Ibrutinib in previously treated Waldenström's macroglobulinemia.

BACKGROUND: MYD88(L265P) and CXCR4(WHIM) mutations are highly prevalent in Waldenström's macroglobulinemia. MYD88(L265P) triggers tumor-cell growth through Bruton's tyrosine kinase, a target of ibrutinib. CXCR4(WHIM) mutations confer in vitro resistance to ibrutinib. METHODS: We performed a prospective study of ibrutinib in 63 symptomatic patients with Waldenström's macroglobulinemia who had received at least one previous treatment, and we investigated the effect of MYD88 and CXCR4 mutations on outcomes. Ibrutinib at a daily dose of 420 mg was administered orally until disease progression or the development of unacceptable toxic effects. RESULTS: After the patients received ibrutinib, median serum IgM levels decreased from 3520 mg per deciliter to 880 mg per deciliter, median hemoglobin levels increased from 10.5 g per deciliter to 13.8 g per deciliter, and bone marrow involvement decreased from 60% to 25% (P<0.01 for all comparisons). The median time to at least a minor response was 4 weeks. The overall response rate was 90.5%, and the major response rate was 73.0%; these rates were highest among patients with MYD88(L265P)CXCR4(WT) (with WT indicating wild-type) (100% overall response rate and 91.2% major response rate), followed by patients with MYD88(L265P)CXCR4(WHIM) (85.7% and 61.9%, respectively) and patients with MYD88(WT)CXCR4(WT) (71.4% and 28.6%). The estimated 2-year progression-free and overall survival rates among all patients were 69.1% and 95.2%, respectively. Treatment-related toxic effects of grade 2 or higher included neutropenia (in 22% of the patients) and thrombocytopenia (in 14%), which were more common in heavily pretreated patients; postprocedural bleeding (in 3%); epistaxis associated with the use of fish-oil supplements (in 3%); and atrial fibrillation associated with a history of arrhythmia (5%). CONCLUSIONS: Ibrutinib was highly active, associated with durable responses, and safe in pretreated patients with Waldenström's macroglobulinemia. MYD88 and CXCR4 mutation status affected responses to this drug. (Funded by Pharmacyclics and others; ClinicalTrials.gov number, NCT01614821.).

Clonal architecture of CXCR4 WHIM-like mutations in Waldenström Macroglobulinaemia.

CXCR4(WHIM) somatic mutations are distinctive to Waldenström Macroglobulinaemia (WM), and impact disease presentation and treatment outcome. The clonal architecture of CXCR4(WHIM) mutations remains to be delineated. We developed highly sensitive allele-specific polymerase chain reaction (AS-PCR) assays for detecting the most common CXCR4(WHIM) mutations (CXCR4(S338X C>A and C>G) ) in WM. The AS-PCR assays detected CXCR4(S338X) mutations in WM and IgM monoclonal gammopathy of unknown significance (MGUS) patients not revealed by Sanger sequencing. By combined AS-PCR and Sanger sequencing, CXCR4(WHIM) mutations were identified in 44/102 (43%), 21/62 (34%), 2/12 (17%) and 1/20 (5%) untreated WM, previously treated WM, IgM MGUS and marginal zone lymphoma patients, respectively, but no chronic lymphocytic leukaemia, multiple myeloma, non-IgM MGUS patients or healthy donors. Cancer cell fraction analysis in WM and IgM MGUS patients showed CXCR4(S338X) mutations were primarily subclonal, with highly variable clonal distribution (median 35·1%, range 1·2-97·5%). Combined AS-PCR and Sanger sequencing revealed multiple CXCR4(WHIM) mutations in many individual WM patients, including homozygous and compound heterozygous mutations validated by deep RNA sequencing. The findings show that CXCR4(WHIM) mutations are more common in WM than previously revealed, and are primarily subclonal, supporting their acquisition after MYD88(L265P) in WM oncogenesis. The presence of multiple CXCR4(WHIM) mutations within individual WM patients may be indicative of targeted CXCR4 genomic instability.

Carfilzomib, rituximab, and dexamethasone (CaRD) treatment offers a neuropathy-sparing approach for treating Waldenström's macroglobulinemia.

Bortezomib frequently produces severe treatment-related peripheral neuropathy (PN) in Waldenström's macroglobulinemia (WM). Carfilzomib is a neuropathy-sparing proteasome inhibitor. We examined carfilzomib, rituximab, and dexamethasone (CaRD) in symptomatic WM patients naïve to bortezomib and rituximab. Protocol therapy consisted of intravenous carfilzomib, 20 mg/m2 (cycle 1) and 36 mg/m(2) (cycles 2-6), with intravenous dexamethasone, 20 mg, on days 1, 2, 8, and 9, and rituximab, 375 mg/m(2), on days 2 and 9 every 21 days. Maintenance therapy followed 8 weeks later with intravenous carfilzomib, 36 mg/m(2), and intravenous dexamethasone, 20 mg, on days 1 and 2, and rituximab, 375 mg/m(2), on day 2 every 8 weeks for 8 cycles. Overall response rate was 87.1% (1 complete response, 10 very good partial responses, 10 partial responses, and 6 minimal responses) and was not impacted by MYD88(L265P) or CXCR4(WHIM) mutation status. With a median follow-up of 15.4 months, 20 patients remain progression free. Grade ≥2 toxicities included asymptomatic hyperlipasemia (41.9%), reversible neutropenia (12.9%), and cardiomyopathy in 1 patient (3.2%) with multiple risk factors, and PN in 1 patient (3.2%) which was grade 2. Declines in serum IgA and IgG were common. CaRD offers a neuropathy-sparing approach for proteasome inhibitor-based therapy in WM. This trial is registered at www.clinicaltrials.gov as #NCT01470196.

Incidence of secondary malignancies among patients with Waldenström macroglobulinemia: An analysis of the SEER database.

BACKGROUND: Waldenström macroglobulinemia (WM) is an indolent malignancy that predominantly affects older individuals who are at risk for secondary malignancies (SMs). The objective of this study was to characterize the incidence of SMs after a diagnosis of WM with the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: With SEER-13 data (1992-2011), standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated for the rates of solid and hematologic SMs in WM patients versus the general population. The analysis was stratified by age, sex, race, year of diagnosis, and latency from the WM diagnosis. RESULTS: Among 4676 patients with WM, 681 SMs were recorded. The overall SIR was 1.49 (95% CI, 1.38-1.61), and the median time to an SM was 3.7 years. The cumulative incidence of SMs was 10% at 5 years and 16% at 10 years. The risk was significantly increased for cancers of the lungs, urinary tract, and thyroid; melanoma; aggressive lymphoma; and acute leukemia. The SIR for SMs in patients with WM was increased, regardless of age, sex, race, or year of diagnosis. CONCLUSIONS: Patients with WM had a 49% higher risk of SMs than the general population. The selectively increased risk for hematologic SMs and certain solid SMs may be associated with transformation, therapy, and immune dysregulation.

Overall survival and competing risks of death in patients with Waldenström macroglobulinaemia: an analysis of the Surveillance, Epidemiology and End Results database.

Waldenström macroglobulinaemia (WM) is a rare and incurable lymphoma. Given that the survival of WM patients can be prolonged, our objective was to describe trends in overall survival (OS) and analyse competing risks of death in patients with WM. The analysis included 5784 patients diagnosed with WM between 1991 and 2010 from the Surveillance, Epidemiology and End Results (SEER) database. Multivariate hazard models for OS and cumulative incidence of death were fitted according to epoch of diagnosis (1991-2000 vs. 2001-10) while adjusting for age, sex, race, histology, site of involvement and registry. Median OS for the 1991-2000 and the 2001-10 cohorts was 6 and 8 years, respectively (P < 0·001). In the multivariate analysis, better OS [hazard ratio (HR) 0·73, 95% confidence interval (CI) 0·67-0·79; P < 0·001] was seen in the 2001-10 cohort. Survival benefits were identified, for the 2001-10 cohort, in almost every stratum analysed, with the exception of patients aged <50 years and blacks. In the multivariate competing-risk analysis, the 2001-10 cohort experienced lower rates of WM-related (HR 0·57, 95% CI 0·49-0·66; P < 0·001) and non-WM-related deaths (HR 0·72, 95% CI 0·66-0·79; P < 0·001). In conclusion, there have been significant improvements in OS, WM-related and non-WM-related mortality in patients with WM diagnosed in the last decade.

CXCR4 WHIM-like frameshift and nonsense mutations promote ibrutinib resistance but do not supplant MYD88(L265P) -directed survival signalling in Waldenström macroglobulinaemia cells.

CXCR4(WHIM) frameshift and nonsense mutations follow MYD88(L265P) as the most common somatic variants in Waldenström Macroglobulinaemia (WM), and impact clinical presentation and ibrutinib response. While the nonsense (CXCR4(S338X) ) mutation has been investigated, little is known about CXCR4 frameshift (CXCR4(FS) ) mutations. We engineered WM cells to express CXCR4(FS) mutations present in patients, and compared their CXCL12 (SDF-1a) induced signalling and ibrutinib sensitivity to CXCR4(wild-type (WT)) and CXCR4(S338X) cells. Following CXCL12 stimulation, CXCR4(FS) and CXCR4(S338X) WM cells showed impaired CXCR4 receptor internalization, and enhanced AKT1 (also termed AKT) and MAPK1 (also termed ERK) activation versus CXCR(WT) cells (P < 0·05), though MAPK1 activation was more prolonged in CXCR4(S338X) cells (P < 0·05). CXCR4(FS) and CXCR4(S338X) cells, but not CXCR4(WT) cells, were rescued from ibrutinib-triggered apoptosis by CXCL12 that was reversed by AKT1, MAPK1 or CXCR4 antagonists. Treatment with an inhibitor that blocks MYD88(L265P) signalling triggered similar levels of apoptosis that was not abrogated by CXCL12 treatment in CXCR4(WT) and CXCR4(WHIM) cells. These studies show a functional role for CXCR4(FS) mutations in WM, and provide a framework for the investigation of CXCR4 antagonists with ibrutinib in CXCR4(WHIM) -mutated WM patients. Direct inhibition of MYD88(L265P) signalling overcomes CXCL12 triggered survival effects in CXCR4(WHIM) -mutated cells supporting a primary role for this survival pathway in WM.

Survival outcomes of secondary cancers in patients with Waldenström macroglobulinemia: An analysis of the SEER database.

We hypothesized that survival outcomes of WM patients who develop SM is distinct from the general population of individuals who develop those same malignancies. Using the SEER-18 data (2000-2011), we identified patients with cancers of the breast, prostate, lung, colorectum, bladder, melanoma, non-Hodgkin lymphoma (NHL), and acute leukemia, and compared their outcomes according to having antecedent WM or not. The outcome of interest was overall survival (OS), which was analyzed in proportional-hazard models adjusted for age, sex, race, and stage. We found that patients with WM who developed SM were older than population controls with those same cancers. In the multivariate analysis, WM cases with colorectal cancer (HR 1.97; P < 0.001), melanoma (HR 2.63; P < 0.001) and NHL (HR = 1.35; P = 0.02) had worse OS than controls with those respective cancers. WM patients with diffuse large B-cell lymphoma also had worse OS (HR = 1.86; P = 0.008). The utilization of surgery and radiation was similar between WM cases and controls, except lower rates of prostatectomy and melanoma surgery among WM patients. The survival of WM patients with colorectal cancer, melanoma, and NHL is worse than among general population controls, arguing in favor of age-appropriate cancer screening.

Ibrutinib Monotherapy in Relapsed or Refractory, Transformed Diffuse Large B-cell Lymphoma.

BACKGROUND: Histologic transformation to diffuse large B-cell lymphoma (tDLBCL) occurs in a significant proportion of indolent lymphomas. However, few studies of novel agents inform its management, particularly when relapsed after or refractory (R/R) to prior treatment. PATIENTS AND METHODS: We prospectively evaluated ibrutinib monotherapy in pathologically documented patients with R/R tDLBCL in a single-arm study. The primary endpoint was overall response rate. RESULTS: Twenty patients who had received a median of 4 (range, 2-9) prior lines of therapy overall (median, 2.5; range, 1-9 for tDLBCL) were treated. The overall response rate was 35%, including complete responses in 15%. The median progression-free survival and overall survival were 4.1 months (95% confidence interval, 2.4-6.2 months) and 22.4 months (95% confidence interval, 7.5 months to not reached), respectively. Disease control > 2 months was seen in 75% and > 1 year in 15%. Response was associated with either low tumor bulk or low metabolic tumor volume (P = .05) but not with antecedent lymphoma histology (P = 1.0). Treatment-related adverse events were consistent with prior studies of ibrutinib. CONCLUSIONS: Ibrutinib showed low toxicity and meaningful efficacy in R/R tDLBCL, including short-term disease control in most cases. Results demonstrate the potential utility of ibrutinib in this challenging clinical setting, including as a potential bridge to more definitive treatments.

Modified VR-CAP, Alternating With Rituximab and High-dose Cytarabine: An Effective Pre-transplant Induction Regimen for Mantle Cell Lymphoma.

BACKGROUND: Initial treatment of mantle cell lymphoma (MCL) incorporating autologous stem cell transplantation affords long-term remissions, but relapses still occur. Optimal pretransplant therapy will afford high complete response rates and not impair stem cell collection. Incorporation of bortezomib represents a natural evolution of pretransplant therapy, given its proven first-line efficacy and minimal impact on stem cell collection. PATIENTS AND METHODS: At the University of Washington/Seattle Cancer Care Alliance and the Cleveland Clinic Foundation, we developed modified VR-CAP/R+ara-C (bortezomib, rituximab, cyclophosphamide, doxorubicin, and prednisone, alternating with rituximab and high-dose cytarabine), for transplant-eligible patients with MCL. This regimen was administered as standard-of-care, pretransplant therapy to consecutive patients with MCL from April 2015 to the present. RESULTS: A total of 37 patients were treated with this regimen, including 18 at the University of Washington/Seattle Cancer Care Alliance and 19 at the Cleveland Clinic Foundation. Most patients had intermediate- or high-risk disease by both (mantle-cell lymphoma international prognostic index (MIPI)-B and MIPI-C category. Complete response to induction was achieved in 32 (86%) of 37 evaluable patients; 2 achieved partial response, and 3 had primary refractory disease. Stem cell collection was successful in 1 attempt in 30 of 32 patients. The median follow-up of survivors measured from start of treatment is 17.4 months. Five patients have progressed, and 4 have died (2 owing to lymphoma, 2 from toxicity). CONCLUSION: Modified VR-CAP/R+ara-C is feasible pretransplant therapy for patients with MCL and is associated with a high rate of complete response and eligibility for autologous stem cell transplantation.

Pegylated GCSF Can Be Used With First-Line da-EPOCH-R Without Compromising Dose Intensity, Safety, or Efficacy.

INTRODUCTION: Infusional da-EPOCH-R (dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab) is a dose-intensified regimen with a potential role in treating high-risk subtypes of aggressive B-cell non-Hodgkin lymphoma (B-NHL). Studies of da-EPOCH-R use daily injections of granulocyte colony-stimulating factor (GCSF) to tailor chemotherapy dosing, and whether 1-time administration of pegylated GCSF (peg-GCSF) is as efficacious has not been addressed. PATIENTS AND METHODS: We reviewed aggressive B-NHL patients treated at our center with first-line da-EPOCH-R for clinician choice of growth factor, and analyzed dose level achieved, rate of unplanned hospitalizations, and patient outcomes. RESULTS: Among 73 patients, 44 received peg-GCSF. Overall, 11 patients (15%) patients achieved dose level 4. Baseline characteristics between peg-GCSF and GCSF groups were similar. The proportion of patients who achieved dose level 4 was comparable in the peg-GCSF group (5 of 44 [11%]) and daily GCSF (6 of 29 [21%]; P = .24). The rate of unplanned hospitalizations, and event-free and overall survival, were also similar between groups. CONCLUSION: We suggest routine use of peg-GCSF is an acceptable alternative to daily GCSF, for patients in whom da-EPOCH-R is selected as first-line treatment for aggressive B-NHL.

Mesothelin variant 1 is released from tumor cells as a diagnostic marker.

The mesothelin family comprises (at least) three variants and includes the precursor for megakaryocyte potentiating factor (MPF). Assaying soluble mesothelin-related protein (SMRP) molecules in serum and other body fluids from patients with certain cancers can provide diagnostically useful information. We have constructed fusion proteins of mesothelin variants 1, 2, and 3, made monoclonal antibodies, and investigated the binding specificity of these and three previously generated monoclonal antibodies to each of the three mesothelin variants. According to flow cytometry, the molecule that is most frequently expressed at the surface of cells from ovarian carcinomas and certain other tumors is mesothelin variant 1. Similarly, SMRP released into ascites from a patient with ovarian carcinoma was shown to have a molecular weight of approximately 40 kDa and, according to sequencing, to be variant 1. A published sandwich ELISA was shown to detect variants 1 and 3 and to be much more sensitive than a newly constructed ELISA, which detects only variant 3, the former being positive in 28 of 41 (68%) sera from patients with ovarian cancer as compared with 6 of 41 sera (15%). A standard curve was constructed to measure SMRP with a limit of detection of 200 pg/mL to facilitate future quantitative studies.

Melanoma cells transfected to express CD83 induce antitumor immunity that can be increased by also engaging CD137.

Interactions between CD83 and its ligand(s) can up-regulate immune responses. M2-CD83 cells, derived by transfecting the M2 clone of mouse melanoma K1735 cells to express mouse CD83, were rejected by syngeneic mice, unless they were injected with a CD83Ig fusion protein. Rejection was mediated by CD4+ and CD8+ T cells plus natural killer cells, whereas rejection of M2-1D8 cells, which express anti-CD137 single-chain variable region fragments (scFv), occurs in the absence of CD8+ T cells. Furthermore, the tumor specificity of the immunity induced by the two cell lines differed. Immunization with live or mitomycin C-treated M2-CD83 cells prevented outgrowth of transplanted M2-WT cells and had therapeutic efficacy against established M2-WT tumors. A highly metastatic clone of K1735 cells, SW1-C, and its subline SW1-P2, which expresses an activating transcription factor 2-driven peptide, were then studied because they have particularly low immunogenicity. Neither SW1-C nor SW1-P2 cells became rejectable after expression of CD83 or anti-CD137 scFv. However, outgrowth of cells from either line was delayed in mice immunized against M2-CD83 or M2-1D8 cells, and immunization with a mixture of mitomycin C-treated cells from M2-CD83 plus M2-1D8 prevented tumor formation by SW1-P2 cells in five of five and by SW1-C cells in three of five mice. We conclude that M2 cells expressing CD83 can induce a tumor-destructive immune response also against SW1 cells and that this response can be made more effective by combining them with M2 cells expressing anti-CD137 scFv. A similar approach may be therapeutically beneficial against certain human cancers.