONS: PML can develop after a few BV doses and within weeks of BV initiation. Clinicians should be aware of this syndrome, particularly when neurologic changes develop after the initiation of BV treatment. The decision to administer BV to patients with indolent cutaneous lymphomas should be based on consideration of risk-benefit profiles and of alternative options.

Receipt of maintenance therapy is most predictive of survival in older acute lymphoblastic leukemia patients treated with intensive induction chemotherapy regimens.

While the prognosis for older adults diagnosed with acute lymphoblastic leukemia (ALL) is frequently poor, long-term survival can be achieved in patients treated with curative intent. We reviewed the outcomes of 37 patients age ≥60 treated at our institution with either DVP- or hyperCVAD-based chemotherapy regimens from 2003-2011. In this patient population, a complete response rate of 92%, relapse rate of 56% and median overall survival of 18.1 months was experienced. Univariate analysis revealed that receipt of maintenance therapy vs. no maintenance therapy was associated with a statistically-significant impact on overall survival (p = 0.001, HR 0.15 for death), while disease-related characteristics including high-risk white blood cell count at diagnosis and Philadelphia chromosome status as well as treatment-related factors including chemotherapy regimen or completion of intensive therapy were not. Many patients were unable to initiate or remain on maintenance therapy due to toxicities including infections and cytopenias. Our analysis reveals the benefit of prolonged therapy in the treatment of older adults with ALL as well as the high incidence of treatment-related toxicity experienced by these patients.

Plasmacytic post-transplant lymphoproliferative disorder: a case series of nine patients.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation. Although PTLD typically has a B-cell histology, an uncommon variant, plasmacytic PTLD can present as a monoclonal plasma cell proliferation similar to plasmacytomas seen in multiple myeloma. A retrospective analysis was performed on nine patients at our center with plasmacytic PTLD as characterized by plasmacytic histology with the presence of CD138 and lack of CD20. Of the 210 adult solid organ transplant PTLD patients diagnosed between 1988 and 2012, 9 (4%) had a histological appearance consistent with plasmacytic PTLD. The median time from transplant to diagnosis was 3.7 years (range 8 months-24 years). All patients presented with extranodal and often subcutaneous solid tumors. Laboratory features included elevated LDH and beta-2 microglobulin levels, monoclonal gammopathy, and EBV positivity of the tumor. Unlike conventional multiple myeloma, patients had normal calcium levels and only mild anemia. Six patients who have completed treatment achieved complete responses with radiation therapy and/or reduction in immunosuppression with two patients now greater than 5 years in continuous complete response. Plasmacytic PTLD, despite its plasmacytic histology, is responsive to conventional therapies used for B-cell PTLD including reduction in immunosuppression and radiation therapy.

Adjuvant rituximab therapy of pemphigus: a single-center experience with 31 patients.

BACKGROUND: We conducted a retrospective study of patients with pemphigus vulgaris (n = 24) and foliaceus (n = 7) treated with adjuvant rituximab to determine efficacy and adverse events. The end point for efficacy was complete remission of disease taking no or minimal therapy. OBSERVATIONS: Eighteen patients (58%) achieved the study end point. Of these, 13 patients achieved complete remission off systemic therapy. Patients achieving the study end point had a median disease duration before rituximab therapy of 19 months vs 86 months in those not achieving the end point (P = .01). For the 18 patients achieving the end point, the median (SD) duration of remission was 19 (2) months. Eight of these 18 patients (44%) relapsed from 6 to 17 months after treatment. Serious adverse events attributed to rituximab treatment (osteomyelitis or phlegmon) occurred in 2 patients (6%). In paired serum samples from 10 patients before and after rituximab treatment, the percent change in serum desmoglein index value (median, -80%) was unrelated to the percent change in pneumococcal antibodies (median, +8%) (Spearman rank correlation coefficient r = -0.2). CONCLUSIONS: Patients treated with rituximab earlier in the course of disease may have better outcomes. A discussion of rituximab's mechanism of action supports the rationale for early therapy. Prospective clinical studies are necessary to substantiate this observation.

Post-transplant lymphoproliferative disorder after lung transplantation: a review of 35 cases.

BACKGROUND: Post-transplant lymphoproliferative disorder (PTLD) is a complication of organ transplantation. The risk of developing PTLD varies depending on a number of factors, including the organ transplanted and the degree of immunosuppression used. METHODS: We report a retrospective analysis of 35 patients with PTLD treated at our center after lung transplantation. Of 705 patients who received allografts, 34 (4.8%) developed PTLD. One patient underwent transplantation elsewhere and was treated at our center. RESULTS: PTLD involved the allograft in 49% of our patients and the gastrointestinal (GI) tract lumen in 23%. Histologically, 39% of tumors were monomorphic and 48% polymorphic. The time to presentation defined the location and histology of disease. Of 17 patients diagnosed within 11 months of transplantation, PTLD involved the allograft in 12 (71%) and the GI tract in 1 (p = 0.01). This "early" PTLD was 85% polymorphic (p = 0.006). Conversely, of the 18 patients diagnosed more than 11 months after transplant, the lung was involved in 5 (28%) and the GI tract in 7 (39%; p = 0.01). "Late" PTLD was 71% monomorphic (p = 0.006). Median overall survival after diagnosis was 18.57 months. Overall survival did not differ between all lung transplant recipients and those who developed PTLD. CONCLUSIONS: PTLD is an uncommon complication after lung transplantation, and its incidence declined remarkably in the era of modern immunosuppression. We report several factors that are important for predisposition toward, progression of, and treatment of PTLD after lung transplantation.