Follicular B Cells Research Articles

Idelalisib: a review of its use in chronic lymphocytic leukaemia and indolent non-Hodgkin's lymphoma.

Idelalisib (Zydelig®) is a first-in-class, orally administered, phosphatidylinositol 3-kinase-δ inhibitor that was recently approved for the treatment of relapsed chronic lymphocytic leukaemia (CLL), relapsed follicular B-cell non-Hodgkin's lymphoma (NHL) and relapsed small lymphocytic lymphoma (SLL) in the USA and for the treatment of CLL and refractory follicular lymphoma in the EU. In a pivotal phase III trial in patients with relapsed CLL who were not able to receive cytotoxic agents, recipients of idelalisib plus rituximab had significantly improved progression-free survival, overall survival, overall response and lymph node response, compared with recipients of placebo plus rituximab. In a pivotal phase II trial, idelalisib monotherapy was effective in patients with relapsed indolent NHL who were refractory to rituximab and an alkylating agent, including in the subgroups of patients with follicular lymphoma or SLL. Oral idelalisib had a generally manageable adverse event profile, although episodes of serious/fatal diarrhoea or colitis, hepatotoxicity, pneumonitis and intestinal perforation were reported. In conclusion, idelalisib represents an important advance in the treatment of relapsed CLL and relapsed indolent NHL.

Protein kinase CK2 is widely expressed in follicular, Burkitt and diffuse large B-cell lymphomas and propels malignant B-cell growth

Serine-threonine kinase CK2 is highly expressed and pivotal for survival and proliferation in multiple myeloma, chronic lymphocytic leukemia and mantle cell lymphoma. Here, we investigated the expression of α catalytic and β regulatory CK2 subunits by immunohistochemistry in 57 follicular (FL), 18 Burkitt (BL), 52 diffuse large B-cell (DLBCL) non-Hodgkin lymphomas (NHL) and in normal reactive follicles. In silico evaluation of available Gene Expression Profile (GEP) data sets from patients and Western blot (WB) analysis in NHL cell-lines were also performed. Moreover, the novel, clinical-grade, ATP-competitive CK2-inhibitor CX-4945 (Silmitasertib) was assayed on lymphoma cells. CK2 was detected in 98.4% of cases with a trend towards a stronger CK2α immunostain in BL compared to FL and DLBCL. No significant differences were observed between Germinal Center B (GCB) and non-GCB DLBCL types. GEP data and WB confirmed elevated CK2 mRNA and protein levels as well as active phosphorylation of specific targets in NHL cells. CX-4945 caused a dose-dependent growth-arresting effect on GCB, non-GCB DLBCL and BL cell-lines and it efficiently shut off phosphorylation of NF-κB RelA and CDC37 on CK2 target sites. Thus, CK2 is highly expressed and could represent a suitable therapeutic target in BL, FL and DLBCL NHL.

Surrogate light chain is required for central and peripheral B-cell tolerance and inhibits anti-DNA antibody production by marginal zone B cells.

Selection of the primary antibody repertoire takes place in pro-/pre-B cells, and subsequently in immature and transitional B cells. At the first checkpoint, μ heavy (μH) chains assemble with surrogate light (SL) chain into a precursor B-cell receptor. In mice lacking SL chain, μH chain selection is impaired, and serum autoantibody levels are elevated. However, whether the development of autoantibody-producing cells is due to an inability of the resultant B-cell receptors to induce central and/or peripheral B-cell tolerance or other factors is unknown. Here, we show that receptor editing is defective, and that a higher proportion of BM immature B cells are prone to undergoing apoptosis. Furthermore, transitional B cells are also more prone to undergoing apoptosis, with a stronger selection pressure to enter the follicular B-cell pool. Those that enter the marginal zone (MZ) B-cell pool escape selection and survive, possibly due to the B-lymphopenia and elevated levels of B-cell activating factor. Moreover, the MZ B cells are responsible for the elevated IgM anti-dsDNA antibody levels detected in these mice. Thus, the SL chain is required for central and peripheral B-cell tolerance and inhibits anti-DNA antibody production by MZ B cells.

Csnk2β, the Regulatory Subunit of Protein Kinase CK2, modulates Peripheral B Cell Development Repressing Notch2 Signaling and Promoting a Proper B-Cell Receptor Signal Transmission

Background. Serine-threonine protein kinase CK2 has been recently involved in the pathogenesis of B-cell tumors, such as B acute lymphoblastic leukemia, B chronic lymphocytic leukemia, mantle cell lymphoma and multiple myeloma. CK2 acts through a “non-oncogene” addiction mechanism to propel tumor growth, protecting from apoptosis by a phosphorylation-dependent “shielding” mechanism of pro-survival molecules and stimulating oncogenic kinases by helping folding and enzymatic activity. In addition, CK2 has been shown to enhance the transactivation potential of several transcription factors, such as STAT3, NF-κB and c-Myc. The existing data on CK2 function in B cell tumors suggest that this kinase might act as a “hub” downstream signals from surface membrane molecules, like the B-cell (BCR), growth factor and cytokine receptors, as well as from cell-intrinsic pathways – like proteotoxic and DNA-damage-related stress cascades.Aims and methods. To gain insights into the role of CK2 in B-lymphopoiesis and, consequently, in B-cell tumors, we generated CK2β conditional knockout (KO) mice in B-cells by crossing Csnk2β-Flox/Flox mice with CD19-CRE transgenic mice.Results. CK2 kinase activity was decreased in Csnk2β KO B cells. In the bone marrow (BM), Csnk2β KO mice displayed a reduction of B-cells, especially of the B220high IgMint-high recirculating population of transitional and follicular (FO) B cells. Pro-B and pre-B-cell progenitors were slightly reduced in number. In peripheral blood, lymph-nodes, spleen and peritoneal cavity the number of B-cells was markedly reduced. Csnk2β KO mice had lower levels of all the immunoglobulin classes in the serum. The splenic IgDlow IgMhigh B-cell subset was increased whereas the IgDhigh IgMint-low population was decreased. An imbalance between the amount of FO and marginal zone (MZ) B-cells was found with an absolute reduction of FO B cells by approximately 2-folds and an increase of MZ B-cells and MZB cell precursors by up to three folds, on average. Histological and immunofluorescence (IF) analysis revealed a change of size/shape of spleen follicles and a significant expansion of the inter-follicular, marginal zone areas, which appeared to invade the follicle with larger cells. In vitro class-switch recombination assays demonstrated impairment in IgG1 and IgG3 class-switch and a marked reduction of the generation of antibody-producing cells. Anti-IgM stimulation was uncoupled to Ca++ mobilization, indicating a disrupted transmission of the signal from the BCR to the release of Ca++ stores in the endoplasmic reticulum. In vivo sheep red blood cells (SRBC) treatment (T-cell dependent response) showed a conserved up-regulation of GC markers, such as CD38, GL7 and PNA. Nonetheless, the architecture of the reactive follicles was found markedly changed. The analysis of FO, GC and MZ-associated genes showed normal levels of Bcl6, elevated levels of Lrf mRNA and, more significantly, a marked up-regulation of Notch2 target genes, such as Hes1 and Deltex1, in Csnk2β KO B cells. In vivo Notch2 blockage with neutralizing antibodies markedly reduced the MZB cell number in Csnk2β KO mice, indicating a Notch2-dependent MZB expansion associated with Csnk2β loss. High throughput RNAseq analysis was also performed and revealed significant alteration in FOB and MZB-regulating pathways.Conclusions. Here, we found that the β subunit of protein kinase CK2 is a novel regulator of peripheral B cell differentiation. CK2β sustains a proper BCR signal, controls the GC reaction and negatively regulates Notch2 signaling, acting as a master regulator of follicular/marginal zone architecture and terminal homeostasis of FOB and MZB cells. On one side our data enrich the knowledge on the mechanisms regulating B cell development, on the other side they inform about the potential mechanisms altered by CK2 during B-cell tumorigenesis. DisclosuresNo relevant conflicts of interest to declare.

Long-Term Follow-up of a Phase 1 Trial of Idelalisib (ZYDELIG®) in Combination with Bendamustine (B), Bendamustine/Rituximab (BR), Fludarabine (F), Chlorambucil (Chl), or Chlorambucil/Rituximab (ChlR) in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

BACKGROUND: PI3Kδ signaling is critical for the proliferation and survival as well as for homing and tissue retention of malignant B cells. Idelalisib is a first-in-class, targeted, highly selective, oral inhibitor of PI3Kδ with considerable activity as monotherapy and in combination with R in patients with relapsed/refractory CLL, and was recently approved for the treatment of relapsed CLL in combination with R. This report summarizes the long-term follow-up of the Phase 1 combination experience of idelalisib with chemo- and immuno-chemotherapies.METHODS: 74 subjects were sequentially enrolled into one of 5 regimens of idelalisib combined with either B (70 or 90 mg/m2 IV on D1,2 of cycles 1-6, N=18, enrolled Apr 2011-Nov 2011), BR (B: 70 mg/m2 IV on D1,2 of cycles 1-6; R: 375 mg/m2 IV on D1 of cycles 1-6, N=15, enrolled Apr 2011-Aug 2011), F (40 mg/m2 po D1-5 of cycles 1-6, N=12, enrolled Apr 2011-Aug 2011), Chl (10 mg/m2 po D1-7 x 3(min)-12(max) cycles, N=15, enrolled Mar 2012-Aug 2012), or ChlR (N=14, enrolled Mar 2012-Jul 2012). Idelalisib was administered at 100 (4 of the pts receiving B) or 150 mg po BID (all other patients) continuously.Patients on treatment after 48 weeks were eligible to continue idelalisib on an extension study. Clinical responses were evaluated according to published criteria (Hallek 2008; Cheson 2012).RESULTS: Of 74 subjects enrolled, 66% were male. Median age was 65 years, and median time since diagnosis was 8 years with a median of 3 (range 1-9) prior regimens. Overall, prior therapies included R (97%), F (78%), B (45%), and Chl (14%), and 55% of patients were refractory to last therapy. 65% of patients had Rai stage III/IV disease at enrollment. Adverse prognostic factors included del(17p) and/or TP53 mutation (30%), IGHV unmutated status (82%), NOTCH1 mutation (28%).As of 7/15/2014, the median idelalisib exposure for patients of all cohorts was 12.8 (range 1-48) months. 41 (55%) of patients completed the 48 weeks of the primary study, and 20 subjects (27%) were still on treatment on the extension study at the time of analysis.The most common reasons for discontinuation reported by investigators were adverse events (AEs) (15, 20%) or progressive disease (PD) (12, 16%). There were 13 deaths reported on study; 4 patients experienced PD before death.Selected treatment-emergent AEs (any Grade/≥Gr 3, regardless of causality) included diarrhea/colitis (51%/18%), pyrexia (47%/5%), fatigue (35%/7%), cough (35%/0%), nausea (31%/1%), pneumonia (23%/14%), rash (22%/7%), dyspnea (19%/3%), and pneumonitis (3%/3%). Elevation of liver transaminases (TA, any Grade/≥Gr 3) was seen in 37%/14%. Of those, only 1 patient discontinued the study because of (recurrent) TA elevation. Richter’s transformation as category of progressive disease was reported in 1 patient (3%).The ORR was 82% for all 74 patients with a CR rate of 10%. 4 of 74 patients (5%) were not evaluable because of missing follow-up assessments. Among 69 subjects with genetic data available, the ORR in the 22 subjects with either del(17p) and/or TP53 mutation was 68% vs. 87% among 47 subjects with neither aberration. The overall median PFS was not reached at the time of analysis (Figure 1); KM estimate of PFS was 57% [43-72%, 95% CI] at 24 months. Overall median time to response was 1.9 months, and overall median DOR was not yet reached.CONCLUSIONS: These preliminary results in patients with relapsed or refractory disease and multiple prior therapies suggest that idelalisib can be combined with B, BR, F, Chl, and ChlR with acceptable safety and that these combinations have substantial clinical activity. A Phase 3 study evaluating the combination of idelalisib with BR in relapsed CLL is ongoing (NCT01732926). [Display omitted] DisclosuresBarrientos:Gilead Sciences: Research Funding. Off Label Use: Zydelig is a kinase inhibitor indicated for the treatment of patients with: 1) Relapsed chronic lymphocytic leukemia (CLL), in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities; 2) Relapsed follicular B-cell non-Hodgkin lymphoma (FL) in patients who have received at least two prior systemic therapies; and 3) Relapsed small lymphocytic lymphoma (SLL) in patients who have received at least two prior systemic therapies.. Coutre:Gilead Sciences: Research Funding. de Vos:Gilead Sciences: Research Funding. Wagner-Johnston:Gilead Sciences: Research Funding. Flinn:Gilead Sciences: Research Funding. Sharman:Gilead Sciences: Research Funding. Schreeder:Gilead Sciences: Research Funding. Boyd:Gilead Sciences: Research Funding. Rai:Gilead Sciences: Research Funding. Leonard:Gilead Sciences: Research Funding. Kim:Gilead Sciences: Employment, Equity Ownership. Viggiano:Gilead Sciences: Employment, Equity Ownership. Jahn:Gilead Sciences: Employment, Equity Ownership. Furman:Gilead Sciences: Research Funding.

The PI3K Delta Selective Inhibitor Idelalisib Minimally Interferes with Immune Effector Function and B Cell Depletion Mediated By Obinutuzumab (GA101) and Rituximab

Introduction: Idelalisib is a highly selective oral inhibitor of the phosphoinositide 3-kinase delta (PI3Kδ) that is hyperactive in many B-cell malignancies and is critical for the activation, proliferation, survival and trafficking of B lymphocytes. Idelalisib is approved in the US for the treatment of chronic lymphocytic leukemia (CLL) in combination with rituximab and as monotherapy for patients with relapsed follicular B-cell non-Hodgkin lymphoma and small lymphocytic lymphoma who have received at least two prior systemic therapies. Obinutuzumab (GA101) is a glycoengineered type II, CD20 antibody that induces a high level of direct cell death. As a result of glycoengineering, obinutuzumab has increased affinity for FcγRIII on innate immune effector cells resulting in enhanced induction of ADCC and ADCP. Obinutuzumab has been approved for first line treatment of CLL patients in combination with chlorambucil in the US and Europe and is currently in pivotal clinical trials in indolent NHL and DLBCL. Previous work has shown the covalent BTK inhibitor ibrutinib can interfere with the immune effector function and ultimately in vivo efficacy of rituximab in preclinical models (Kohrt et al., Blood, 2014). As PI3K isoforms also play a role in immune effector cells and FcγR signaling we investigated the impact of PI3Kδ inhibition by the PI3Kδ selective inhibitor idelalisib on the immune effector function of obinutuzumab and rituximab.Experimental methods: The impact of idelalisib on NK cell mediated ADCC induction by obinutuzumab and rituximab was investigated in LDH release assays using WIL2-S, SU-DHL4 and Z138 target cells at plasma protein-binding adjusted clinically relevant concentrations mimicking exposure in patients. As a surrogate for NK cell activation CD16 levels and up-regulation of the degranulation marker CD107a were assessed by FACS. The impact on monocyte-derived macrophage mediated ADCP of WIL2-S cells was measured in a flow cytometry-based phagocytosis assay. Finally, depletion of CD19 positive B cells was determined in whole blood from healthy volunteers in flow cytometry-based whole blood assay.Results: In ADCC assays, no impact of idelalisib on ADCC at saturating concentration of obinutuzumab or rituximab (>1ug/ml) can be detected in LDH release assays with tumor cells targets (N=9 donors for WIL2-S, N>3 donors for SU-DHL-4 and Z138). Idelalisib did not alter obinutuzumab or rituximab ability to kill tumor cells by ADCC at low E:T ratio. Little to no increase of obinutuzumab or rituximab EC50 for LDH release, CD16 down regulation, or degranulation of NK cells could be detected depending on donor effector cells. ADCP assays were conducted with M2c polarized macrophages using WIL2-S as targets. Less than 30% inhibition of ADCP was observed in this assay at idelalisib concentration at protein binding-adjusted clinical Cmax. At idelalisib Cmax (4200 nM) the EC50 of obinutuzumab-mediated B cell depletion in healthy human whole blood was increased 3 to 5 times, whereas at Cmin (760 nM) idelalisib did not significantly influence obinutuzumab EC50 or maximal B cell depletion.Conclusions: PI3Kδ inhibition by idelalisib has minimal impact on the immune effector function of obinutuzumab (GA101) and rituximab as measured in NK cell-mediated ADCC, macrophage-mediated ADCP and whole blood B-cell depletion. DisclosuresHerter:Roche: Employment. Palazzo:Gilead Sciences: Employment. Bacac:Roche: Employment. Grosmaire:Gilead Sciences: Employment. Frey:Gilead Sciences: Employment. Pflanz:Gilead Sciences: Employment. Liu:Gilead Sciences: Employment. Tannheimer:Gilead Sciences: Employment. Umana:Roche: Employment. Klein:Roche: Employment, Equity Ownership, Patents & Royalties. Queva:Gilead Sciences: Employment.

Mature Follow up from a Phase 2 Study of PI3K-Delta Inhibitor Idelalisib in Patients with Double (Rituximab and Alkylating agent)-Refractory Indolent B-Cell Non-Hodgkin Lymphoma (iNHL)

Introduction: Rituximab-alkylator combinations are the standard therapies for patients (pts) with iNHL, however, refractory disease nearly uniformly develops. Once iNHL becomes “double-refractory” to both rituximab + alkylating agents, there are limited options to induce durable remissions. PI3K-delta signaling is critical for activation, proliferation and survival of B cells, and is hyperactive in many B-cell malignancies. Idelalisib, a selective oral inhibitor of PI3Kd, demonstrated considerable clinical activity in double-refractory iNHL (Gopal NEJM 2014). FDA granted accelerated approval for Idelalisib (Zydelig®) in patients who have received at least two prior systemic therapies with relapsed FL or SLL. Based on these encouraging initial results, we now describe long-term follow up, safety, and remission durations of this double-refractory iNHL population treated with idelalisib. Methods: Eligible iNHL pts included those with measurable disease refractory to both rituximab and an alkylating agent. Refractory was defined as lack of response to, or progression of lymphoma within 6 months of completion of index therapy, confirmed by imaging. Idelalisib 150 mg PO BID was administered continuously until disease progression or intolerance. Responses were evaluated by an independent review committee, using standard criteria (Cheson, 2007, and Owen 2013). The new data cutoff date for this analysis was June 2014, 20 months after the last patient enrolled. Results: Enrolled pts (N = 125) had a median age of 64 years and included follicular lymphoma (FL) n=72 (58%), small lymphocytic lymphoma (SLL) n=28 (22%), marginal zone lymphoma (MZL) n=15 (12%) and lymphoplasmacytic lymphoma (LPL)/Waldenstrom9s macroglobulinemia (WM) n=10 (8%). The median number of prior therapies was 4 [range 2-12], including bendamustine/rituximab (BR) (n=60) and rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) (n=56) and autologous transplant (n=14). 81 pts (65%) had prior bendamustine, of which 61/81 (75%) were refractory. 112 pts (90%) were refractory to their last regimen, and 99 pts (79%) were refractory to ≥2 regimens. 38 pts (30%) had elevated LDH, and 33 pts (26%) had bulky disease >7 cm. The median time to progression from last prior therapy was 3.9 months. With a median exposure of 11.1 months (range 0.7 to 35.4), the overall response rate (ORR) is 56% (95% CI = 46.8-64.9) with 70 responders, comprising 12 CRs (9.6%), 58 PRs (46.4%). The median time to response was 1.9 months (time of first evaluation) and time to CR was 4.5 months. There were 43 pts with stable disease (SD) (34.4%). 90% of pts experienced some decrease in tumor burden. ORR for iNHL subtypes is: FL (54%), SLL (61%), MZL (47%), and LPL/WM (70%). CR rate for iNHL subtypes is: FL (14%), SLL (4%), MZL (7%), and LPL/WM (0%). Among responders, median DOR is 13.9 (0.03-31.3) months. DOR for iNHL subtypes in months (Figure 1) is: FL 11.8, SLL 13.9, MZL 18.4, and LPL/WM (not yet reached). Median PFS for all pts is 11.0 months, in comparison to a median PFS of the last prior regimen of 3.9 months (p The adverse events include (total%/≥ grade 3%) diarrhea/colitis (50/18), fatigue (30/2), nausea (31/2), cough (32/0), pyrexia (30/2), dyspnea (18/5), rash (14/2), pneumonia (14/11), and pneumonitis (4/3). Based on central laboratory measurements, Grade ≥3 ALT/AST elevations occurred in 18 pts (14%). Drug was temporarily held in these pts, and 11/15 pts (73%) were re-treated without recurrence of ALT/AST elevation. Overall, 30 pts (24%) have discontinued therapy due to adverse events. Conclusions: The prolonged administration of idelalisib was well tolerated, had an acceptable safety profile, and was highly effective in inducing and maintaining remissions in double-refractory iNHL population with an ORR of 56%, PFS of 11 months, and DOR of 13.9 months. The response rate and long term duration of responses in the small number of subjects with LPL/WM is very promising, and will be evaluated in larger trials of this disease. The observed disease control compared to prior regimens suggests the potential for prolonged clinical benefit in this challenging patient population with unmet medical need. Disclosures Gopal:Gilead Sciences: Research Funding. Off Label Use: Zydelig is a kinase inhibitor indicated for the treatment of patients with: 1) Relapsed chronic lymphocytic leukemia (CLL), in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities; 2) Relapsed follicular B-cell non-Hodgkin lymphoma (FL) in patients who have received at least two prior systemic therapies; and 3) Relapsed small lymphocytic lymphoma (SLL) in patients who have received at least two prior systemic therapies.. Kahl:Gilead Sciences: Research Funding. de Vos:Gilead Sciences: Research Funding. Wagner-Johnston:Gilead Sciences: Research Funding. Schuster:Gilead Sciences: Research Funding. Jurczak:Gilead Sciences: Research Funding. Flinn:Gilead Sciences: Research Funding. Flowers:Gilead Sciences: Research Funding. Martin:Gilead Sciences: Research Funding. Viardot:Gilead Sciences: Research Funding. Blum:Gilead Sciences: Research Funding. Goy:Gilead Sciences: Research Funding. Davies:Gilead Sciences: Research Funding. Zinzani:Gilead Sciences: Research Funding. Dreyling:Gilead Sciences: Research Funding. Holes:Gilead Sciences: Employment, Equity Ownership. Sorensen:Gilead Sciences: Employment, Equity Ownership. Godfrey:Gilead Sciences: Employment, Equity Ownership. Salles:Gilead Sciences: Research Funding.

Update on a Phase 2 Study of Idelalisib in Combination with Rituximab in Treatment-Naïve Patients ≥65 Years with Chronic Lymphocytic Leukemia (CLL) or Small Lymphocytic Lymphoma (SLL)

Background: The selectivePI3K-delta inhibitor Idelalisib (Zydelig®, IDELA), in combination with rituximab (R), has been previously reported to yield a 97% ORR in treatment naïve patients (pts) ≥65 years with CLL or SLL (O’Brien, ASCO 2013). This report is an update on that initial cohort of study pts.Methods: Treatment-naive pts ≥65 yrs with CLL or SLL were treated with R 375 mg/m2 weekly x 8 and idelalisib 150 mg bid continuously for 48 weeks (primary study). Pts completing 48 weeks without progression could continue to receive idelalisib on an extension study. Response assessment, at pre-determined time points, was investigator determined using either physical exam or CT scans per investigator discretion, based on modified IWCLL guidelines (Hallek 2008, Cheson 2012).Results: 64 pts were enrolled, 59 CLL/5 SLL, median age 71 yrs (range: 65-90), 63% male, Rai stage III/IV 13/30 (%), nodes ≥5 cm in 11%, WHO 0/1/2 in 42/56/2 (%). Adverse risk factors: del(17p) and/or TP53 mutation in 14%, del(11q) in 16%, IGHV unmutated in 58%, median β2-microglobulin 4.0 mg/L (range 1.9-15.8). Disposition: 43 pts completed the 48 wk primary study and 41 entered the extension study. 21 pts discontinued from the primary study (17 AE, 1 withdrawn consent, 3 deaths [pneumonitis; sepsis; metastatic melanoma with pneumonia]); an additional death occurred within 30 days of discontinuation due to pneumonitis. There were 17 discontinuations from the extension study (9 AE, 2 withdrawn consent, 1 investigator request, 4 PD, 1 death [myocardial infarction]), leaving 24 pts ongoing. The median IDELA exposure is 22.9 mos (range 0.8-45.3), with 13 (20%) pts treated for more than 36 months. The ORRis 97% (78% PR, 19% CR) with 3% nonevaluable; median time to response is 1.9 mos (range 1.6-5.7). The Kaplan-Meier (KM) estimated median PFS is not reached (NR), 95% CI (37.3 mo, –). The KM estimated DOR is NR, 95% CI (35.4,–). Of note, 9/9 pts with del(17p) and/or TP53 mutation responded (3 CR, 6 PR); 5 discontinued for AE (4) or investigator request (1) and 4 remain on treatment for 28, 34, 40 and 41 months. The most frequent Gr ≥3 AEs (%) were diarrhea/colitis (42), pneumonia (19), rash (13), dehydration (8), UTI (6), dyspnea (5) and respiratory failure (5). In addition, pneumonitis developed in 2 pts (3%), both Gr 5, and one pt with diverticulitis developed bowel perforation. The median time to onset of Gr ≥3 diarrhea/colitis was 9.5 mo, (range 3-29). Rechallenge was attempted in 21 of the 27 pts with Gr ≥3 diarrhea/colitis, and 12 pts were able to resume IDELA for ≥ 120 days.15 (23%) pts developed Gr ≥3 ALT or AST elevation, all recovering, with successful resumption of IDELA, at a reduced dose, in 12. In total, 29 (45%) pts had one or more treatment-emergent AEs leading to IDELA dose reduction.Conclusions: IDELA + R is highly active, rapidly inducing responses in 97% of treatment-naïve older pts with CLL and SLL. The responses are durable, including in those with del(17p)/TP53 mutation. Diarrhea/colitis was the most common Gr ≥3 AE, and IDELA was successfully reintroduced in 44% of the affected pts. Ongoing studies are further investigating the role of IDELA in the frontline setting. DisclosuresO’Brien:Gilead Sciences: Research Funding. Off Label Use: Zydelig is a kinase inhibitor indicated for the treatment of patients with: 1) Relapsed chronic lymphocytic leukemia (CLL), in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities; 2) Relapsed follicular B-cell non-Hodgkin lymphoma (FL) in patients who have received at least two prior systemic therapies; and 3) Relapsed small lymphocytic lymphoma (SLL) in patients who have received at least two prior systemic therapies.. Lamanna:Gilead Sciences: Research Funding. Kipps:Gilead Sciences: Research Funding. Flinn:Gilead Sciences: Research Funding. Zelenetz:Gilead Sciences: Research Funding. Burger:Gilead Sciences: Research Funding. Holes:Gilead Sciences: Employment, Equity Ownership. Cho:Gilead Sciences: Employment, Equity Ownership. Dubowy:Gilead Sciences: Employment, Equity Ownership. Coutre:Gilead Sciences: Research Funding.

Durable Responses Following Treatment with the PI3K-Delta Inhibitor Idelalisib in Combination with Rituximab, Bendamustine, or Both, in Recurrent Indolent Non-Hodgkin Lymphoma: Phase I/II Results

Durable Responses Following Treatment with the PI3K-Delta Inhibitor Idelalisib in Combination with Rituximab, Bendamustine, or Both, in Recurrent Indolent Non-Hodgkin Lymphoma: Phase I/II Results

A Phase 2 Study of Idelalisib Monotherapy in Previously Untreated Patients ≥65 Years with Chronic Lymphocytic Leukemia (CLL) or Small Lymphocytic Lymphoma (SLL)

BACKGROUND: PI3K-delta (δ) is critical for activation, proliferation and survival of B cells and plays a role in homing and retention in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib (Zydelig, IDELA,), a potent and selective orally administered inhibitor of PI3Kδ, in combination with rituximab weekly x 8 has yielded an ORR of 97% in patients (pts) ≥65 years with previously untreated CLL or SLL (O’Brien, ASCO 2013). This report describes the preliminary experience in treating a similar cohort of pts with IDELA monotherapy.METHODS: Enrollment began in November, 2013. Treatment-naive pts ≥65 yrs with CLL or SLL, requiring treatment per IWCLL 2008 criteria, and with measurable lymphadenopathy, were treated with IDELA 150 mg bid continuously. Response assessment, at pre-determined time points, was investigator determined using either physical exam or CT scans per investigator discretion, using modified IWCLL guidelines (Hallek 2008, Cheson 2012).RESULTS: As of 21 July 2014, 37 pts were enrolled: 78% male; CLL/SLL in 92%/8%; median age 70 years; 73% Rai III or IV; WHO 0-1/2 in 97%/3%. 46% had ≥1 B-symptom. Hepatomegaly and splenomegaly were present in 14% and 57% respectively. Adverse prognostic factors: 14% del(17p) and/or TP53 mutated; 22% del(11q); 41% IGHV unmutated; β-2 microglobulin median 4.35 mg/L (range: 2.1-12.4). The median idelalisib exposure was 4.8 months (range 0.9-8.5). There has been one discontinuation at 3 mo for respiratory distress, assessed as related to a prior condition. The median absolute lymphocyte count was 59.7 K/µl (range: 0.8-294) at baseline peaking at 100 K/µl (range: 2-385) at week 4. 27 pts were evaluable for response, having reached the first evaluation time point of 8 weeks. Of these 27, the ORR was 81% with 9 (33%) PR and 13 (48%) PR with lymphocytosis. Splenomegaly has responded in 88% of 17 evaluable pts and hepatomegaly in 75% of 4 evaluable pts. The most frequent treatment emergent adverse events (TEAE) (% all Grade/% Grade ≥3) were rash (27/3), URI (16/0), constipation (14/0), cough (14/0), nausea (11/0), pyrexia (11/0), arthralgia (8/0), back pain (8/0), diarrhea (8/3), and pneumonia (8/5). Pneumonitis was observed in 2 pts (5%), Gr ≥3 in 1(3%). Gr ≥3 treatment emergent lab abnormalities included transaminase elevation (8%), anemia (5%), and neutropenia (20%); there was no Gr ≥3 thrombocytopenia. One pt had a TEAE leading to dose reduction.CONCLUSIONS: IDELA has substantial single agent activity in treatment-naïve pts with CLL or SLL. Early lymphocytosis is observed with monotherapy in this population, as opposed to an attenuation of lymphocytosis seen in the earlier cohort treated with IDELA plus weekly rituximab. IDELA was well tolerated and had a manageable safety profile in this preliminary analysis. DisclosuresZelenetz:Gilead Sciences: Research Funding. Off Label Use: Zydelig is a kinase inhibitor indicated for the treatment of patients with: 1) Relapsed chronic lymphocytic leukemia (CLL), in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities; 2) Relapsed follicular B-cell non-Hodgkin lymphoma (FL) in patients who have received at least two prior systemic therapies; and 3) Relapsed small lymphocytic lymphoma (SLL) in patients who have received at least two prior systemic therapies.. Lamanna:Gilead Sciences: Research Funding. Kipps:Gilead Sciences: Research Funding. Coutre:Gilead Sciences: Research Funding. O’Brien:Gilead Sciences: Research Funding. Aiello:Gilead Sciences: Employment, Equity Ownership. Cho:Gilead Sciences: Employment, Equity Ownership. Dubowy:Gilead Sciences: Employment, Equity Ownership. Flinn:Gilead Sciences: Research Funding.

Long-Term Follow-up of a Phase 1 Study of Idelalisib (ZYDELIG®) in Combination with Anti-CD20 Antibodies (Rituximab [R] or Ofatumumab [O]) in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

Long-Term Follow-up of a Phase 1 Study of Idelalisib (ZYDELIG®) in Combination with Anti-CD20 Antibodies (Rituximab [R] or Ofatumumab [O]) in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

A Phase Ib Study of Obinutuzumab Combined with Lenalidomide for Relapsed/Refractory Follicular B-Cell Lymphoma

BACKGROUND:Lenalidomide exerts anti-proliferative activity on lymphoma cells, enhances T- and NK-cell function, and improves ADCC. The combination of lenalidomide and rituximab (R2) has been shown to be synergistic in pre-clinical models and in patients with relapsed and first-line follicular lymphoma (FL). Obinutuzumab, a unique type II glycoengineered monoclonal anti-CD20 antibody with increased ADCC and increased direct cell death induction compared to rituximab, has shown promising efficacy in NHL. Combining obinutuzumab with lenalidomide might be even more efficient than R2 combination. In 2012, we started a phase Ib/II study to assess the safety and efficacy of this combination (ClinicalTrials.gov: NCT01582776, GALEN) for relapsed/refractory lymphoma patients. Here, we report the phase Ib part whose primary objective was to determine the maximum tolerated dose (MTD) of lenalidomide in combination with a fixed dose of obinutuzumab.METHODS:To identify the MTD of lenalidomide, four patient cohorts received escalating doses (10, 15, 20, and 25 mg) of daily oral lenalidomide on days 1-21 of a 28-day cycle for the first cycle and on days 2-22 of a 28-day cycle from cycles 2 to 6. Intravenous infusions of obinutuzumab at a flat dose of 1000mg were given on Days 8, 15, and 22 of the first cycle and at D1 of cycles 2 to 6 (total of 8 infusions). Steroid premedication was mandatory before first obinutuzumab infusion. All subjects were required to take daily aspirin (100 mg) for deep vein thrombosis (DVT) prophylaxis during study period. Subjects who were unable to tolerate aspirin and subjects with prior history of DVT or at high risk received low molecular weight heparin therapy or warfarin (coumadin) treatment. Dose was escalated in a 3+3 design based on dose limiting toxicity (DLT) assessment during cycle 1RESULTS:20 patients with FL ([10 mg: 7; 15 mg: 3; 20 mg: 6, 25 mg: 4] QD) were enrolled between Oct 2012 and Feb 2014 at 7 centers, 10 men/10 women, median age 64 (range, 39–80) years, 15 with Ann Arbor stage IV, median number of prior systemic therapies 2 (range, 1–5) and 8 were rituximab refractory. One patient was withdrawn before receiving any treatment due to neutropenia occurring at baseline screening. Median number of cycles was 6 (range, 1–6). We observed 163 AEs (87 grade 1; 53 grade 2; 21 grade 3; one grade 4 and one grade 5). The most common AEs (All grades, ≥20% patients) were neutropenia (10/19; 53%), constipation (10/19; 53%) asthenia (7/19; 37%), upper respiratory tract infection (7/19; 37%), rash/cutaneous eruption (5/19; 26%), cough (5/19; 26%), diarrhea (4/19 ; 26%) and fever (4/19, 21%). Grade (G) 3/4 AEs occurring in ≥2 patients only consisted in neutropenia (8/19; 42%). Infusion related reactions occurred in 3 patients and did not exceed grade 2. Four DLTs have occurred in 2 patients: one unexplained death (G5) at 10 mg in the setting of G3 worsening pleural effusion; another patient treated at 20 mg had G3 pulmonary infection with G3 hypokalemia, both deemed unrelated to study treatment. The MTD was not reached. Among 19 evaluable patients, 13 (68%) had an overall response according to Cheson 1999 criteria: 7 achieved CR, 3 CRu and 3 PR.CONCLUSION:Oral lenalidomide plus obinutuzumab is well tolerated and effective in patients with relapsed or refractory FL. Recommended dose of lenalidomide was established at 20mg based on the increased incidence of grade 3/4 neutropenia between cycle 2 and 6 at 25mg. The Phase II partis currently assessing theefficacy of lenalidomide (at 20 mg) in combination with obinutuzumab in 2 separate populations of patients: relapsed/refractory follicular lymphoma in one cohort and relapsed/refractory aggressive lymphoma (diffuse large B-cell lymphoma and mantle cell lymphoma) in another cohort. DisclosuresMorschhauser:Celgene: advisory boards, advisory boards Other, Honoraria; Genentech/roche: Honoraria, travel grants Other. Off Label Use: obinutuzumab and lenlidomide in relapsed follicular lymphoma. Salles:celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees; roche: advisory boards, advisory boards Other, Honoraria, Research Funding. Le Gouill:Roche: Consultancy. Tilly:Roche/Genetech: advisory boards, advisory boards Other, Honoraria; Celgene: advisory boards Other, Honoraria. Cartron:roche: Consultancy, Honoraria; celgene: Honoraria.

Artificially and Sugar-Sweetened Carbonated Beverage Consumption Is Not Associated with Risk of Lymphoid Neoplasms in Older Men and Women

Background: Concern about the carcinogenic potential of aspartame was raised after an increase in lymphomas and leukemia was reported in an animal study at doses similar to human exposure. Two prospective cohort studies published after the report found inconsistent results for estimated aspartame intake, artificially sweetened beverage consumption, and risk of lymphoid neoplasms.Objective: The objective of this study was to examine associations of artificially and sugar-sweetened carbonated beverage consumption (for comparison) and aspartame intake with risk of non-Hodgkin lymphoma (NHL) overall and by major histologic subtype in the Cancer Prevention Study-II Nutrition Cohort.Methods: Among 100,442 adult men and women who provided information on diet and lifestyle factors in 1999, 1196 NHL cases were verified during a 10-y follow-up period. Cox proportional hazards regression was used to estimate multivariable-adjusted RRs and 95% CIs.Results: In women and men combined, there were no associations of consumption of ≥1 (355 mL) servings/d of artificially (RR: 0.92; 95% CI: 0.73, 1.17; P-trend: 0.14) or sugar- (RR: 1.10; 95% CI: 0.77, 1.58; P-trend: 0.62) sweetened carbonated beverages with NHL risk, compared to no consumption (P-heterogeneity by gender: 0.11–1.00). Similarly, aspartame intake was not associated with NHL risk (RR: 1.02; 95% CI: 0.84, 1.24; P-trend: 0.69, top vs. bottom quintile). Associations with NHL subtype (multiple myeloma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, and follicular and other B-cell lymphoma) were generally null.Conclusion: These findings do not support associations of daily consumption of artificially or sugar-sweetened carbonated beverages, or aspartame, with NHL risk.

Diagnosis of Primary Follicular B-Cell Non-Hodgkin’s Lymphoma of the Spleen by EUS-Guided FNA

Diagnosis of Primary Follicular B-Cell Non-Hodgkin’s Lymphoma of the Spleen by EUS-Guided FNA

Idelalisib: First-in-class oral therapy targets three types of blood cancers

Idelalisib (Zydelig—Gilead Sciences), an oral therapy for the treatment of three B-cell blood cancers, has received FDA approval. The new drug targets chronic lymphocytic leukemia (CLL), follicular B-cell non– Hodgkin lymphoma (FL), and small lymphocytic lymphoma (SLL).

Idelalisib: first global approval.

Idelalisib (Zydelig(®)) is a highly specific small-molecule phosphatidylinositol-3-kinase (PI3Kδ) inhibitor that has been developed as an oral treatment for B cell haematological cancers.It has received its first approval in the US in July 2014 for the treatment of relapsed chronic lymphocytic leukaemia(CLL), relapsed follicular B-cell non-Hodgkin lymphoma(NHL) and relapsed small lymphocytic lymphoma (SLL) [corrected]. Idelalisib is under regulatory review in the EU-where it has received a positive opinion from the European Medicines Agency Committee for Medicinal Products for Human Use-and in clinical development for CLL in Australia and Canada. This article summarizes the milestones in the development of Idelalisib leading to this first approval for relapsed CLL, NHL and SLL.

Correction: The Development and Survival but Not Function of Follicular B Cells Is Dependent on IL-7Rα Tyr449 Signaling

Correction: The Development and Survival but Not Function of Follicular B Cells Is Dependent on IL-7Rα Tyr449 Signaling

TGF-β upregulates CD70 expression and induces exhaustion of effector memory T cells in B-cell non-Hodgkin’s lymphoma

Transforming growth factor beta (TGF-β) has an important role in mediating T-cell suppression in B-cell non-Hodgkin lymphoma (NHL). However, the underlying mechanism responsible for TGF-β-mediated inhibition of effector memory T (Tm) cells is largely unknown. As reported here, we show that exhaustion is a major mechanism by which TGF-β inhibits Tm cells, and TGF-β mediated exhaustion is associated with upregulation of CD70. We found that TGF-β upregulates CD70 expression on effector Tm cells while it preferentially induces Foxp3 expression in naive T cells. CD70 induction by TGF-β is Smad3-dependent and involves IL-2/Stat5 signaling. CD70+ T cells account for TGF-β-induced exhaustion of effector Tm cells. Both TGF-β-induced and preexisting intratumoral CD70+ effector Tm cells from B-cell NHL have an exhausted phenotype and express higher levels of PD-1 and TIM-3 compared with CD70- T cells. Signaling transduction, proliferation and cytokine production are profoundly decreased in these cells, and they are highly susceptible to apoptosis. Clinically, intratumoral CD70-expressing T cells are prevalent in follicular B-cell lymphoma (FL) biopsy specimens, and increased numbers of intratumoral CD70+ T cells correlate with an inferior patient outcome. These findings confirm TGF-β-mediated effector Tm cell exhaustion as an important mechanism of immune suppression in B-cell NHL.

Fine Mapping of the 15q21 Region Implicates TP53BP1 and B2M in the Lymphomagenesis of Follicular and Diffuse Large B-Cell Lymphomas

Background and aim: Recent studies focusing on the discovery of common alterations across cases suffering from follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) have reported loss of heterozygosity (LOH) and deletions events targeting the 15q21 region, indicating the relevance of this region in the lymphomagenesis of FL and DLBCL. Herein, we investigated the genetic structure of this region by studying identified LOH and copy-loss events and examined this region in the lymphomagenesis of FL and DLBCL. Methods: Fine mapping of the genomic region between the 15q15.1 and 15q21.1 loci was performed using data from copy number variation (CNV) and high resolution LOH analyses of FL (n=21) and DLBCL (n=21) cases. Validation of LOH of this region was performed using microsatellites followed by quantitative-PCR (qPCR) to measure the transcriptional abundance of TP53BP1 and B2M. Also, direct sequencing of exons 1 and 2 of B2M was performed on tumor DNA from 24 FL and 23 DLBCL samples. Results: The integration of LOH and CNV data identified copy-loss alterations at the 15q21 loci spanning a 7.5 Mb region, covering two LOH regions, termed LOH-1 and LOH-2. The LOH-1 region spans 3.4 Mb and contains 53 genes, from which TP53BP1 (tumor-protein-p53-binding-protein-1) and B2M (Beta-2-Microglobulin) were identified as the most likely target genes due to their roles in DNA double strand break (DSB) repair and immune recognition, respectively. Expression analyses revealed a significant up-regulation of TP53BP1 in NHL with LOH, but no significant changes in B2M expression were observed. Direct sequencing of exons 1 and 2 in B2M in FL and DLBCL identified two monoallelic microdeletions associated with DLBCL. Conclusion: This study identified that deletion mapping to the 15q21 locus cover two LOH regions. LOH of the TP53BP1 and B2M genes appear to be common alterations in FL and DLBCL tumorigenesis.

Deletion Of The Von Hippel-Lindau Gene Interferes With The Development Of Peripheral B-Cell Subsets

The development of hematopoietic cells occurs in highly specialized microenvironments within bone marrow, thymus and spleen. Hematopoietic stem and progenitor cells are positioned at the lowest end of a bone marrow oxygen gradient, which implies a role for the hypoxic-response pathway in regulating hematopoiesis. In this pathway the von Hippel-Lindau protein (pVhl) is the central negative regulator and continuously mediates the proteasomal destruction of the hypoxia-inducible factor-1α (Hif-1α). Under hypoxic conditions Hif-1α destruction is inhibited and results in the expression of hypoxia-inducible genes.In order to study the role of pVhl in hematopoiesis we crossed Vhl conditional mice with vav-iCre mice to induce a constitutive hematopoiesis-specific Vhl deletion (VhlKOvav). As expected, we observed a dramatic expansion of spleen erythropoiesis, however bone marrow lin-Sca-1+c-kit+CD48-CD150+ hematopoietic stem cell numbers of VhlKOvav mice did not significantly differ from control mice. The most striking observation in VhlKOvav mice was that B-cell numbers in bone marrow and spleen were decreased by 53% and 78%, respectively. In order to exclude that the loss of B-cells in VhlKOvav mice was due to a B-cell extrinsic effect we crossed Vhl conditional mice to the B-cell specific deleter lines CD19-Cre and Mb1-Cre (VhlKOCD19 and VhlKOMb1 mice). Flow cytometric analysis also revealed decreased peripheral B-cell numbers in VhlKOCD19 mice and an even more pronounced B-cell loss in VhlKOMb1 mice (B-cells spleen, mean±SEM; control (n=9), 77±2.4x106; VhlKOMb1 (n=12), 1.3±0.2x106; p<0.001). This demonstrated that pVhl is cell-autonomously required for the normal development of the B-cell compartment. To more accurately define the Vhl-null B-cell developmental defect we analyzed bone marrow B-cell subsets of VhlKOMb1 and control mice. Early B-cell progenitor numbers defined by the surface markers B220, CD43, CD24, BP-1 (Hardy's classification, fractions A-D) of VhlKOMb1 mice were not altered. In contrast, we observed a significant 41% reduction of the immature B220+CD43-IgM+IgD- and a 46% reduction of the mature B220+CD43-IgM+IgD+ bone marrow VhlKOMb1 B-cell numbers compared to controls. In peripheral blood VhlKOMb1 immature and mature B-cell numbers were even more decreased (by 81% and 86%, respectively). We hypothesized that increased CXCR4 expression, which is negatively regulated by pVhl, could be responsible for the decreased bone marrow egress of immature bone marrow B-cells. Indeed, we observed a more than twofold increase of CXCR4 expression of VhlKOMb1 compared to control bone marrow immature B-cells (MFI, mean±SEM; control (n=3), 72±15; VhlKOMb1 (n=3), 162±23; p<0.05). Strikingly, VhlKOMb1 spleens were almost devoid of follicular B220+CD21/35intmCD23+IgD+IgM+ and marginal zone B220+CD21/35highCD23-IgMhigh B-cells and accordingly follicular structures could not be observed in histological sections. In VhlKOMb1 lymph nodes the follicular B-cell numbers were also dramatically decreased. Next, we flow sorted residual splenic VhlKOMb1 B-cells and were able to confirm deletion of the Vhl-gene by PCR. Target genes of the hypoxic-response pathway such as Pgk1, Vegf and Bnip3 were 10- to more than 100-fold higher expressed in sorted VhlKOMb1 compared to control B-cells. As a possible reason for the low VhlKOMb1 peripheral B-cell numbers we identified a more than twofold reduction in CD62L expression by immature blood B-cells (MFI, mean±SEM; control (n=3), 3127±250; VhlKOMb1 (n=3), 1528±66; p<0.05) which presumably impaired their homing ability to peripheral lymphoid organs. Additionally, we detected an increased B-cell apoptosis rate of VhlKOMb1 B-cells in the spleen. Finally, we were able to show that decreased follicular splenic B-cell numbers of VhlKOCD19 mice could be completely rescued by additionally breeding Hif-1α conditional alleles into the system (Hif-1αVhlKOCD19mice).In summary, we identified pVhl as a key regulator of peripheral B-cell maturation. We show that pVhl-mediated negative regulation of the hypoxic-response pathway is required for normal peripheral B-cell differentiation. Our data suggest that B-cell pVHL loss-of-function leads to decreased bone marrow egress and decreased lymphoid organ homing of immature B-cells mediated by the dysregulation of CXCR4 and CD62L. Disclosures:No relevant conflicts of interest to declare.