Polatuzumab vedotin plus rituximab and lenalidomide in patients with relapsed or refractory diffuse large B-cell lymphoma: a cohort of a multicentre, single-arm, phase 1b/2 study.

BACKGROUND: Diffuse large B-cell lymphoma comprises nearly 30% of non-Hodgkin lymphoma cases and patients with relapsed or refractory diffuse large B-cell lymphoma who are ineligible for stem-cell transplantation have few treatment options and poor prognoses. We aimed to determine whether the novel combination of polatuzumab vedotin in combination with rituximab and lenalidomide (Pola+R+Len) would provide a tolerable treatment option with enhanced antitumour response in patients with relapsed or refractory diffuse large B-cell lymphoma. METHODS: This completed phase 1b/2, open-label, multicentre, single-arm study (GO29834) evaluated the safety and efficacy of Pola+R+Len in patients with relapsed or refractory diffuse large B-cell lymphoma at 19 sites in three countries (USA, Spain, and UK). Patients (≥18 years old) were eligible for inclusion if they had histologically documented CD20-positive relapsed or refractory diffuse large B-cell lymphoma and Eastern Cooperative Oncology Group performance status of 2 or lower, had received at least one previous line of chemoimmunotherapy, including an anti-CD20 agent, and were ineligible for stem-cell transplantation. The dose-escalation phase (1b) used escalating doses of lenalidomide to find the recommended phase 2 dose. Patients received six 28-day cycles of induction treatment with intravenous rituximab 375 mg/m2 and intravenous polatuzumab vedotin 1·8 mg/kg (all cohorts) plus oral lenalidomide at the following doses: 10 mg (cohort A); 15 mg (cohort B); and 20 mg (cohort C). Rituximab and polatuzumab vedotin were administered on day 1 and lenalidomide on days 1-21 of each 28-day cycle. During the dose-expansion phase (2), patients received six 28-day cycles of Pola+R+Len at the recommended phase 2 dose established during dose escalation. In both phases, patients with a complete response or partial response at the end of induction were eligible for post-induction therapy with rituximab 375 mg/m2 on day 1 and lenalidomide 10 mg/day on days 1-21 of each 28-day cycle for a maximum of 6 cycles. The primary safety objective of the dose-escalation phase was identification of the maximum tolerated dose through incidence of dose-limiting toxic effects. The primary efficacy outcome of the dose-expansion phase was Independent Review Committee-assessed complete response rate at end of induction, based on PET-CT. Analyses were conducted in the safety population, which included all patients who received at least one dose of any study drug, and the efficacy population, which included all patients who received at least one dose of any study drug at the recommended phase 2 dose. This study is registered with ClinicalTrials.gov, number NCT02600897. FINDINGS: Between July 11, 2017 and Feb 3, 2020, 57 patients were enrolled (median age 71 years [IQR 60-75]; 38 [67%] were male and 19 (33%) were female; 47 [82%] were not Hispanic or Latino; and the median previous lines of therapy was 2 [IQR 1-3]). 18 participants were included in phase 1b and 39 were included in phase 2. Phase 1b confirmed a 20 mg recommended phase 2 dose for lenalidomide. After a median follow-up of 11·8 months (IQR 4·7-25·8), the complete response rate, as assessed by the Independent Review Committee, was 31% (90% CI 20-43). The most common grade 3-4 adverse events were neutropenia (35 [61%] of 57) and thrombocytopenia (eight [14%] of 57). Serious adverse events were reported in 23 (40%) of 57 patients and one patient died due to a treatment-related adverse event (neutropenic sepsis). INTERPRETATION: Although the combination of Pola+R+Len did not meet the prespecified activity threshold, some patients derived clinical benefit and the regimen had a tolerable safety profile in patients with relapsed or refractory diffuse large B-cell lymphoma. FUNDING: Genentech/F Hoffmann-La Roche.

The COVID-19 Pandemic and In-Person Visit Rate Disruptions Among Patients With Hematologic Neoplasms in the US in 2020 to 2021.

Importance: The COVID-19 pandemic has led to a reduction in routine in-person medical care; however, it is unknown whether there have been any changes in visit rates among patients with hematologic neoplasms. Objective: To examine associations between the COVID-19 pandemic and in-person visits and telemedicine use among patients undergoing active treatment for hematologic neoplasms. Design, Setting, and Participants: Data for this retrospective observational cohort study were obtained from a nationwide electronic health record-derived, deidentified database. Data for patients with hematologic neoplasms who had received at least 1 systemic line of therapy between March 1, 2016, and February 28, 2021, were included. Treatments were categorized into 3 types: oral therapy, outpatient infusions, and inpatient infusions. The data cutoff date was April 30, 2021, when study analyses were conducted. Main Outcomes and Measures: Monthly visit rates were calculated as the number of documented visits (telemedicine or in-person) per active patient per 30-day period. We used time-series forecasting methods on prepandemic data (March 2016 to February 2020) to estimate expected rates between March 1, 2020, and February 28, 2021 (if the pandemic had not occurred). Results: This study included data for 24 261 patients, with a median age of 68 years (IQR, 60-75 years). A total of 6737 patients received oral therapy, 15 314 received outpatient infusions, and 8316 received inpatient infusions. More than half of patients were men (14 370 [58%]) and non-Hispanic White (16 309 [66%]). Early pandemic months (March to May 2020) demonstrated a significant 21% reduction (95% prediction interval [PI], 12%-27%) in in-person visit rates averaged across oral therapy and outpatient infusions. Reductions in in-person visit rates were also significant for all treatment types for multiple myeloma (oral therapy: 29% reduction; 95% PI, 21%-36%; P = .001; outpatient infusions: 11% reduction; 95% PI, 4%-17%; P = .002; inpatient infusions: 55% reduction; 95% PI, 27%-67%; P = .005), for oral therapy for chronic lymphocytic leukemia (28% reduction; 95% PI, 12%-39%; P = .003), and for outpatient infusions for mantle cell lymphoma (38% reduction; 95% PI, 6%-54%; P = .003) and chronic lymphocytic leukemia (20% reduction; 95% PI, 6%-31%; P = .002). Telemedicine visit rates were highest for patients receiving oral therapy, with greater use in the early pandemic months and a subsequent decrease in later months. Conclusions and Relevance: In this cohort study of patients with hematologic neoplasms, documented in-person visit rates for those receiving oral therapy and outpatient infusions significantly decreased during the early pandemic months but returned to close to projected rates in the later half of 2020. There were no statistically significant reductions in the overall in-person visit rate for patients receiving inpatient infusions. There was higher telemedicine use in the early pandemic months, followed by a decline, but use was persistent in the later half of 2020. Further studies are needed to ascertain associations between the COVID-19 pandemic and subsequent cancer outcomes and the evolution of telemedicine use for care delivery.

The DISCO App: A pilot test of a multi-level intervention to reduce the financial burden of cancer through improved cost communication.

Objective: Financial toxicity affects 30-50% of people with cancer in the US. Although experts recommend patients and physicians discuss treatment cost, cost discussions occur infrequently. We pilot-tested the feasibility, acceptability and influence on outcomes of the DIScussions of COst (DISCO) App, a multi-level communication intervention designed to improve cost discussions and related outcomes. Methods: While waiting to see their physician, patients (n = 32) used the DISCO App on a tablet. Physicians were given a cost discussion tip sheet. Clinic visits were video recorded and patients completed pre- and post-intervention measures of self-efficacy for managing costs, self-efficacy for interacting with physicians, cost-related distress, and perceptions of the DISCO App. Coders observed the recordings to determine the presence of cost discussions, initiators, and topics. Results: Most patients reported needing ≤15 min to use the DISCO App, and that it made it easier to ask cost-related questions. Findings showed increased self-efficacy for managing treatment costs (p = .02) and for interacting with physicians (p = .001). All visits included a cost discussion. Conclusions: Prompting patients to discuss costs may improve cost treatment discussions and related outcomes. Innovation: An app-based and tailorable treatment-cost communication intervention is feasible, acceptable, and demonstrates promise in prompting cost discussions and improving outcomes.Trial registration: Clinical Trials.gov registration number: NCT03676920 (September 19, 2018).

How to Effectively Decrease Patient Co-Payments of High-Cost Drugs Through Innovation: Lessons From the Karmanos Specialty Pharmacy.

PURPOSE: High-cost drugs impose a financial burden on patients with cancer. Karmanos Specialty Pharmacy (KSP) developed a process to automate financial assistance (FA) applications to decrease patient drug cost. We evaluate the outcomes of this program on cost to patients and payers. METHODS: This is an observational, retrospective study of the KSP claims data set from January to December 2019, accessed by 13 statewide cancer centers within Michigan. Drug cost of patients, payers, FA (funds to lower patient drug cost), and types of FA were obtained. A subset analysis was performed to determine drug delivery times. RESULTS: In 2019, 869 prescriptions and 1,722 prescription fills were provided to 463 patients through KSP. The total cost of drug claims was approximately $10 million US dollars (USD) among Medicare patients (58%), approximately $3.4 million USD for privately insured patients (20%), and approximately $3.7 million USD for Medicaid patients (22%). Twenty-seven percent of patients (22% of all prescription fills) required additional FA with initial total co-payment claims of $335,216 USD. $280,988 USD of FA was obtained, which substantially lowered total patient costs by 81%. $250,818 USD of FA obtained was from foundation grants (327 fills), and $21,441 USD from manufacturer co-pay cards (47 fills). An additional $12,260 USD (12 fills) from a Karmanos Patient Assistance Fund was used. There was high dependence on foundation grant assistance among Medicare patients (33% of claims). In a subset analysis, the median time from prescription written to delivery to the patient was < 7 days (0-56 days). CONCLUSION: Twenty-seven percent of patients (22% of prescriptions fills) in 2019 required additional FA for high-cost drugs. KSP substantially reduced patient cost by implementing an efficient process using additional pharmacy assistants to obtain FA.

Selinexor in Combination with R-CHOP for Frontline Treatment of Non-Hodgkin Lymphoma: Results of a Phase I Study.

PURPOSE: The nuclear exporter protein exportin-1 (XPO1) is overexpressed in non-Hodgkin lymphoma (NHL) and correlates with poor prognosis. We evaluated enhancing R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) activity in NHL by targeted inhibition of XPO1 using the selective inhibitor of nuclear export (SINE) compounds. PATIENTS AND METHODS: We evaluated the antitumor activity of SINE compounds in combination with CHO chemotherapy in vitro and in vivo. Newly diagnosed NHL patients in a phase I dose-escalation study received R-CHOP for 6 cycles with weekly selinexor (60, 80, and 100 mg), then selinexor maintenance therapy for one year. RT-PCR, Western blotting, and RNA sequencing were performed on patient blood samples. RESULTS: SINE compounds synergized with CHO in vitro in NHL cell lines and in vivo in our murine xenograft model. In our phase I study, selinexor was dosed at 60 mg (n = 6) and 80 mg (n = 6). The most common adverse events (AE) among 12 patients were fatigue (67%) and nausea (100%). Grade 3-4 AEs were infrequent. Ten evaluable patients had an overall response rate of 100% and complete remission rate of 90% with sustained remissions (median follow-up: 476 days). Maximally tolerated dose was not reached; however, the recommended phase II dose was 60 mg selinexor weekly after evaluating tolerability and discontinuation rates for each dose cohort. Analysis of patient blood samples revealed downregulation of XPO1 and several prosurvival markers. CONCLUSIONS: SINE compounds enhance the activity of CHO in vitro and in vivo. Selinexor in combination with R-CHOP was generally well tolerated and showed encouraging efficacy in NHL (NCT03147885).

The costs of treating and not treating patients with chronic myeloid leukemia with tyrosine kinase inhibitors among Medicare patients in the United States.

BACKGROUND: Patients with high cost-sharing of tyrosine kinase inhibitors (TKIs) experience delays in treatment for chronic myeloid leukemia (CML). To the authors' knowledge, the clinical outcomes among and costs for patients not receiving TKIs are not well defined. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, the authors evaluated differences in TKI initiation, health care use, cost, and survival among patients with CML with continuous Medicare Parts A and B and Part D coverage who were diagnosed between 2007 and 2015. RESULTS: A total of 941 patients were included. Approximately 29% of all patients did not initiate treatment with TKIs within 6 months (non-TKI users), and had lower rates of BCR-ABL testing and more hospitalizations compared with TKI users. Approximately 21% were not found to have any TKI claims at any time. TKI initiation rates within 6 months of diagnosis increased for all patients over time (61% to 85%), with greater improvements observed in patients receiving subsidies (55% to 90%). Total Medicare costs were greater in patients treated with TKIs, with approximately 50% because of TKI costs. Non-TKI users had more inpatient costs compared with TKI users. Trends in cost remained significant when adjusting for age and comorbidities. The median overall survival was 40 months (95% confidence interval [95% CI], 34-48 months) compared with 86 months (95% CI, 73 months to not reached), respectively, for non-TKI users versus TKI users, a finding that remained consistent when adjusting for age, comorbidities, and subsidy status (hazard ratio, 2.23; 95% CI, 1.77-2.81). CONCLUSIONS: Approximately 21% of all patients with CML did not receive TKIs at any time. Cost-sharing subsidies consistently are found to be associated with higher initiation rates. Non-TKI users had higher inpatient costs and poorer survival outcomes. Interventions to lower TKI costs for all patients are desirable.

Incorporating Value-Based Care Into Oncology.

Value-based care within insurance design utilizes evidence-based medicine as a means of defining high-value versus low-value diagnostics and treatments. The goals of value-based care are to shift spending and coverage toward high-value care and reduce the use of low-value practices. Within oncology, several value-based methods have been proposed and implemented. We review value-based care being used within oncology, including defining the value of oncology drugs through frameworks, clinical care pathways, alternative payment models including the Oncology Care Model, value-based insurance design, and reducing low-value care including the Choosing Wisely initiatives.

Outcomes of COVID-19 in patients with CLL: a multicenter international experience.

Given advanced age, comorbidities, and immune dysfunction, chronic lymphocytic leukemia (CLL) patients may be at particularly high risk of infection and poor outcomes related to coronavirus disease 2019 (COVID-19). Robust analysis of outcomes for CLL patients, particularly examining effects of baseline characteristics and CLL-directed therapy, is critical to optimally manage CLL patients through this evolving pandemic. CLL patients diagnosed with symptomatic COVID-19 across 43 international centers (n = 198) were included. Hospital admission occurred in 90%. Median age at COVID-19 diagnosis was 70.5 years. Median Cumulative Illness Rating Scale score was 8 (range, 4-32). Thirty-nine percent were treatment naive ("watch and wait"), while 61% had received ≥1 CLL-directed therapy (median, 2; range, 1-8). Ninety patients (45%) were receiving active CLL therapy at COVID-19 diagnosis, most commonly Bruton tyrosine kinase inhibitors (BTKi's; n = 68/90 [76%]). At a median follow-up of 16 days, the overall case fatality rate was 33%, though 25% remain admitted. Watch-and-wait and treated cohorts had similar rates of admission (89% vs 90%), intensive care unit admission (35% vs 36%), intubation (33% vs 25%), and mortality (37% vs 32%). CLL-directed treatment with BTKi's at COVID-19 diagnosis did not impact survival (case fatality rate, 34% vs 35%), though the BTKi was held during the COVID-19 course for most patients. These data suggest that the subgroup of CLL patients admitted with COVID-19, regardless of disease phase or treatment status, are at high risk of death. Future epidemiologic studies are needed to assess severe acute respiratory syndrome coronavirus 2 infection risk, these data should be validated independently, and randomized studies of BTKi's in COVID-19 are needed to provide definitive evidence of benefit.

Increasing incidence of Epstein-Barr virus-related nasopharyngeal carcinoma in the United States.

BACKGROUND: The incidence of nasopharyngeal carcinoma (NPC) has been historically low in the United States. Although etiological factors differ by histological subtype, Epstein-Barr virus is accepted as the primary risk factor for nonkeratinizing NPC. In light of the changing epidemiology of viral-associated cancers, it is important to evaluate the temporal incidence of NPC in the United States. METHODS: Incidence and survival data from 1973 through 2015 were obtained from the Surveillance, Epidemiology, and End Results program. Stratified analyses were conducted to assess temporal trends in NPC by histological subtype, sex, and race. The data were analyzed using SAS and Joinpoint Regression Software to determine age-adjusted incidence rates, determine trends in the annual percent change, and calculate 5-year relative survival estimates and Kaplan-Meier curves. RESULTS: Although overall NPC incidence is decreasing in the United States, the nonkeratinizing differentiated subtype is starkly increasing, with an annual percent change of approximately 4% among white males (95% CI, 2.5%-5.2%), white females (95% CI, 1.9%-6.2%), and black males (95% CI, 2.0%, 5.7%); 2.7% among black females (95% CI, 0.8%, 4.6%); and 1.8% among women in the "other" race category (95% CI, 0.4%-3.3%). Racial disparities were noted, with 32% of nonkeratinizing NPC cases among blacks occurring before the age of 40 years. In addition, black males displayed consistently worse survival across all histological subtypes, whereas individuals in the "other" race category, particularly females, experienced the highest 5-year relative survival estimates. CONCLUSIONS: The current results indicate that the Epstein-Barr virus-related, differentiated NPC subtype is increasing across all sexes and races in the United States, with distinct incidence and survival disparities among blacks.

Real-world testing and treatment patterns in chronic lymphocytic leukemia: A SEER patterns of care analysis.

BACKGROUND: Laboratory testing and treatments for chronic lymphocytic leukemia (CLL) have changed dramatically within the last decade. The authors evaluated changes in patterns of real-world testing and treatment over time by comparing 2 population-based cohorts. METHODS: The National Cancer Institute-sponsored Patterns of Care study was conducted among patients with CLL who were sampled from 14 Surveillance, Epidemiology, and End Results (SEER) program registries. Demographics, testing, and treatment data were abstracted from medical records within 24 months of diagnosis. RESULTS: A total of 1008 patients diagnosed in 2008 and 1367 patients diagnosed in 2014 were included. There was a significant increase in fluorescence in situ hybridization (FISH) testing, immunoglobulin heavy-chain variable region gene (IgVH ) mutation analyses, and lymph node biopsies between 2008 and 2014. FISH testing was performed in the majority of, but not all, treated patients (53% in 2008, which increased to 62% in 2014). Some differences in the receipt of FISH testing by age and insurance status were observed over time (older patients and Medicare patients without private insurance were less likely to be tested in 2014). There were contrasting testing patterns noted by practice type and year, with nonteaching hospitals more likely to perform bone marrow biopsies in 2008, and teaching hospitals more likely to perform FISH and IgVH testing in 2014. There also were differences in treatments over time, with the use of bendamustine and rituximab being more common in 2014, at the expense of fludarabine, cyclophosphamide, and rituximab. CONCLUSIONS: There have been rapidly changing practices in the testing and treatment patterns of patients with CLL within the last decade.

Challenges in the Clinical Application of the American Society of Clinical Oncology Value Framework: A Medicare Cost-Benefit Analysis in Chronic Lymphocytic Leukemia.

PURPOSE: The ASCO Value Framework calculates the value of cancer therapies. Given costly novel therapeutics for chronic lymphocytic leukemia, we used the framework to compare net health benefit (NHB) and cost within Medicare of all regimens listed in the National Comprehensive Cancer Network (NCCN) guidelines. METHODS: The current NCCN guidelines for chronic lymphocytic leukemia were reviewed. All referenced studies were screened, and only randomized controlled prospective trials were included. The revised ASCO Value Framework was used to calculate NHB. Medicare drug pricing was used to calculate the cost of therapies. RESULTS: Forty-nine studies were screened. The following observations were made: only 10 studies (20%) could be evaluated; when comparing regimens studied against the same control arm, ranking NHB scores were comparable to their preference in guidelines; NHB scores varied depending on which variables were used, and there were no clinically validated thresholds for low or high values; treatment-related deaths were not weighted in the toxicity scores; and six of the 10 studies used less potent control arms, ranked as the least-preferred NCCN-recommended regimens. CONCLUSION: The ASCO Value Framework is an important initial step to quantify value of therapies. Essential limitations include the lack of clinically relevant validated thresholds for NHB scores and lack of incorporation of grade 5 toxicities/treatment-related mortality into its methodology. To optimize its application for clinical practice, we urge investigators/sponsors to incorporate and report the required variables to calculate the NHB of regimens and encourage trials with stronger comparator arms to properly quantify the relative value of therapies.

Colony-Stimulating Factor-1 Receptor Is Required for Nurse-like Cell Survival in Chronic Lymphocytic Leukemia.

PURPOSE: Monocytes and their progeny are abundant constituents of the tumor microenvironment in lymphoproliferative disorders, including chronic lymphocytic leukemia (CLL). Monocyte-derived cells, including nurse-like cells (NLC) in CLL, promote lymphocyte proliferation and survival, confer resistance to chemotherapy, and are associated with more rapid disease progression. Colony-stimulating factor-1 receptor (CSF-1R) regulates the homeostatic survival of tissue-resident macrophages. Therefore, we sought to determine whether CSF-1R is similarly required for NLC survival. EXPERIMENTAL DESIGN: CSF-1R expression by NLC was examined by flow cytometry and IHC. CSF-1R blocking studies were performed using an antagonistic mAb to examine its role in NLC generation and in CLL survival. A rational search strategy was performed to identify a novel tyrosine kinase inhibitor (TKI) targeting CSF-1R. The influence of TKI-mediated CSF-1R inhibition on NLC and CLL viability was examined. RESULTS: We demonstrated that the generation and survival of NLC in CLL is dependent upon CSF-1R signaling. CSF-1R blockade is associated with significant depletion of NLC and consequently inhibits CLL B-cell survival. We found that the JAK2/FLT3 inhibitor pacritinib suppresses CSF-1R signaling, thereby preventing the generation and survival of NLC and impairs CLL B-cell viability. CONCLUSIONS: CSF-1R is a novel therapeutic target that may be exploited in lymphoproliferative disorders, like CLL, that are dependent upon lymphoma-associated macrophages. Clin Cancer Res; 22(24); 6118-28. ©2016 AACR.

A Quantitative Analysis of Subclonal and Clonal Gene Mutations before and after Therapy in Chronic Lymphocytic Leukemia.

PURPOSE: Chronic lymphocytic leukemia (CLL)-associated gene mutations that influence CLL cell fitness and chemotherapy resistance should increase in clonal representation when measured before therapy and at relapse. EXPERIMENTAL DESIGN: To uncover mutations associated with CLL relapse, we have performed whole-exome sequencing in a discovery cohort of 61 relapsed CLL patients identifying 86 recurrently mutated genes. The variant allele fractions (VAF) of 19 genes with mutations in ≥3 of 61 cases were measured in 53 paired pre- and posttreatment CLL samples sorted to purity using panel-based deep resequencing or by droplet digital PCR. RESULTS: We identify mutations in TP53 as the dominant subclonal gene driver of relapsed CLL often demonstrating substantial increases in VAFs. Subclonal mutations in SAMHD1 also recurrently demonstrated increased VAFs at relapse. Mutations in ATP10A, FAT3, FAM50A, and MGA, although infrequent, demonstrated enrichment in ≥2 cases each. In contrast, mutations in NOTCH1, SF3B1, POT1, FBXW7, MYD88, NXF1, XPO1, ZMYM3, or CHD2 were predominantly already clonal prior to therapy indicative of a pretreatment pathogenetic driver role in CLL. Quantitative analyses of clonal dynamics uncover rising, stable, and falling clones and subclones without clear evidence that gene mutations other than in TP53 and possibly SAMHD1 are frequently selected for at CLL relapse. CONCLUSIONS: Data in aggregate support a provisional categorization of CLL-associated recurrently mutated genes into three classes (i) often subclonal before therapy and strongly enriched after therapy, or, (ii) mostly clonal before therapy or without further enrichments at relapse, or, (iii) subclonal before and after therapy and enriching only in sporadic cases. Clin Cancer Res; 22(17); 4525-35. ©2016 AACR.

Multidimensional single-cell analysis of BCR signaling reveals proximal activation defect as a hallmark of chronic lymphocytic leukemia B cells.

PURPOSE: Chronic Lymphocytic Leukemia (CLL) is defined by a perturbed B-cell receptor-mediated signaling machinery. We aimed to model differential signaling behavior between B cells from CLL and healthy individuals to pinpoint modes of dysregulation. EXPERIMENTAL DESIGN: We developed an experimental methodology combining immunophenotyping, multiplexed phosphospecific flow cytometry, and multifactorial statistical modeling. Utilizing patterns of signaling network covariance, we modeled BCR signaling in 67 CLL patients using Partial Least Squares Regression (PLSR). Results from multidimensional modeling were validated using an independent test cohort of 38 patients. RESULTS: We identified a dynamic and variable imbalance between proximal (pSYK, pBTK) and distal (pPLCγ2, pBLNK, ppERK) phosphoresponses. PLSR identified the relationship between upstream tyrosine kinase SYK and its target, PLCγ2, as maximally predictive and sufficient to distinguish CLL from healthy samples, pointing to this juncture in the signaling pathway as a hallmark of CLL B cells. Specific BCR pathway signaling signatures that correlate with the disease and its degree of aggressiveness were identified. Heterogeneity in the PLSR response variable within the B cell population is both a characteristic mark of healthy samples and predictive of disease aggressiveness. CONCLUSION: Single-cell multidimensional analysis of BCR signaling permitted focused analysis of the variability and heterogeneity of signaling behavior from patient-to-patient, and from cell-to-cell. Disruption of the pSYK/pPLCγ2 relationship is uncovered as a robust hallmark of CLL B cell signaling behavior. Together, these observations implicate novel elements of the BCR signal transduction as potential therapeutic targets.

Clonal evolution, genomic drivers, and effects of therapy in chronic lymphocytic leukemia.

PURPOSE: The identification of gene mutations and structural genomic aberrations that are critically involved in chronic lymphocytic leukemia (CLL) pathogenesis is still evolving. One may postulate that genomic driver lesions with effects on CLL cell proliferation, apoptosis thresholds, or chemotherapy resistance should increase in frequency over time when measured sequentially in a large CLL cohort. EXPERIMENTAL DESIGN: We sequentially sampled a large well-characterized CLL cohort at a mean of 4 years between samplings and measured acquired copy number aberrations (aCNA) and LOH using single-nucleotide polymorphism (SNP) 6.0 array profiling and the mutational state of TP53, NOTCH1, and SF3B1 using Sanger sequencing. The paired analysis included 156 patients, of whom 114 remained untreated and 42 received intercurrent therapies, predominantly potent chemoimmunotherapy, during the sampling interval. RESULTS: We identify a strong effect of intercurrent therapies on the frequency of acquisition of aCNAs in CLL. Importantly, the spectrum of acquired genomic changes was largely similar in patients who did or did not receive intercurrent therapies; therefore, various genomic changes that become part of the dominant clones are often already present in CLL cell populations before therapy. Furthermore, we provide evidence that therapy of CLL with preexisting TP53 mutations results in outgrowth of genomically very complex clones, which dominate at relapse. CONCLUSIONS: Using complementary technologies directed at the detection of genomic events that are present in substantial proportions of the clinically relevant CLL disease bulk, we capture aspects of genomic evolution in CLL over time, including increases in the frequency of genomic complexity, specific recurrent aCNAs, and TP53 mutations.