Prognostic or predictive value of circulating cytokines and angiogenic factors for initial treatment of multiple myeloma in the GIMEMA MM0305 randomized controlled trial.

BACKGROUND: Several new drugs are approved for treatment of patients with multiple myeloma (MM), but no validated biomarkers are available for the prediction of a clinical outcome. We aimed to establish whether pretreatment blood and bone marrow plasma concentrations of major cytokines and angiogenic factors (CAFs) of patients from a phase 3 trial of a MM treatment could have a prognostic and predictive value in terms of response to therapy and progression-free and overall survival and whether these patients could be stratified for their prognosis. METHODS: Blood and bone marrow plasma levels of Ang-2, FGF-2, HGF, VEGF, PDGF-ß, IL-8, TNF-α, TIMP-1, and TIMP-2 were determined at diagnosis in MM patients enrolled in the GIMEMA MM0305 randomized controlled trial by an enzyme-linked immunosorbent assay (ELISA). These levels were correlated both reciprocally and with the type of therapy and patients' characteristics and with a group of non-MM patients as controls. RESULTS: No significant differences were detected between the blood and bone marrow plasma levels of angiogenic cytokines. A cutoff for each CAF was established. The therapeutic response of patients with blood plasma levels of CAFs lower than the cutoff was better than the response of those with higher levels in terms of percentage of responding patients and quality of response. CONCLUSION: FGF-2, HGF, VEGF, and PDGF-ß plasma levels at diagnosis have predictive significance for response to treatment. The stratification of patients based on the levels of CAFs at diagnosis and their variations after therapy is useful to characterize different risk groups concerning outcome and response to therapy. TRIAL REGISTRATION: Clinical trial information can be found at the following link: NCT01063179.

Continuous therapy in standard- and high-risk newly-diagnosed multiple myeloma: A pooled analysis of 2 phase III trials.

BACKGROUND: Risk-adapted therapy is a common strategy in curable hematologic malignancies: standard-risk patients receive less intensive treatment, whereas high-risk patients require a more intensive approach. This model cannot be applied in multiple myeloma (MM), which is still incurable. Continuous treatment (CT) is a key strategy for MM treatment, since it improves duration of remission. However, the role of CT according to standard- or high-risk baseline prognosis remains an open question. PATIENTS AND METHODS: We performed a pooled analysis of 2 phase III trials (GIMEMA-MM-03-05 and RV-MM-PI-209) that randomized patients to CT vs fixed-duration therapy (FDT). RESULTS: In the overall patient population (n = 550), CT improved progression-free survival1 (PFS1) (HR 0.54), PFS2 (HR 0.61) and overall survival (OS) (HR 0.71) vs FDT. CT improved PFS1 both in R-ISS I (HR 0.49) and R-ISS II/III patients (HR 0.55). Four-year PFS1 was 38% in R-ISS II/III patients receiving CT and 25% in R-ISS I patients receiving FDT, with similar trends for PFS2 and OS. High-risk patients benefited more from proteasome-inhibitor plus immunomodulatory-based CT than immunomodulatory alone. CONCLUSION: Good prognosis patients receiving FDT lose their prognostic advantage over high-risk patients receiving CT and high-risk patients may benefit from more intensive maintenance including proteasome inhibitors and immunomodulators.

Treatment Intensification With Autologous Stem Cell Transplantation and Lenalidomide Maintenance Improves Survival Outcomes of Patients With Newly Diagnosed Multiple Myeloma in Complete Response.

BACKGROUND: High-dose therapy with autologous stem cell transplantation (HDT-ASCT) and maintenance treatment with novel agents are the best options for patients with newly diagnosed multiple myeloma, increasing the rate of complete response (CR) and prolonging progression-free survival (PFS) and overall survival (OS). Indeed, the achievement of a CR is a predictor of long-term survival among transplant-eligible patients. However, it is unclear whether patients reaching a CR after induction treatment could receive less intense consolidation or avoid maintenance therapy. PATIENTS AND METHODS: We analyzed CR patients treated in 2 phase III trials, GIMEMA-RV-MM-PI-209 and RV-MM-EMN-441, to compare HDT-ASCT with an R-Alk (lenalidomide, alkylator) regimen as consolidation, and lenalidomide (R) maintenance with no maintenance. The primary endpoints were PFS, second PFS (PFS2), and OS from consolidation and maintenance (_m). RESULTS: Overall, the data from 166 patients in CR were analyzed, 95 in the HDT-ASCT group and 71 in the R-Alk group. The CR patients who received HDT-ASCT had a better PFS (hazard ratio [HR], 0.55; P = .01), PFS2 (HR, 0.46; P = .02), and OS (HR, 0.42; P = .03) compared with patients randomized to R-Alk. The survival benefit with HDT-ASCT was confirmed among all the subgroups, according to age, International Staging System (ISS stage, cytogenetic profile, and receipt of maintenance therapy. CR patients who received lenalidomide maintenance had a better PFS_m (4 years: 54% vs. 19%; HR, 0.43; P = .02) compared with those who received no maintenance. However, no difference was observed in terms of PFS2_m (4 years: 72% vs. 58%; HR, 0.83; P = .67) and OS_m (4 years: 79% vs. 72%; HR, 0.82; P = .73) with maintenance therapy. CONCLUSION: Even in CR patients, outcomes were improved by an intensified approach with HDT-ASCT consolidation and lenalidomide-based maintenance therapy.

Maintenance in myeloma patients achieving complete response after upfront therapy: a pooled analysis.

PURPOSE: Maintenance demonstrated to improve survival in newly diagnosed multiple myeloma (NDMM) patients and the achievement of complete response (CR) is a strong predictor of survival. Nevertheless, the role of maintenance according to response after induction/consolidation has not been investigated so far. To evaluate the impact of maintenance according to response, we pooled together and retrospectively analyzed data from 955 NDMM patients enrolled in two trials (GIMEMA-MM-03-05 and RV-MM-PI-209). METHODS: Primary endpoints were progression-free survival (PFS)1, PFS2 and overall survival (OS) of CR patients randomized to maintenance and no maintenance. Secondary endpoints were PFS1, PFS2 and OS in very good partial response/partial response (VGPR/PR) patients. RESULTS: Overall, 213 patients obtained CR after induction/consolidation, 118 received maintenance and 95 no maintenance. In patients achieving CR, maintenance significantly improved PFS1 (HR 0.50, P < 0.001), PFS2 (HR 0.58, P 0.02) and OS (HR 0.51, P 0.02) compared with no maintenance; the advantage was maintained across all the analyzed subgroups according to age, International Staging System (ISS) stage, cytogenetic profile and treatment. Similar features were seen in VGPR/PR patients. CONCLUSION: Maintenance prolonged survival in CR and in VGPR/PR patients. The benefit in CR patients suggests the importance of continuing treatment in patients with chemo-sensitive disease. TRIAL REGISTRATION: The two source studies are registered at ClinicalTrials.gov: identification numbers NCT01063179 and NCT00551928.

Triplet vs doublet lenalidomide-containing regimens for the treatment of elderly patients with newly diagnosed multiple myeloma.

Lenalidomide-dexamethasone improved outcome in newly diagnosed elderly multiple myeloma patients. We randomly assigned 662 patients who were age ≥65 years or transplantation-ineligible to receive induction with melphalan-prednisone-lenalidomide (MPR) or cyclophosphamide-prednisone-lenalidomide (CPR) or lenalidomide plus low-dose dexamethasone (Rd). The primary end point was progression-free survival (PFS) in triplet (MPR and CPR) vs doublet (Rd) lenalidomide-containing regimens. After a median follow-up of 39 months, the median PFS was 22 months for the triplet combinations and 21 months for the doublet (P = .284). The median overall survival (OS) was not reached in either arms, and the 4-year OS was 67% for the triplet and 58% for the doublet arms (P = .709). By considering the 3 treatment arms separately, no difference in outcome was detected among MPR, CPR, and Rd. The most common grade ≥3 toxicity was neutropenia: 64% in MPR, 29% in CPR, and 25% in Rd patients (P < .0001). Grade ≥3 nonhematologic toxicities were similar among arms and were mainly infections (6.5% to 11%), constitutional (3.5% to 9.5%), and cardiac (4.5% to 6%), with no difference among the arms. In conclusion, in the overall population, the alkylator-containing triplets MPR and CPR were not superior to the alkylator-free doublet Rd, which was associated with lower toxicity. This study was registered at www.clinicaltrials.gov as #NCT01093196.

Continuous Therapy Versus Fixed Duration of Therapy in Patients With Newly Diagnosed Multiple Myeloma.

PURPOSE: Continuous therapy (CT) prolongs progression-free survival 1 (PFS1; time from random assignment until the first progression or death), but chemotherapy-resistant relapse may negatively impact overall survival (OS). Progression-free survival 2 (PFS2; time from random assignment until the second progression or death) may represent an additional tool to estimate outcome. This study evaluates the benefit of novel agent-based CT versus fixed duration of therapy (FDT) in patients with newly diagnosed myeloma. METHODS: We included patients enrolled onto three phase III trials that randomly assigned patients to novel agent-based CT versus FDT. Primary analyses were restricted to the intent-to-treat population eligible for CT (patients progression free and alive at 1 year after random assignment). Primary end points were PFS1, PFS2, and OS. All hazard ratios (HRs) and 95% CIs were adjusted for several potential confounders using Cox models. RESULTS: In the pooled analysis of the three trials, 604 patients were randomly assigned to CT and 614 were assigned to FDT. Median follow-up was 52 months. In the intent-to-treat CT population, CT (n = 417), compared with FDT (n = 410), significantly improved PFS1 (median, 32 v 16 months, respectively; HR, 0.47; 95% CI, 0.40 to 0.56; P < .001), PFS2 (median, 55 v 40 months, respectively; HR, 0.61; 95% CI, 0.50 to 0.75; P < .001), and OS (4-year OS, 69% v 60%, respectively; HR, 0.69; 95% CI, 0.54 to 0.88; P = .003). CONCLUSION: In this pooled analysis, CT significantly improved PFS1, PFS2, and OS. The improvement in PFS2 suggests that the benefit reported during first remission is not cancelled by a shorter second remission. PFS2 is a valuable end point to estimate long-term clinical benefit and should be included in future trials.

mTOR pathway activation in multiple myeloma cell lines and primary tumour cells: pomalidomide enhances cytoplasmic-nuclear shuttling of mTOR protein.

mTOR is a protein kinase that plays a central role in regulating critical cellular processes. We evaluated the activation and cellular localization of the mTOR pathway in multiple myeloma (MM) and analyzed the role of pomalidomide in regulating mTOR. By immunohistochemistry cytoplasmic p-mTOR stained positive in 57 out 101 (57.6%) cases with a nuclear p-mTOR localization in 14 out 101 samples (13.8%). In the 70 MM samples analyzed for the entire pathway, p-mTOR expression significantly correlated with p-AKT, p-P70S6K, and p-4E-BP1 suggesting that the AKT/mTOR pathway is activated in a subset of MM patients. Immunofluorescence assays demonstrated that mTOR protein is distributed throughout the cytoplasm and the nucleus at baseline in MM cell lines and in plasma cells of 13 MM patients and that pomalidomide facilitated the shift of the mTOR protein in the nucleus. By western blotting, treatment with pomalidomide increased nuclear mTOR and p-mTOR expression levels in the nucleus with a concomitant decrease of the cytoplasmic fractions while does not seem to affect significantly AKT phosphorylation status. In MM cells the anti-myeloma activity of pomalidomide may be mediated by the regulation of the mTOR pathway.

Multiple myeloma: is a shift toward continuous therapy needed to move forward?

Multiple myeloma (MM) accounts for 1% of all cancers and 13% of all hematologic malignancies. Melphalan-prednisone plus melphalan-prednisone-thalidomide or melphalan-prednisone-bortezomib are considered the standards of care for newly diagnosed, transplant-ineligible patients with MM (older than 65 years). In newly diagnosed, transplant-eligible patients with MM (younger than 65 years), a novel agent-based induction followed by high-dose therapy and autologous stem cell transplantation, is the standard approach. The availability of novel agents has considerably increased the treatment options of this disease, but almost all patients relapse after achieving a maximal response to first-line therapy. New drugs and new treatment approaches are urgently needed to improve outcome in MM patients Continuous therapy can be a valid option to keep the patient symptom-free and to prolong progression-free survival and overall survival.

Bortezomib-melphalan-prednisone-thalidomide followed by maintenance with bortezomib-thalidomide compared with bortezomib-melphalan-prednisone for initial treatment of multiple myeloma: updated follow-up and improved survival.

PURPOSE: Bortezomib-melphalan-prednisone (VMP) has improved overall survival in multiple myeloma. This randomized trial compared VMP plus thalidomide (VMPT) induction followed by bortezomib-thalidomide maintenance (VMPT-VT) with VMP in patients with newly diagnosed multiple myeloma. PATIENTS AND METHODS: We randomly assigned 511 patients who were not eligible for transplantation to receive VMPT-VT (nine 5-week cycles of VMPT followed by 2 years of VT maintenance) or VMP (nine 5-week cycles without maintenance). RESULTS: In the initial analysis with a median follow-up of 23 months, VMPT-VT improved complete response rate from 24% to 38% and 3-year progression-free-survival (PFS) from 41% to 56% compared with VMP. In this analysis, median follow-up was 54 months. The median PFS was significantly longer with VMPT-VT (35.3 months) than with VMP (24.8 months; hazard ratio [HR], 0.58; P < .001). The time to next therapy was 46.6 months in the VMPT-VT group and 27.8 months in the VMP group (HR, 0.52; P < .001). The 5-year overall survival (OS) was greater with VMPT-VT (61%) than with VMP (51%; HR, 0.70; P = .01). Survival from relapse was identical in both groups (HR, 0.92; P = .63). In the VMPT-VT group, the most frequent grade 3 to 4 adverse events included neutropenia (38%), thrombocytopenia (22%), peripheral neuropathy (11%), and cardiologic events (11%). All of these, except for thrombocytopenia, were significantly more frequent in the VMPT-VT patients. CONCLUSION: Bortezomib and thalidomide significantly improved OS in multiple myeloma patients not eligible for transplantation.

Incorporating novel agents in the management of elderly myeloma patients.

In recent years, the treatment of multiple myeloma has undergone significant changes. The availability of novel agents bortezomib, thalidomide and lenalidomide considerably improved the outcome of patients. The advantages related to the use of novel agents have been shown in various studies in patients eligible and ineligible for transplant. In elderly patients, novel agents have also revolutionized the treatment paradigm and have replaced the traditional melphalan-prednisone regimen. A sequential approach consisting of an induction regimen associated with a high rate of complete response, followed by consolidation/maintenance therapy, induces a profound cytoreduction and delays relapse, thus improving survival. Patients older than 75 years or who are otherwise vulnerable are more susceptible to adverse events. In this setting, less toxic regimens and appropriate dose-reductions should be adopted. This article provides an overview of the main trials for transplant-ineligible multiple myeloma patients. Recommendations on how to manage unfit patients and treatment-related toxicities are also provided.

Pomalidomide, cyclophosphamide, and prednisone for relapsed/refractory multiple myeloma: a multicenter phase 1/2 open-label study.

We performed a phase 1/2 trial to determine the maximum tolerated dose (MTD) of pomalidomide and to explore its efficacy when combined with cyclophosphamide-prednisone in relapsed/refractory myeloma patients. Pomalidomide was given at 1 to 2.5 mg/d, cyclophosphamide at 50 mg every other day, prednisone at 50 mg every other day, for 6 28-day cycles, followed by pomalidomide-prednisone maintenance therapy. Thromboprophylaxis was recommended. Sixty-nine patients were enrolled, 55 received the MTD (2.5 mg/d) and were evaluated. Best responses included complete response in 3 patients (5%), very good partial response in 10 (18%), partial response in 15 (27%), minimal response in 11 (20%), stable disease in 15 (27%), and progressive disease in 1 (3%), for an overall response rate of 51%. The median time-to-response was 1.83 months. After a median follow-up of 14.8 months, median progression-free survival was 10.4 months and 1-year overall survival was 69%. At the MTD, grade 3 to 4 toxicities included anemia (9%), thrombocytopenia (11%), neutropenia (42%), neurologic events (7%), dermatologic events (7%), and thromboembolism (2%). Grade 3 to 5 infections occurred in 5 patients (9%). Five patients (9%) discontinued treatment for toxicity. New grade 3 to 4 adverse events were low during maintenance. Pomalidomide-cyclophosphamide-prednisone is safe and effective in relapsed/refractory myeloma patients. This trial was registered at www.clinicaltrials.gov as #NCT01166113.

Bortezomib induction, reduced-intensity transplantation, and lenalidomide consolidation-maintenance for myeloma: updated results.

A sequential approach including bortezomib induction, intermediate-dose melphalan, and autologous stem cell transplantation (ASCT), followed by lenalidomide consolidation-maintenance, has been evaluated. Efficacy and safety data have been analyzed on intention-to-treat and results updated. Newly diagnosed myeloma patients 65 to 75 years of age (n = 102) received 4 cycles of bortezomib-pegylated liposomal doxorubicin-dexamethasone, tandem melphalan (100 mg/m(2)) followed by ASCT (MEL100-ASCT), 4 cycles of lenalidomide-prednisone consolidation (LP), and lenalidomide maintenance (L) until disease progression. The complete response (CR) rate was 33% after MEL100-ASCT, 48% after LP and 53% after L maintenance. After a median follow-up of 66 months, median time-to-progression (TTP) was 55 months and median progression-free survival 48 months. Median overall survival (OS) was not reached, 5-year OS was 63%. In CR patients, median TTP was 70 months and 5-year OS was 83%. Median survival from relapse was 28 months. Death related to adverse events (AEs) occurred in 8/102 patients during induction or transplantation. Rate of death related to AEs was higher in patients ≥70 years compared with younger (5/26 vs 3/76, P = .024). Bortezomib-induction followed by ASCT and lenalidomide consolidation-maintenance is a valuable option for elderly myeloma patients, with the greatest benefit in those younger than 70 years of age.

Update on the use of defibrotide.

INTRODUCTION: Defibrotide is a polydisperse oligonucleotide obtained from porcine intestinal mucosa and prepared by controlled depolymerization of DNA. It is a nucleic acid polymer, predominantly single-stranded, which has anti-ischemic and anti-thrombotic properties. AREAS COVERED: The efficacy and safety of defibrotide in the treatment of veno-occlusive disease (VOD) occurring after high-dose chemotherapy and hematopoietic stem-cell transplantation is now well established in Phase II - III trials. A recent randomized, Phase III trial in pediatric patients has also demonstrated its role in the prevention of VOD. Preclinical studies reported the inhibitory effects of defibrotide on myeloma cells' growth through an antiangiogenic action and a regulation of the tumor-microenvironment interactions. A recent Phase II trial underlines the efficacy and safety of defibrotide-thalidomide-melphalan combination in the treatment of relapsed/refractory multiple myeloma. EXPERT OPINION: Defibrotide may be effective in the prophylaxis and the treatment of veno-occlusive disease. Recent experimental results suggest that defibrotide may belong to the new generation of anti-cancer drugs that can prevent tumor angiogenesis. In multiple myeloma, defibrotide may overcome the prothrombotic effect of thalidomide on endothelial cells. Further preclinical and clinical investigations are needed to assess the precise role of defibrotide in the treatment of patients with multiple myeloma.

Safety and efficacy of bortezomib-melphalan-prednisone-thalidomide followed by bortezomib-thalidomide maintenance (VMPT-VT) versus bortezomib-melphalan-prednisone (VMP) in untreated multiple myeloma patients with renal impairment.

We assessed efficacy, safety, and reversal of renal impairment (RI) in untreated patients with multiple myeloma given bortezomib-melphalan-prednisone-thalidomide followed by bortezomib-thalidomide (VMPT-VT) maintenance or bortezomib-melphalan-prednisone (VMP). Exclusion criteria included serum creatinine ≥ 2.5 mg/dL. In the VMPT-VT/VMP arms, severe RI (estimated glomerular filtration rate [eGFR] ≤ 30 mL/min), moderate RI (eGFR 31-50 mL/min), and normal renal function (eGFR > 50 mL/min), were 6%/7.9%, 24.1%/24.9%, and 69.8%/67.2%, respectively. Statistically significant improvements in overall response rates and progression-free survival were observed in VMPT-VT versus VMP arms across renal cohorts, except in severe RI patients. In the VMPT group, severe RI reduced overall survival (OS). RI was reversed in 16/63 (25.4%) patients receiving VMPT-VT versus 31/77 (40.3%) receiving VMP. Multivariate analysis showed male sex (P = .022) and moderate RI (P = .003) significantly predicted RI recovery. VMP patients achieving renal response showed longer OS. In both arms, greater rates of severe hematologic adverse events were associated with RI (eGFR < 50 mL/min), however, therapy discontinuation rates were unaffected. VMPT-VT was superior to VMP for cases with normal renal function and moderate RI, whereas VMPT-VT failed to outperform VMP in patients with severe RI, although the relatively low number of cases analyzed preclude drawing definitive conclusions. VMPT-VT had no advantage in terms of RI reversal over VMP.

Lenalidomide can induce long-term responses in patients with multiple myeloma relapsing after multiple chemotherapy lines, in particular after allogeneic transplant.

Evidence of long-term response to lenalidomide in heavily pretreated patients with multiple myeloma is lacking. This study sought to assess whether long-term responders exist, long-term responders' characteristics, and predictive factors of a long-term response. One hundred and four patients with multiple myeloma treated with lenalidomide and dexamethasone after ≥2 therapy lines (median, 3) were analyzed. Long-term response was defined as at least a partial response (≥PR) lasting ≥12 months. The overall response rate was 73%, and 80.3% of the responses were achieved within 5 months. The median response was 14.3 months. Patients evaluable for long-term response numbered 87, and a total of 47% were long-term responders. Compared to non-long-term responders, long-term responders had better overall survival, less light-chain multiple myeloma, and higher incidence of t(11;14). Previous allogeneic transplant (alloSCT) and the response quality predicted a long-term response. In conclusion, patients treated with lenalidomide can become long-term responders; alloSCT and response quality predict long-term response.

Bortezomib-melphalan-prednisone-thalidomide followed by maintenance with bortezomib-thalidomide compared with bortezomib-melphalan-prednisone for initial treatment of multiple myeloma: a randomized controlled trial.

PURPOSE: The combination of bortezomib-melphalan-prednisone (VMP) is a new standard of care for newly diagnosed multiple myeloma. This phase III study examined the efficacy of the four-drug combination of bortezomib-melphalan-prednisone-thalidomide (VMPT) followed by maintenance with bortezomib-thalidomide (VMPT-VT) compared with VMP treatment alone in untreated multiple myeloma patients who are ineligible for autologous stem-cell transplantation. PATIENTS AND METHODS: A total of 511 patients were randomly assigned to receive nine cycles of VMPT followed by continuous VT as maintenance, or nine cycles of VMP at the same doses with no additional therapy. The primary end point was progression-free survival. RESULTS: The 3-year estimates of progression-free survival were 56% in patients receiving VMPT-VT and 41% in those receiving VMP (hazard ratio [HR], 0.67; 95% CI, 0.50 to 0.90; P = .008). At 3 years, the cumulative proportions of patients who did not go on to the next therapy were 72% with VMPT-VT and 60% with VMP (HR, 0.58; 95% CI, 0.50 to 0.90; P = .007). Complete response rates were 38% in the VMPT-VT group and 24% in the VMP group (P < .001). The 3-year overall survival was 89% with VMPT-VT and 87% with VMP (HR, 0.92; 95% CI, 0.53 to 1.60; P = .77). Grade 3 to 4 neutropenia (38% v 28%; P = .02), cardiologic events (10% v 5%; P = .04), and thromboembolic events (5% v 2%; P = .08) were more frequent among patients assigned to the VMPT-VT group than among those assigned to the VMP group; treatment-related deaths were 4% with VMPT-VT and 3% with VMP. CONCLUSION: VMPT followed by VT as maintenance was superior to VMP alone in patients with multiple myeloma who are ineligible for autologous stem-cell transplantation.

Efficacy and safety of once-weekly bortezomib in multiple myeloma patients.

In a recent phase 3 trial, bortezomib-melphalan-prednisone-thalidomide followed by maintenance treatment with bortezomib-thalidomide demonstrated superior efficacy compared with bortezomib-melphalan-prednisone. To decrease neurologic toxicities, the protocol was amended and patients in both arms received once-weekly instead of the initial twice-weekly bortezomib infusions: 372 patients received once-weekly and 139 twice-weekly bortezomib. In this post-hoc analysis we assessed the impact of the schedule change on clinical outcomes and safety. Long-term outcomes appeared similar: 3-year progression-free survival rate was 50% in the once-weekly and 47% in the twice-weekly group (P > .999), and 3-year overall survival rate was 88% and 89%, respectively (P = .54). The complete response rate was 30% in the once-weekly and 35% in the twice-weekly group (P = .27). Nonhematologic grade 3/4 adverse events were reported in 35% of once-weekly patients and 51% of twice-weekly patients (P = .003). The incidence of grade 3/4 peripheral neuropathy was 8% in the once-weekly and 28% in the twice-weekly group (P < .001); 5% of patients in the once-weekly and 15% in the twice-weekly group discontinued therapy because of peripheral neuropathy (P < .001). This improvement in safety did not appear to affect efficacy. This study is registered at http://www.clinicaltrials.gov as NCT01063179.

Targeting TORC2 in multiple myeloma with a new mTOR kinase inhibitor.

Although preclinical work with rapalogs suggests potential in treatment of multiple myeloma (MM), they have been less successful clinically. These drugs allostearically inhibit the mammalian target of rapamycin kinase primarily curtailing activity of the target of rapamycin complex (TORC)1. To assess if the mammalian target of rapamycin within the TORC2 complex could be a better target in MM, we tested a new agent, pp242, which prevents activation of TORC2 as well as TORC1. Although comparable to rapamycin against phosphorylation of the TORC1 substrates p70S6kinase and 4E-BP-1, pp242 could also inhibit phosphorylation of AKT on serine 473, a TORC2 substrate, while rapamycin was ineffective. pp242 was also more effective than rapamycin in achieving cytoreduction and apoptosis in MM cells. In addition, pp242 was an effective agent against primary MM cells in vitro and growth of 8226 cells in mice. Knockdown of the TORC2 complex protein, rictor, was deleterious to MM cells further supporting TORC2 as the critical target for pp242. TORC2 activation was frequently identified in primary specimens by immunostaining for AKT phosphorylation on serine 473. Potential mechanisms of up-regulated TORC2 activity in MM were stimulation with interleukin-6 or insulin-like growth factor 1, and phosphatase and tensin homolog or RAS alterations. Combining pp242 with bortezomib led to synergistic anti-MM effects. These results support TORC2 as a therapeutic target in MM.