The IL-15-AKT-XBP1s signaling pathway contributes to effector functions and survival in human NK cells.

Interleukin 15 (IL-15) is one of the most important cytokines that regulate the biology of natural killer (NK) cells1. Here we identified a signaling pathway-involving the serine-threonine kinase AKT and the transcription factor XBP1s, which regulates unfolded protein response genes2,3-that was activated in response to IL-15 in human NK cells. IL-15 induced the phosphorylation of AKT, which led to the deubiquitination, increased stability and nuclear accumulation of XBP1s protein. XBP1s bound to and recruited the transcription factor T-BET to the gene encoding granzyme B, leading to increased transcription. XBP1s positively regulated the cytolytic activity of NK cells against leukemia cells and was also required for IL-15-mediated NK cell survival through an anti-apoptotic mechanism. Thus, the newly identified IL-15-AKT-XBP1s signaling pathway contributes to enhanced effector functions and survival of human NK cells.

TTK/MPS1 inhibitor OSU-13 targets the mitotic checkpoint and is a potential therapeutic strategy for myeloma.

Despite substantial recent advances in treatment, multiple myeloma (MM) remains an incurable disease, with a shortage of treatment options for patients with high-risk disease, warranting the need for novel therapeutic targets and treatment approaches. Threonine and tyrosine kinase (TTK), also known as monopolar spindle 1 (MPS1), is a kinase essential for the mitotic spindle checkpoint whose expression correlates to unfavorable prognosis in several cancers. Here, we report the importance of TTK in MM, and the effects of the TTK inhibitor OSU-13. Elevated TTK expression correlated with amplification/ gain of 1q21 and decreased overall and event-free survival in MM. Treatment with OSU-13 inhibited TTK activity efficiently and selectively at a similar concentration range to other TTK inhibitor clinical candidates. OSU-13 reduced proliferation and viability of primary human MM cells and cell lines, especially those with high 1q21 copy numbers, and triggered apoptosis through caspase 3 and 7 activation. In addition, OSU-13 induced DNA damage and severe defects in chromosome alignment and segregation, generating aneuploidy. In vivo, OSU-13 decreased tumor growth in mice with NCI-H929 xenografts. Collectively, our findings reveal that inhibiting TTK with OSU-13 is a potential therapeutic strategy for MM, particularly for a subset of high-risk patients with poor outcome.

Aging Phenotypes and Restoring Functional Deficits in Older Adults With Hematologic Malignancy.

BACKGROUND: Gauging fitness remains a challenge among older adults with hematologic malignancies, and interventions to restore function are lacking. We pilot a structured exercise intervention and novel biologic correlates of aging using epigenetic clocks and markers of immunosenescence to evaluate changes in function and clinical outcomes. METHODS: Older adults (n=30) with hematologic malignancy actively receiving treatment were screened and enrolled in a 6-month exercise intervention, the Otago Exercise Programme (OEP). The impact of the OEP on geriatric assessment metrics and health-related quality of life were captured. Clinical outcomes of overall survival and hospital utilization (inpatient length of stay and emergency department use) in relationship to geriatric deficits were analyzed. RESULTS: Older adults (median age, 75.5 years [range, 62-83 years]) actively receiving treatment were enrolled in the OEP. Instrumental activities of daily living and physical health scores (PHS) increased significantly with the OEP intervention (median PHS: visit 1, 55 [range, 0-100]; visit 2, 70 [range, 30-100]; P<.01). Patient-reported Karnofsky performance status increased significantly, and the improvement was sustained (median [range]: visit 1, 80 [40-100]; visit 3, 90 [50-100]; P=.05). Quality of life (Patient-Reported Outcome Measurement Information System [PROMIS]) improved significantly by the end of the 6-month period (median [range]: visit 1, 32.4 [19.9-47.7]; visit 3, 36.2 [19.9-47.7]; P=.01]. Enhanced measures of gait speed and balance, using the Short Physical Performance Battery scores, were associated with a 20% decrease in risk of death (hazard ratio, 0.80; 95% CI, 0.65-0.97; P=.03) and a shorter hospital length of stay (decrease of 1.29 days; 95% CI, -2.46 to -0.13; P=.03). Peripheral blood immunosenescent markers were analyzed in relationship to clinical frailty and reports of mPhenoAge epigenetic analysis are preliminarily reported. Chronologic age had no relationship to overall survival, length of stay, or emergency department utilization. CONCLUSIONS: The OEP was effective in improving quality of life, and geriatric tools predicted survival and hospital utilization among older adults with hematologic malignancies.

Lenalidomide and Vorinostat Maintenance after Autologous Transplantation in Multiple Myeloma: Long- Term Follow-Up.

Post-autologous stem cell transplantation (ASCT) maintenance therapy with lenalidomide is standard of care for patients with multiple myeloma (MM). Effective and tolerable drug combinations may further enhance the clinical response post-ASCT. Vorinostat, a histone deacetylase inhibitor, induces antiproliferative and proapoptotic effects in patients with MM. We hypothesized that combination maintenance therapy would further prolong the clinical response achieved from transplantation. We previously reported that the combination of lenalidomide and vorinostat as maintenance post-ASCT was tolerable in 16 patients with MM. We now present the long-term follow up of these patients. Progression-free survival (PFS) and overall survival (OS) outcomes were characterized using the Kaplan-Meier method. Five patients (31%) had high-risk disease, and the median number of lines of therapy before ASCT was 1 (range, 1 to 5). With a median follow-up of 89.8 months from ASCT, the median PFS was 64.3 months (range, 21.7 months to not reached [NR]), and OS was not reached (median, 53.0 months to NR). At the time of this report, 5 patients remained on the study. The combination of vorinostat and lenalidomide as maintenance post-ASCT is tolerable and induces a durable response. A phase III randomized study of lenalidomide versus a combination with vorinostat is warranted.

Long-Term Follow-up of CALGB (Alliance) 100001: Autologous Followed by Nonmyeloablative Allogeneic Transplant for Multiple Myeloma.

CALGB (Alliance) 100001 was a phase II study evaluating autologous stem cell transplant (ASCT) followed by nonmyeloablative allogeneic stem cell transplant (alloSCT) in patients with multiple myeloma who had received no more than 18 months of prior therapy and had experienced no more than 1 prior progression event. Conditioning for ASCT was with high-dose melphalan (200 mg/m2). The alloSCT reduced-intensity conditioning (RIC) regimen consisted of fludarabine (30 mg/m2/d i.v. on days -7 through -3) and cyclophosphamide (1 g/m2/d i.v. on days -4 through -3). The primary objective was to determine the 6-month post-alloSCT treatment-related mortality (TRM) rate. Additional objectives included determining the proportion of patients who could complete this tandem ASCT-alloSCT approach in a cooperative group setting, overall response rates, rates of donor chimerism, rates of graft-versus-host disease (GVHD), disease-free survival, and overall survival (OS). Sixty patients were enrolled, of whom 57 (95%) completed ASCT and 49 (82%) completed tandem ASCT-alloSCT. The TRM rate was 2% (1/49; 90% confidence interval, 0.10% to 9.3%). Moderate to severe (grades 2 to 3) acute GVHD was observed in 13 of 49 alloSCT patients (27%). One patient died due to GVHD within 9 months of alloSCT. Twenty-seven of the 49 patients (55%) who underwent alloSCT reported chronic GVHD as either limited (15/49; 31%) or extensive (12/49; 24%) in the first year post-alloSCT and prior to the start of nonprotocol therapy for progressive disease. With a median follow-up for survival of 11 years, the median OS time is 6.6 years and the median time to disease progression is 3.6 years. Similar to other studies, this study confirmed that tandem ASCT/alloSCT is associated with durable disease control in a subset of patients. This study demonstrated the feasibility of performing tandem ASCT/alloSCT in a cooperative group setting and determined that a fludarabine/cyclophosphamide RIC regimen is associated with a very low TRM rate.

T Cell Transcriptional Profiling and Immunophenotyping Uncover LAG3 as a Potential Significant Target of Immune Modulation in Multiple Myeloma.

Autologous stem cell transplant (ASCT) is the standard of care for patients with multiple myeloma (MM). The clinical significance of peripheral blood T lymphocyte (PBTL) immunologic changes associated with ASCT is poorly understood. Here we evaluated T cell transcriptional messenger RNA profiles and immunophenotypes to correlate immunologic senescence, exhaustion, and anergy with clinical endpoints in a cohort of patients with MM undergoing ASCT. ASCT induced global transcriptional T cell changes and altered molecular levels of markers of T cell subtypes, T cell activation, and exhaustion. These included reduced CD4/CD8 ratio, skewing toward the Th1 subset, reduced expression of costimulatory receptors CD27 and CD28, heightened T cell activation, and increased expression of immune modulatory molecules LAG3 and PD1. Multicolor flow cytometry experiments confirmed altered circulating CD4 and CD8 subsets and skewing toward differentiated effector cells. Moreover, ASCT promoted an exhausted immunophenotype in CD3+CD4+ subsets and a senescent immunophenotype in CD3+CD8+ subsets. Subset-specific altered expression was also seen for surface molecules with immunomodulatory function. ASCT affected soluble levels of molecules with immunomodulatory function by increasing plasma HVEM and TIM3. High molecular LAG3 level was associated with inferior event-free survival post-ASCT (hazard ratio = 5.44; confidence interval, 1.92 to 15.46; P = .001; adjusted P [controlling for false discovery rate] = .038). Using a comprehensive evaluation of PBTLs on a molecular and phenotypic level, we have identified that ASCT induces global T cell alterations with CD4 and CD8 subset-specific changes. Moreover, LAG3 emerged as an early biomarker of adverse events post-ASCT. These findings will support the development of treatment strategies targeting immune defects in MM to augment or restore T cell responses.

Human AML activates the aryl hydrocarbon receptor pathway to impair NK cell development and function.

Acute myeloid leukemia (AML) can evade the mouse and human innate immune system by suppressing natural killer (NK) cell development and NK cell function. This is driven in part by the overexpression of microRNA (miR)-29b in the NK cells of AML patients, but how this occurs is unknown. In the current study, we demonstrate that the transcription factor aryl hydrocarbon receptor (AHR) directly regulates miR-29b expression. We show that human AML blasts activate the AHR pathway and induce miR-29b expression in NK cells, thereby impairing NK cell maturation and NK cell function, which can be reversed by treating NK cells with an AHR antagonist. Finally, we show that inhibition of constitutive AHR activation in AML blasts lowers their threshold for apoptosis and decreases their resistance to NK cell cytotoxicity. Together, these results identify the AHR pathway as a molecular mechanism by which AML impairs NK cell development and function. The results lay the groundwork in establishing AHR antagonists as potential therapeutic agents for clinical development in the treatment of AML.

Comparison of Two Doses of Antithymocyte Globulin in Reduced-Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation.

The appropriate dose of antithymocyte globulin (ATG) to be used in reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (allo-HSCT) is yet to be determined. We retrospectively analyzed the outcomes of patients who underwent unrelated or mismatch related RIC allo-HSCT for hematologic malignancies and received r-ATG (4.5 mg/kg, 141 patients) versus R-ATG (6 mg/kg, 216 patients). There was a higher incidence of cytomegalovirus (P < .001) and Epstein-Barr virus viremia (P =.03) in the R-ATG group than in the r-ATG group. The cumulative incidences of acute graft-versus-host disease (aGVHD) grades II to IV at day 180 in the r-ATG and R-ATG groups were 59% and 44% (P = .006) and grades III to IV 20% and 12% (P = .029), respectively. In multivariable models adjusting for disease diagnosis, the risk of aGVHD grades III to IV did not reach statistical significance (P = .087). The respective cumulative incidences of chronic GVHD in the r-ATG and R-ATG groups were 26% and 15% (P = .10), respectively. There were no significant differences in relapse rate (P = .24), nonrelapse mortality (P = .96), progression-free survival (P = .24), overall survival (P = .70), and GVHD-free relapse-free survival (P = .24). In this retrospective analysis, aGVHD incidence was higher in those treated with r-ATG compared with R-ATG, but this did not translate into significant differences of clinical outcome. Given the increasing use of RIC allo-HSCT for treating malignant hematologic conditions, the correct dose and schedule of ATG administration should be defined by prospective randomized controlled trials.

BEAM versus BUCYVP16 Conditioning before Autologous Hematopoietic Stem Cell Transplant in Patients with Hodgkin Lymphoma.

High-dose chemotherapy followed by autologous hematopoietic stem cell transplant (AHSCT) is a standard of care for patients with relapsed Hodgkin lymphoma. Different conditioning regimens before AHSCT have been used, with the 2 most common being BEAM (carmustine, etoposide, cytarabine, and melphalan) and BUCYVP16 (busulfan, cyclophosphamide, and etoposide). We retrospectively compared the outcomes of patients treated with BEAM (n = 128) or BUCYVP16 (n = 105) followed by AHSCT. After a median follow-up of 4.2 years for BEAM and 3.8 for BUCYVP16 from AHSCT, the 5-year cumulative incidence of relapse was 29% with BEAM compared with 56% with BUCYVP16 (P < .001). Median progression free survival (PFS) and overall survival (OS) were not reached with BEAM and were 2.0 and 7.8 years with BUCYVP16, respectively. Improved PFS (P < .001) and OS (P = .001) were observed with BEAM for patients who needed transplant within 24 months from diagnosis and for patients not in complete remission (non-CR; P = .001 and P < .001, respectively) at AHSCT. In this large retrospective comparison the use of BEAM conditioning before AHSCT resulted in a statistically significant improved PFS and OS and lower relapse compared with BUCYVP16. This supports the use of BEAM as a frontline conditioning regimen before AHSCT for early relapsed and non-CR Hodgkin lymphoma.

A phase 1b study of isatuximab plus lenalidomide and dexamethasone for relapsed/refractory multiple myeloma.

This phase 1b, open-label, dose-escalation study assessed the safety, efficacy, and pharmacokinetics of anti-CD38 monoclonal antibody isatuximab given in 2 schedules (3, 5, or 10 mg/kg every other week [Q2W] or 10 or 20 mg/kg weekly [QW] for 4 weeks and then Q2W thereafter [QW/Q2W]), in combination with lenalidomide 25 mg (days 1-21) and dexamethasone 40 mg (QW), in patients with relapsed/refractory multiple myeloma (RRMM). Patients received 28-day treatment cycles; the primary objective was to determine the maximum tolerated dose (MTD) of isatuximab with lenalidomide and dexamethasone. Fifty-seven patients (median 5 [range 1-12] prior regimens; 83% refractory to previous lenalidomide therapy) were treated. Median duration of dosing was 36.4 weeks; 15 patients remained on treatment at data cutoff. Isatuximab-lenalidomide-dexamethasone was generally well tolerated with only 1 dose-limiting toxicity reported (grade 3 pneumonia at 20 mg/kg QW/Q2W); the MTD was not reached. The most common isatuximab-related adverse events were infusion-associated reactions (IARs) (56%), which were grade 1/2 in 84% of patients who had an IAR and predominantly occurred during the first infusion. In the efficacy-evaluable population, the overall response rate (ORR) was 56% (29/52) and was similar between the 10 mg/kg Q2W and 10 and 20 mg/kg QW/Q2W cohorts. The ORR was 52% in 42 evaluable lenalidomide-refractory patients. Overall median progression-free survival was 8.5 months. Isatuximab exposure increased in a greater than dose-proportional manner; isatuximab and lenalidomide pharmacokinetic parameters appeared independent. These data suggest that isatuximab combined with lenalidomide and dexamethasone is active and tolerated in heavily pretreated patients with RRMM. This trial was registered at www.clinicaltrials.gov as #NCT01749969.

Anti-leukemic effects of all-trans retinoic acid in combination with Daratumumab in acute myeloid leukemia.

Acute myeloid leukemia (AML) remains a significant health problem, with poor outcomes despite chemotherapy and bone marrow transplants. Although one form of AML, acute promyelocytic leukemia (APL), is successfully treated with all-trans retinoic acid (ATRA), this drug is seemingly ineffective against all other forms of AML. Here, we show that ATRA up-regulates CD38 expression on AML blasts to sufficient levels that promote antibody-mediated fratricide following the addition of anti-CD38 daratumumab (DARA). The combination of ATRA plus DARA induced Fc-dependent conjugate formation and cytotoxicity among AML blasts in vitro. Combination treatment also led to reduction in tumor volume and resulted in increased overall survival in murine engraftment models of AML. These results suggest that, although ATRA does not induce differentiation of non-APL, it may be effective as a therapy in conjunction with DARA.

Interferon-γ Promotes Antibody-mediated Fratricide of Acute Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is characterized by the proliferation of immature myeloid lineage blasts. Due to its heterogeneity and to the high rate of acquired drug resistance and relapse, new treatment strategies are needed. Here, we demonstrate that IFNγ promotes AML blasts to act as effector cells within the context of antibody therapy. Treatment with IFNγ drove AML blasts toward a more differentiated state, wherein they showed increased expression of the M1-related markers HLA-DR and CD86, as well as of FcγRI, which mediates effector responses to therapeutic antibodies. Importantly, IFNγ was able to up-regulate CD38, the target of the therapeutic antibody daratumumab. Because the antigen (CD38) and effector receptor (FcγRI) were both simultaneously up-regulated on the AML blasts, we tested whether IFNγ treatment of the AML cell lines THP-1 and MV4-11 could stimulate them to target one another after the addition of daratumumab. Results showed that IFNγ significantly increased daratumumab-mediated cytotoxicity, as measured both by 51Cr release and lactate dehydrogenase release assays. We also found that the combination of IFNγ and activation of FcγR led to the release of granzyme B by AML cells. Finally, using a murine NSG model of subcutaneous AML, we found that treatment with IFNγ plus daratumumab significantly attenuated tumor growth. Taken together, these studies show a novel mechanism of daratumumab-mediated killing and a possible new therapeutic strategy for AML.

Granulocyte Colony-Stimulating Factor-Mobilized Allografts Contain Activated Immune Cell Subsets Associated with Risk of Acute and Chronic Graft-versus-Host Disease.

We defined associations among immune cell subsets in granulocyte colony-stimulating factor (G-CSF)-mobilized allografts and clinical outcomes after allogeneic hematopoietic cell transplantation (alloHCT). Fresh peripheral blood stem cell (PBSC) aliquots from 238 G-CSF-mobilized allografts were extensively characterized by immunophenotype. Subset-specific transplanted cells were correlated with acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), malignant disease relapse, nonrelapse mortality, and overall survival. Of 238 assessable alloHCT recipients, 185 patients (78%) received reduced-intensity conditioning and 152 (64%) antithymocyte globulin-based serotherapy. Incidences of aGVHD and cGVHD were 58% and 48%, respectively. Median follow-up was 21 months (range, 1.4 to 41.1). In multivariable analyses adjusted for relevant clinical factors, allograft activated natural killer (NK) cells (CD56(+)CD16(+)CD69(+)CD158b(+)) were associated with a significantly lower risk of aGVHD (P = .0016; HR, .51; 95% confidence interval, .33 to .78), whereas late-activated HLA-DR(+) CD3(+) cells were associated with significantly higher aGVHD (P < .0005; HR, 2.31; 95% confidence interval, 1.55 to 3.43). In a subgroup of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), receipt of an allograft from an older donor (≥40 years) was associated with a higher incidence of relapse (P = .0042; HR, 2.99); allograft content of early activated CD3(+) cells (CD3(+)CD69(+); P = .0024; HR, .4) and NKT cells (CD3(+)CD56(+); P = .0006; HR, .54) were associated with a lower incidence of relapse. Presence of HLA-Bw4-80Ile(+) genotype was associated with lower relapse incidence. In conclusion, activated NK cells within PBSC allografts associate with lower aGVHD risk, whereas HLA-DR(+) T cells associate with higher aGVHD and cGVHD risk. NKT cells and early activated T cells are associated with lower relapse risk in AML and MDS patients. These findings may have implications in therapeutic targeting of select populations in the allograft to minimize incidence of GVHD.

Atorvastatin for the Prophylaxis of Acute Graft-versus-Host Disease in Patients Undergoing HLA-Matched Related Donor Allogeneic Hematopoietic Stem Cell Transplantation (allo-HCT).

Statins possess potent immunomodulatory effects that may play a role in preventing acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). We performed a phase II study of atorvastatin for aGVHD prophylaxis when given to allo-HCT recipients and their HLA-matched sibling donors. Atorvastatin (40 mg/day) was administered to sibling donors, beginning 14 days before the anticipated start of stem cell collection. Allo-HCT recipients (n = 40) received atorvastatin (40 mg/day) in addition to standard aGVHD prophylaxis. The primary endpoint was cumulative incidence of grades II to IV aGVHD at day 100. Atorvastatin was well tolerated, with no attributable grades III to IV toxicities in donors or their recipients. Day 100 and 180 cumulative incidences of grades II to IV aGVHD were 30% (95% confidence interval [CI], 17% to 45%) and 40% (95% CI, 25% to 55%), respectively. One-year cumulative incidence of chronic GVHD was 43% (95% CI, 32% to 69%). One-year nonrelapse mortality and relapse incidences were 5.5% (95% CI, .9% to 16.5%) and 38% (95% CI, 18% to 47%), respectively. One-year progression-free and overall survival rates were 54% (95% CI, 38% to 71%) and 82% (95% CI, 69% to 94%). One-year GVHD-free, relapse-free survival was 27% (95% CI, 16% to 47%). These results did not differ from our historical control subjects (n = 96). Although safe and tolerable, the addition of atorvastatin did not appear to provide any benefit to standard GVHD prophylaxis alone.

A phase 1 study of the PI3Kδ inhibitor idelalisib in patients with relapsed/refractory mantle cell lymphoma (MCL).

Idelalisib, an oral inhibitor of phosphatidylinositol-3-kinase δ (PI3Kδ), was evaluated in a 48-week phase 1 study (50-350 mg daily or twice daily) enrolling 40 patients with relapsed or refractory mantle cell lymphoma (MCL). Primary outcome was safety and dose-limiting toxicity (DLT). Secondary outcomes were pharmacokinetic parameters, pharmacodynamic effects, overall response rate (ORR), progression-free survival (PFS), and duration of response (DOR). Patients without DLT and no evidence of disease progression after 48 weeks enrolled in the extension study. Patients had median age of 69 years (range, 52-83) and received median of 4 prior therapies (1-14); 17 of 40 patients (43%) were refractory to their most recent treatment. Median duration of idelalisib treatment was 3.5 months (range, 0.7-30.7), with 6 (15%) continuing extension treatment. Common grade ≥3 adverse events (AEs) included (total%/grade ≥3%) diarrhea (40/18), nausea (33/5), pyrexia (28/0), fatigue (25/3), rash (23/3), decreased appetite (20/15), upper respiratory infection (20/0), pneumonia (13/10), and alanine transaminase or aspartate transaminase elevations (60/20). ORR was 16 of 40 patients (40%), with CR in 2 of 40 patients (5%). Median DOR was 2.7 months, median PFS was 3.7 months, and 1-year PFS was 22%. These data provide proof of concept that targeting PI3Kδ is a viable strategy and worthy of additional study in MCL. This trial was registered at www.clinicaltrials.gov as #NCT00710528.

Idelalisib, a selective inhibitor of phosphatidylinositol 3-kinase-δ, as therapy for previously treated indolent non-Hodgkin lymphoma.

Idelalisib (GS-1101, CAL-101), an oral inhibitor of phosphatidylinositol 3-kinase-δ, was evaluated in a phase I study in 64 patients with relapsed indolent non-Hodgkin lymphoma (iNHL). Patients had a median (range) age of 64 (32-91) years, 34 (53%) had bulky disease (≥1 lymph nodes ≥5 cm), and 37 (58%) had refractory disease. Patients had received a median (range) of 4 (1-10) prior therapies. Eight dose regimens of idelalisib were evaluated; idelalisib was taken once or twice daily continuously at doses ranging from 50 to 350 mg. After 48 weeks, patients still benefitting (n = 19; 30%) enrolled into an extension study. Adverse events (AEs) occurring in 20% or more patients (total%/grade ≥3%) included diarrhea (36/8), fatigue (36/3), nausea (25/3), rash (25/3), pyrexia (20/3), and chills (20/0). Laboratory abnormalities included neutropenia (44/23), anemia (31/5), thrombocytopenia (25/11), and serum transaminase elevations (48/25). Twelve (19%) patients discontinued therapy due to AEs. Idelalisib induced disease regression in 46/54 (85%) of evaluable patients achieving an overall response rate of 30/64 (47%), with 1 patient having a complete response (1.6%). Median duration of response was 18.4 months, median progression-free survival was 7.6 months. Idelalisib is well tolerated and active in heavily pretreated, relapsed/refractory patients with iNHL. These trials were registered at clinicaltrials.gov as NCT00710528 and NCT01090414.

Idelalisib, an inhibitor of phosphatidylinositol 3-kinase p110δ, for relapsed/refractory chronic lymphocytic leukemia.

In a phase 1 trial, idelalisib (GS-1101, CAL-101), a selective inhibitor of the lipid kinase PI3Kδ, was evaluated in 54 patients with relapsed/refractory chronic lymphocytic leukemia (CLL) with adverse characteristics including bulky lymphadenopathy (80%), extensive prior therapy (median 5 [range 2-14] prior regimens), treatment-refractory disease (70%), unmutated IGHV (91%), and del17p and/or TP53 mutations (24%). Patients were treated at 6 dose levels of oral idelalisib (range 50-350 mg once or twice daily) and remained on continuous therapy while deriving clinical benefit. Idelalisib-mediated inhibition of PI3Kδ led to abrogation of Akt phosphorylation in patient CLL cells and significantly reduced serum levels of CLL-related chemokines. The most commonly observed grade ≥3 adverse events were pneumonia (20%), neutropenic fever (11%), and diarrhea (6%). Idelalisib treatment resulted in nodal responses in 81% of patients. The overall response rate was 72%, with 39% of patients meeting the criteria for partial response per IWCLL 2008 and 33% meeting the recently updated criteria of PR with treatment-induced lymphocytosis.(1,2) The median progression-free survival for all patients was 15.8 months. This study demonstrates the clinical utility of inhibiting the PI3Kδ pathway with idelalisib. Our findings support the further development of idelalisib in patients with CLL. These trials were registered at clinicaltrials.gov as #NCT00710528 and #NCT01090414.

Lenalidomide and vorinostat maintenance after autologous transplant in multiple myeloma.

UNLABELLED: Single-agent post-autologous transplant maintenance therapy with lenalidomide is standard of care for patients with multiple myeloma. The tolerability and effectiveness of combination post-transplant maintenance therapy is unknown, so we investigated lenalidomide and vorinostat (suberoylanilide hydroxamic acid) in this setting, hypothesizing that the regimen would be well tolerated and associated with an improved post-transplant response. This trial followed a standard 3 × 3 dose escalation phase 1 design. Vorinostat was administered beginning day +90 post-haematopoietic stem cell transplantation for days 1-7 and 15-21, and lenalidomide was started at 10 mg days 1-21, both on a 28-d cycle. The primary endpoint was maximum tolerated dose and dose limiting toxicities were assessed during the first cycle. Treatment was well tolerated in 16 enrolled patients. During Cycle 1, the most common toxicities included cytopenias, gastrointestinal complaints and fatigue. Seven patients improved their transplant response after starting combination therapy. The median follow-up was 38·4 months, and the median progression-free survival and overall survival have yet to be reached. This oral post-transplant maintenance regimen was well tolerated. This is the first trial to publish results on the use of a histone deacetylase inhibitor in the maintenance setting, and it provides rationale for the ongoing randomized trial in maintenance (ISRCTN 49407852). TRIAL REGISTRATION: NCT00729118.

The combination of milatuzumab, a humanized anti-CD74 antibody, and veltuzumab, a humanized anti-CD20 antibody, demonstrates activity in patients with relapsed and refractory B-cell non-Hodgkin lymphoma.

As a result of the anti-tumour activity observed in vitro and in vivo with combined anti-CD20 and anti-CD74 antibodies, we initiated a phase I/II trial of veltuzumab and milatuzumab in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (NHL). Patients received an induction of veltuzumab 200 mg/m(2) weekly combined with escalating doses of milatuzumab at 8, 16 and 20 mg/kg weekly for 4 weeks. Patients without disease progression could receive an extended induction with treatment on weeks 12, 20, 28 and 36. A total of 35 patients enrolled on the study. Median age was 63 years, median number of prior therapies was 3, and 63% of patients were rituximab refractory. No dose-limiting toxicities were observed in the phase I study. Related grade 3-4 toxicities included lymphopenia, leucopenia, neutropenia, anaemia, infusion reactions, hyperglycaemia, fatigue and atrial tachycardia. Median weeks of therapy was 12 and 29% of patients completed all 36 weeks of therapy. The overall response rate was 24%, median duration of response was 12 months, and responses were observed at all dose levels and in 50% of patients refractory to rituximab. Combination therapy with veltuzumab and milatuzumab demonstrated activity in a population of heavily pre-treated patients with relapsed or refractory indolent NHL.

Can NKT cells extinguish smoldering myeloma?

One of the greatest challenges in all of medicine is to improve on the life of an asymptomatic patient; however, in this issue of Blood, Richter and colleagues share provocative new data taking steps toward accomplishing this goal.