Melphalan and Exportin 1 Inhibitors Exert Synergistic Antitumor Effects in Preclinical Models of Human Multiple Myeloma.

High-dose chemotherapy with melphalan followed by autologous transplantation is a first-line treatment for multiple myeloma. Here, we present preclinical evidence that this treatment may be significantly improved by the addition of exportin 1 inhibitors (XPO1i). The XPO1i selinexor, eltanexor, and KOS-2464 sensitized human multiple myeloma cells to melphalan. Human 8226 and U266 multiple myeloma cell lines and melphalan-resistant cell lines (8226-LR5 and U266-LR6) were highly sensitized to melphalan by XPO1i. Multiple myeloma cells from newly diagnosed and relapsed/refractory multiple myeloma patients were also sensitized by XPO1i to melphalan. In NOD/SCIDγ mice challenged with either parental 8226 or U266 multiple myeloma and melphalan-resistant multiple myeloma tumors, XPO1i/melphalan combination treatments demonstrated stronger synergistic antitumor effects than single-agent melphalan with minimal toxicity. Synergistic cell death resulted from increased XPO1i/melphalan-induced DNA damage in a dose-dependent manner and decreased DNA repair. In addition, repair of melphalan-induced DNA damage was inhibited by selinexor, which decreased melphalan-induced monoubiquitination of FANCD2 in multiple myeloma cells. Knockdown of FANCD2 was found to replicate the effect of selinexor when used with melphalan, increasing DNA damage (γH2AX) by inhibiting DNA repair. Thus, combination therapies that include selinexor or eltanexor with melphalan may have the potential to improve treatment outcomes of multiple myeloma in melphalan-resistant and newly diagnosed patients. The combination of selinexor and melphalan is currently being investigated in the context of high-dose chemotherapy and autologous transplant (NCT02780609). SIGNIFICANCE: Inhibition of exportin 1 with selinexor synergistically sensitizes human multiple myeloma to melphalan by inhibiting Fanconi anemia pathway-mediated DNA repair.

Phase I Clinical Trial of Selinexor in Combination with Daunorubicin and Cytarabine in Previously Untreated Poor-Risk Acute Myeloid Leukemia.

PURPOSE: Induction chemotherapy results in complete remission (CR) rates of 20% to 50% among patients with poor-risk AML. Selinexor is an oral selective inhibitor of nuclear export with promising single-agent activity. By inhibiting the primary export protein, XPO1, selinexor localizes and activates tumor suppressor proteins in the nucleus and inhibits DNA damage repair, rationalizing combination with DNA-damaging agents. PATIENTS AND METHODS: This was a single-arm phase I clinical trial of selinexor combined with cytarabine and daunorubicin (7+3). Dose escalation was selinexor alone (3+3) with an expansion at the MTD. Cohorts 1 and 2 received 60 and 80 mg orally, respectively, twice weekly during induction. Consolidation cycles (≤ 2) with selinexor at induction dose plus 5+2 were allowed for patients who achieved CR. MTD and recommended phase II dose of selinexor were the primary endpoints. RESULTS: Twenty-one patients with poor-risk AML were enrolled. All 21 patients were included in the safety evaluations and survival analyses (4 in each of 2 cohorts; 13 in the expansion); 8 (53%) of the 19 patients evaluable for response achieved CR/CRi. MTD was not reached. Selinexor 80 mg (orally, twice weekly) was used in the expansion phase. The most common grade 3/4 nonhematologic treatment-emergent adverse events were febrile neutropenia (67%), diarrhea (29%), hyponatremia (29%), and sepsis (14%). At median follow-up (28.9 months), 38% of patients were alive. Median overall survival was 10.3 months. CONCLUSIONS: Selinexor plus 7+3 is a safe regimen for patients with newly diagnosed poor-risk AML and warrants further investigation in a larger clinical trial.

Lenalidomide-based response-adapted therapy for older adults without high risk myeloma.

Combined lenalidomide and dexamethasone is a standard-of-care therapy for the treatment of older adults with multiple myeloma. Lenalidomide monotherapy has not been evaluated in newly diagnosed myeloma patients. We conducted a phase II study, evaluating a response-adapted therapy for older adults newly diagnosed with multiple myeloma without high-risk features who were ineligible for high-dose therapy and stem cell transplant. Patients were started on single-agent lenalidomide, and low-dose dexamethasone was added in the event of progressive disease, in a response-adapted approach. The primary endpoint was progression-free survival (PFS), and the International Myeloma Working Group's uniform response criteria were used to assess response and progression. Twenty-seven patients were enrolled, and 20 (74%) experienced a partial response or better to this response-adapted therapy. After a median follow-up of 69 months, the median PFS was 36 months [95% confidence interval (CI), 29·8 to not reached], and the median overall survival was 65 months (95% CI, 35·3 to not reached). Grade 3/4 adverse events were mainly haematological in nature. This response-adapted therapy in this patient population is feasible and results in durable responses that compare favourably with concurrent lenalidomide and dexamethasone. These results should be validated in prospective studies.

A phase-1/2 study of adenovirus-p53 transduced dendritic cell vaccine in combination with indoximod in metastatic solid tumors and invasive breast cancer.

BACKGROUND: Indoleamine 2, 3-dioxygenase is an enzyme that causes immunosuppression in tumors. Indoximod inhibits the indoleamine 2, 3-dioxygenase pathway and enhances immunologic responses to dendritic cell (DC) vaccines preclinically. Adenovirus p53 (Ad.p53) is used to generate DC vaccines against p53. A phase-1/2 trial of indoximod with Ad.p53-DC vaccine was conducted. MATERIALS AND METHODS: The phase-1 study combined 7 indoximod dose levels with < 6 Ad.p53-DC vaccinations every 2 weeks. Primary endpoints were maximum-tolerated dose in phase 1 and objective response in phase 2. Flow cytometry measured immune responses. RESULTS: Thirty-nine patients were treated. In combination with Ad.p53-DC vaccine, the maximum-tolerated dose of indoximod was 1600 mg twice daily. Attributable toxicities were grade 1-2. Best response was stable disease in 4 patients. Immunologic responses were detected in 7 out of 23 evaluable patients. Median progression-free survival was 13.3 weeks (95% confidence interval, 12.97-21.85) and median overall survival was 20.71 weeks (95% confidence interval, 25.75-46.15). Nine out of 22 patients (40%) benefitted from chemotherapy after vaccination. Median overall survival in chemotherapy responders was 69.4 weeks (30.1-122.1). CONCLUSIONS: Indoximod 1600 mg twice daily with Ad.p53-DC was well tolerated. There may have been a chemosensitization effect. Future trials should explore combining this treatment with chemotherapy.

Selective inhibition of matrix metalloproteinase-2 in the multiple myeloma-bone microenvironment.

Multiple myeloma is a plasma cell malignancy that homes aberrantly to bone causing extensive skeletal destruction. Despite the development of novel therapeutic agents that have significantly improved overall survival, multiple myeloma remains an incurable disease. Matrix metalloproteinase-2 (MMP-2) is associated with cancer and is significantly overexpressed in the bone marrow of myeloma patients. These data provide rationale for selectively inhibiting MMP-2 activity as a multiple myeloma treatment strategy. Given that MMP-2 is systemically expressed, we used novel "bone-seeking" bisphosphonate based MMP-2 specific inhibitors (BMMPIs) to target the skeletal tissue thereby circumventing potential off-target effects of MMP-2 inhibition outside the bone marrow-tumor microenvironment. Using in vivo models of multiple myeloma (5TGM1, U266), we examined the impact of MMP-2 inhibition on disease progression using BMMPIs. Our data demonstrate that BMMPIs can decrease multiple myeloma burden and protect against cancer-induced osteolysis. Additionally, we have shown that MMP-2 can be specifically inhibited in the multiple myeloma-bone microenvironment, underscoring the feasibility of developing targeted and tissue selective MMP inhibitors. Given the well-tolerated nature of bisphosphonates in humans, we anticipate that BMMPIs could be rapidly translated to the clinical setting for the treatment of multiple myeloma.

XPO1 inhibitor combination therapy with bortezomib or carfilzomib induces nuclear localization of IκBα and overcomes acquired proteasome inhibitor resistance in human multiple myeloma.

Acquired proteasome-inhibitor (PI) resistance is a major obstacle in the treatment of multiple myeloma (MM). We investigated whether the clinical XPO1-inhibitor selinexor, when combined with bortezomib or carfilzomib, could overcome acquired resistance in MM. PI-resistant myeloma cell lines both in vitro and in vivo and refractory myeloma patient biopsies were treated with selinexor/bortezomib or carfilzomib and assayed for apoptosis. Mechanistic studies included NFκB pathway protein expression assays, immunofluorescence microscopy, ImageStream flow-cytometry, and proximity-ligation assays. IκBα knockdown and NFκB activity were measured in selinexor/bortezomib-treated MM cells. We found that selinexor restored sensitivity of PI-resistant MM to bortezomib and carfilzomib. Selinexor/bortezomib treatment inhibited PI-resistant MM tumor growth and increased survival in mice. Myeloma cells from PI-refractory MM patients were sensitized by selinexor to bortezomib and carfilzomib without affecting non-myeloma cells. Immunofluorescence microscopy, Western blot, and ImageStream analyses of MM cells showed increases in total and nuclear IκBα by selinexor/bortezomib. Proximity ligation found increased IκBα-NFκB complexes in treated MM cells. IκBα knockdown abrogated selinexor/bortezomib-induced cytotoxicity in MM cells. Selinexor/bortezomib treatment decreased NFκB transcriptional activity. Selinexor, when used with bortezomib or carfilzomib, has the potential to overcome PI drug resistance in MM. Sensitization may be due to inactivation of the NFκB pathway by IκBα.

A Randomized Phase II Study of Linsitinib (OSI-906) Versus Topotecan in Patients With Relapsed Small-Cell Lung Cancer.

LESSONS LEARNED: Targeted therapy options for SCLC patients are limited; no agent, thus far, has resulted in a strategy promising enough to progress to phase III trials.Linsitinib, a potent insulin growth factor-1-receptor tyrosine kinase inhibitor, may be one agent with activity against SCLC.Despite lack of a reliable predictive biomarker in this disease, which may have partly contributed to the negative outcome reported here, linsitinib, although safe, showed no clinical activity in unselected, relapsed SCLC patients. BACKGROUND: Treatment of relapsed small-cell lung cancer (SCLC) remains suboptimal. Insulin growth factor-1 receptor (IGF-1R) signaling plays a role in growth, survival, and chemoresistance in SCLC. Linsitinib is a potent IGF-1R tyrosine kinase inhibitor that potentially may be active against SCLC. METHODS: In this phase II study, 8 eligible patients were randomly assigned in a 1:2 ratio to topotecan (1.5 mg/m2 intravenously or 2.3 mg/m2 orally, daily for 5 days for 4 cycles) or linsitinib (150 mg orally twice daily until progression). The primary endpoint was progression-free survival. Patients with relapsed SCLC, platinum sensitive or resistant, performance status (PS) 0-2, and adequate hematologic, renal, and hepatic function were enrolled. Patients with diabetes, cirrhosis, and those taking insulinotropic agents were excluded. Crossover to linsitinib was allowed at progression. RESULTS: Fifteen patients received topotecan (8 resistant, 3 with PS 2) and 29 received linsitinib (16 resistant, 5 with PS 2). Two partial responses were observed with topotecan. Only 4 of 15 patients with topotecan and 1 of 29 with linsitinib achieved stable disease. Median progression-free survival was 3.0 (95% confidence interval [CI], 1.5-3.6) and 1.2 (95% CI, 1.1-1.4) months for topotecan and linsitinib, respectively (p = .0001). Median survival was 5.3 (95% CI, 2.2-7.6) and 3.4 (95% CI, 1.8-5.6) months for topotecan and linsitinib, respectively (p = .71). Grade 3/4 adverse events (>5% incidence) included anemia, thrombocytopenia, neutropenia/leukopenia, diarrhea, fatigue, dehydration, and hypokalemia for topotecan; and thrombocytopenia, fatigue, and alanine aminotransferase/aspartate aminotransferase elevations for linsitinib. CONCLUSION: Linsitinib was safe but showed no clinical activity in unselected, relapsed SCLC patients.

Treatment of acquired drug resistance in multiple myeloma by combination therapy with XPO1 and topoisomerase II inhibitors.

BACKGROUND: Acquired drug resistance is the greatest obstacle to the successful treatment of multiple myeloma (MM). Despite recent advanced treatment options such as liposomal formulations, proteasome inhibitors, immunomodulatory drugs, myeloma-targeted antibodies, and histone deacetylase inhibitors, MM is still considered an incurable disease. METHODS: We investigated whether the clinical exportin 1 (XPO1) inhibitor selinexor (KPT-330), when combined with pegylated liposomal doxorubicin (PLD) or doxorubicin hydrochloride, could overcome acquired drug resistance in multidrug-resistant human MM xenograft tumors, four different multidrug-resistant MM cell lines, or ex vivo MM biopsies from relapsed/refractory patients. Mechanistic studies were performed to assess co-localization of topoisomerase II alpha (TOP2A), DNA damage, and siRNA knockdown of drug targets. RESULTS: Selinexor was found to restore sensitivity of multidrug-resistant 8226B25, 8226Dox6, 8226Dox40, and U266PSR human MM cells to doxorubicin to levels found in parental myeloma cell lines. NOD/SCID-γ mice challenged with drug-resistant or parental U266 human MM and treated with selinexor/PLD had significantly decreased tumor growth and increased survival with minimal toxicity. Selinexor/doxorubicin treatment selectively induced apoptosis in CD138/light-chain-positive MM cells without affecting non-myeloma cells in ex vivo-treated bone marrow aspirates from newly diagnosed or relapsed/refractory MM patients. Selinexor inhibited XPO1-TOP2A protein complexes (proximity ligation assay), preventing nuclear export of TOP2A in both parental and multidrug-resistant MM cell lines. Selinexor/doxorubicin treatment significantly increased DNA damage (comet assay/γ-H2AX) in both parental and drug-resistant MM cells. TOP2A knockdown reversed both the anti-tumor effect and significantly reduced DNA damage induced by selinexor/doxorubicin treatment. CONCLUSIONS: The combination of an XPO1 inhibitor and liposomal doxorubicin was highly effective against acquired drug resistance in in vitro MM models, in in vivo xenograft studies, and in ex vivo samples obtained from patients with relapsed/refractory myeloma. This drug combination synergistically induced TOP2A-mediated DNA damage and subsequent apoptosis. In addition, based on our preclinical data, we have initiated a phase I/II study with the XPO1 inhibitor selinexor and PLD (ClinicalTrials.gov NCT02186834). Initial results from both preclinical and clinical trials have shown significant promise for this drug combination for the treatment of MM.

A phase I study of indoximod in patients with advanced malignancies.

PURPOSE: Indoximod is an oral inhibitor of the indoleamine 2,3-dioxygenase pathway, which causes tumor-mediated immunosuppression. Primary endpoints were maximum tolerated dose (MTD) and toxicity for indoximod in patients with advanced solid tumors. Secondary endpoints included response rates, pharmacokinetics, and immune correlates. EXPERIMENTAL DESIGN: Our 3+3 phase I trial comprised 10 dose levels (200, 300, 400, 600, and 800 mg once/day; 600, 800, 1200, 1600, and 2000 mg twice/day). Inclusion criteria were measurable metastatic solid malignancy, age ≥18 years, and adequate organ/marrow function. Exclusion criteria were chemotherapy ≤ 3 weeks prior, untreated brain metastases, autoimmune disease, or malabsorption. RESULTS: In 48 patients, MTD was not reached at 2000 mg twice/day. At 200 mg once/day, 3 patients previously treated with checkpoint inhibitors developed hypophysitis. Five patients showed stable disease >6 months. Indoximod plasma AUC and Cmax plateaued above 1200mg. Cmax (~12 µM at 2000 mg twice/day) occurred at 2.9 hours, and half-life was 10.5 hours. C reactive protein (CRP) levels increased across multiple dose levels. CONCLUSIONS: Indoximod was safe at doses up to 2000 mg orally twice/day. Best response was stable disease >6 months in 5 patients. Induction of hypophysitis, increased tumor antigen autoantibodies and CRP levels were observed.

Randomized multicenter phase 2 study of pomalidomide, cyclophosphamide, and dexamethasone in relapsed refractory myeloma.

Pomalidomide and low-dose dexamethasone (PomDex) is standard treatment of lenalidomide refractory myeloma patients who have received >2 prior therapies. We aimed to assess the safety and efficacy of the addition of oral weekly cyclophosphamide to standard PomDex. We first performed a dose escalation phase 1 study to determine the recommended phase 2 dose of cyclophosphamide in combination with PomDex (arm A). A randomized, multicenter phase 2 study followed, enrolling patients with lenalidomide refractory myeloma. Patients were randomized (1:1) to receive pomalidomide 4 mg on days 1 to 21 of a 28-day cycle in combination with weekly dexamethasone (arm B) or pomalidomide, dexamethasone, and cyclophosphamide (PomCyDex) 400 mg orally on days 1, 8, and 15 (arm C). The primary end point was overall response rate (ORR). Eighty patients were enrolled (10 in phase 1 and 70 randomized in phase 2: 36 to arm B and 34 to arm C). The ORR was 38.9% (95% confidence interval [CI], 23-54.8%) and 64.7% (95% CI, 48.6-80.8%) for arms B and C, respectively (P = .035). As of June 2015, 62 of the 70 randomized patients had progressed. The median progression-free survival (PFS) was 4.4 (95% CI, 2.3-5.7) and 9.5 months (95% CI, 4.6-14) for arms B and C, respectively (P = .106). Toxicity was predominantly hematologic in nature but was not statistically higher in arm C. The combination of PomCyDex results in a superior ORR and PFS compared with PomDex in patients with lenalidomide refractory multiple myeloma. The trial was registered at www.clinicaltrials.gov as #NCT01432600.

Anti-myeloma effect of pharmacological inhibition of Notch/gamma-secretase with RO4929097 is mediated by modulation of tumor microenvironment.

Multiple myeloma (MM), a blood cancer characterized by the uncontrolled proliferation of plasma cells, remains incurable by current therapy. Notch signaling has been implicated in the growth and chemoresistance of various cancer types including MM, and therefore we hypothesized that targeting the Notch pathway could be beneficial for the treatment of this disease. Here, we report an anti-tumor effect of Notch/γ-secretase inhibitor RO4929097 in a pre-clinical model of MM. We demonstrate that this effect was associated with decreased angiogenesis and significant down-regulation of TGF-ß1. In addition, we also show that treatment with RO4929097 results in decreased number and functional activity of osteoclasts. Taken together, our data indicate that targeting Notch may be considered as a new strategy to be tested for MM therapy.

Pediatric phase I trial of oral sorafenib and topotecan in refractory or recurrent pediatric solid malignancies.

Targeted kinase inhibitors and camptothecins have shown preclinical and clinical activity in several cancers. This trial evaluated the maximum tolerated dose (MTD) and dose-limiting toxicities of sorafenib and topotecan administered orally in pediatric patients with relapsed solid tumors. Sorafenib was administered twice daily and topotecan once daily on days 1-5 and 8-12 of each 28-day course. The study utilized a standard 3 + 3 dose escalation design. Three dose levels (DL) were evaluated: (1) sorafenib 150 mg/m(2) and topotecan 1 mg/m(2) ; (2) sorafenib 150 mg/m(2) and topotecan 1.4 mg/m(2) ; and (3) sorafenib 200 mg/m(2) and topotecan 1.4 mg/m(2) . Pharmacokinetics were ascertained and treatment response assessed. Thirteen patients were enrolled. DL2 was the determined MTD. Grade 4 thrombocytopenia delaying therapy for >7 days was observed in one of six patients on DL2, and grade 4 neutropenia that delayed therapy in two of three patients on DL3. A patient with preexisting cardiac failure controlled with medication developed a transient drop in the left ventricular ejection fraction that improved when sorafenib was withheld. Sorafenib exposure with or without topotecan was comparable, and the concentration-time profiles for topotecan alone and in combination with sorafenib were similar. One objective response was noted in a patient with fibromatosis. We determined MTD to be sorafenib 150 mg/m(2) twice daily orally on days 1-28 combined with topotecan 1.4 mg/m(2) once daily on days 1-5 and 8-12. While these doses are 1 DL below the MTD of the agents individually, pharmacokinetic studies suggested adequate drug exposure without drug interactions. The combination had limited activity in the population studied.

Identification of Synergistic, Clinically Achievable, Combination Therapies for Osteosarcoma.

Systemic therapy has improved osteosarcoma event-free and overall survival, but 30-50% of patients originally diagnosed will have progressive or recurrent disease, which is difficult to cure. Osteosarcoma has a complex karyotype, with loss of p53 in the vast majority of cases and an absence of recurrent, targetable pathways. In this study, we explored 54 agents that are clinically approved for other oncologic indications, agents in active clinical development, and others with promising preclinical data in osteosarcoma at clinically achievable concentrations in 5 osteosarcoma cell lines. We found significant single-agent activity of multiple agents and tested 10 drugs in all permutations of two-drug combinations to define synergistic combinations by Chou and Talalay analysis. We then evaluated order of addition to choose the combinations that may be best to translate to the clinic. We conclude that the repurposing of chemotherapeutics in osteosarcoma by using an in vitro system may define novel drug combinations with significant in vivo activity. In particular, combinations of proteasome inhibitors with histone deacetylase inhibitors and ixabepilone and MK1775 demonstrated excellent activity in our assays.

Impact of the 2010 Consensus Recommendations of the Clinical Trial Design Task Force of the NCI Investigational Drug Steering Committee.

Oncology phase III trials have a high failure rate, leading to high development costs. The Clinical Trials Design Task Force of the Investigational Drug Steering Committee of the NCI Cancer Therapy and Evaluation Program developed Recommendations regarding the design of phase II trials. We report here on the results of a Concordance Group review charged with documenting whether concordance rates improved after the publication of the Recommendations. One hundred and fifty-five trials were reviewed. Letter of Intents (LOI) from the post-Recommendation period were more likely to be randomized (44% vs. 34%) and biomarker selected (19% vs. 10%). Single-arm studies using time-to-event endpoints (benchmarked against historical data) were similar, as was the type of tumor. There was a significant improvement in the rate of concordance, with 74% of LOIs scored as concordant compared with 58% before the Recommendations (P = 0.042). This included a marked decrease in the use of single-arm designs to evaluate the activity of drug combinations (19% vs. 5%, P = 0.009). There were areas for which clarification was warranted, including the need for protocols to include further development plans, the use of realistic benchmarks, the careful evaluation of historical controls, and the use of a standard treatment option as a control. Ongoing critical evaluation of current trial design methodology and the development of new Guidelines when appropriate will continue to improve drug development ensuring that safe and effective cancer therapeutics are made available to our patients as quickly and efficiently as possible.

Effect of Age on Clinical Outcomes in Phase 1 Trial Participants.

BACKGROUND: Most persons with cancer living in the United States are older than 65 years of age; however, in general, elderly persons are under-represented in clinical trials and outcomes data are lacking. METHODS: Outcomes data were analyzed of elderly participants (≥65 years of age) enrolled in phase 1 clinical trials and the results compared with those of younger patients. All consecutive, single-center, phase 1 oncology trials initiated and completed at the H. Lee Moffitt Cancer Center & Research Institute between 1997 and 2007 were included. Patient data (including survival, response, and toxicity rates) were extracted from a cancer registry database and electronic medical records at Moffitt Cancer Center. RESULTS: After excluding multi-institution trials, we analyzed 39 trials for a total of 1,162 enrolled study participants, 32.7% of whom were elderly. Among patients who underwent transplantation, median survival rates were worse in those who were elderly compared with those who were younger (44.9 vs 32.9 months; P = .0037). However, in the no-transplantation setting, participants who were elderly had a median survival rate of 10.9 months (95% confidence interval [CI]: 8.9-13.1) compared with 8.8 months (95% CI: 7.9-10.3) in those who were younger (P = .15). Both groups had similar overall response rates (15.2% vs 13.1%) and similar treatment-related mortality rates (1% vs 0.9%, respectively). Adverse events occurring among the elderly and younger participants were not statistically significant. CONCLUSIONS: Survival, response, toxicity, and treatment-related mortality rates were not significantly different between the elderly and younger phase 1 trial participants in the no-transplantation setting. Regardless of the complex pharmacological profiles and logistical issues involved in treating the elderly population, our data imply that elderly study participants do at least as well as their younger counterparts, contributing to the justification of increasing the phase 1 trial enrollment of elderly patients.

Selective Nuclear Export Inhibitor KPT-330 Enhances the Antitumor Activity of Gemcitabine in Human Pancreatic Cancer.

Pancreatic cancer is an aggressive and deadly malignancy responsible for the death of over 37,000 Americans each year. Gemcitabine-based therapy is the standard treatment for pancreatic cancer but has limited efficacy due to chemoresistance. In this study, we evaluated the in vitro and in vivo effects of gemcitabine combined with the selective nuclear export (CRM1) inhibitor KPT-330 on pancreatic cancer growth. Human pancreatic cancer MiaPaCa-2 and metastatic pancreatic cancer L3.6pl cell lines were treated with different concentrations of KPT-330 and gemcitabine alone or in combination, and anchorage-dependent/independent growth was recorded. In addition, L3.6pl cells with luciferase were injected orthotopically into the pancreas of athymic nude mice, which were treated with (i) vehicle (PBS 1 mL/kg i.p., 2/week and povidone/pluronic F68 1 mL/kg p.o., 3/week), (ii) KPT-330 (20 mg/kg p.o., 3/week), (iii) gemcitabine (100 mg/kg i.p., 2/week), or (iv) KPT-330 (10 mg/kg) + gemcitabine (50 mg/kg) for 4 weeks. KPT-330 and gemcitabine alone dose-dependently inhibited anchorage-dependent growth in vitro and tumor volume in vivo compared with vehicle treatment. However, the combination inhibited growth synergistically. In combination, KPT-330 and gemcitabine acted synergistically to enhance pancreatic cancer cell death greater than each single-agent therapy. Mechanistically, KPT-330 and gemcitabine promoted apoptosis, induced p27, depleted survivin, and inhibited accumulation of DNA repair proteins. Together, our data suggest that KPT-330 potentiates the antitumor activity of gemcitabine in human pancreatic cancer through inhibition of tumor growth, depletion of the antiapoptotic proteins, and induction of apoptosis.

Randomized Trial of Oral Cyclophosphamide and Veliparib in High-Grade Serous Ovarian, Primary Peritoneal, or Fallopian Tube Cancers, or BRCA-Mutant Ovarian Cancer.

PURPOSE: Veliparib, a PARP inhibitor, demonstrated clinical activity in combination with oral cyclophosphamide in patients with BRCA-mutant solid tumors in a phase I trial. To define the relative contribution of PARP inhibition to the observed clinical activity, we conducted a randomized phase II trial to determine the response rate of veliparib in combination with cyclophosphamide compared with cyclophosphamide alone in patients with pretreated BRCA-mutant ovarian cancer or in patients with pretreated primary peritoneal, fallopian tube, or high-grade serous ovarian cancers (HGSOC). EXPERIMENTAL DESIGN: Adult patients were randomized to receive cyclophosphamide alone (50 mg orally once daily) or with veliparib (60 mg orally once daily) in 21-day cycles. Crossover to the combination was allowed at disease progression. RESULTS: Seventy-five patients were enrolled and 72 were evaluable for response; 38 received cyclophosphamide alone and 37 the combination as their initial treatment regimen. Treatment was well tolerated. One complete response was observed in each arm, with three partial responses (PR) in the combination arm and six PRs in the cyclophosphamide alone arm. Genetic sequence and expression analyses were performed for 211 genes involved in DNA repair; none of the detected genetic alterations were significantly associated with treatment benefit. CONCLUSION: This is the first trial that evaluated single-agent, low-dose cyclophosphamide in HGSOC, peritoneal, fallopian tube, and BRCA-mutant ovarian cancers. It was well tolerated and clinical activity was observed; the addition of veliparib at 60 mg daily did not improve either the response rate or the median progression-free survival.

Canonical Wnt pathway inhibitor ICG-001 induces cytotoxicity of multiple myeloma cells in Wnt-independent manner.

Canonical Wnt signaling has been implicated in the regulation of multiple myeloma (MM) growth. Here, we investigated whether the targeting of this pathway with a novel pharmacological inhibitor ICG-001 would result in an anti-tumor effect and improvement of chemosensitivity in MM. As expected, ICG-001 specifically down-regulated ß-catenin/TCF-mediated transcription in MM cells. Treatment with ICG-001 resulted in growth arrest and apoptosis in MM cell lines and primary MM cells. Moreover, ICG-001 enhanced the cytotoxic effects of doxorubicin and melphalan and abrogated chemoresistance of MM cells to these chemotherapeutics induced by bone marrow stroma. The cytotoxic effect of ICG-001 was caspase-dependent and mediated through transcriptional up-regulation of BH3-only pro-apoptotic members of the Bcl-2 family Noxa and Puma but not through inhibition of canonical Wnt signaling. ICG-001 selectively induced apoptosis in primary MM cells but did not affect non-MM cells of the bone marrow microenvironment. Experiments using a xenograft model of MM showed substantial anti-tumor effects of this compound in vivo. Thus, our study demonstrated that the small molecule inhibitor ICG-001 has strong anti-MM effects and could be developed further for therapeutic intervention in this disease.

A first in man phase I trial of the oral immunomodulator, indoximod, combined with docetaxel in patients with metastatic solid tumors.

BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) is an enzyme that tumors use to create a state of immunosuppression. Indoximod is an IDO pathway inhibitor. Preclinical studies demonstrated that indoximod combined with chemotherapy was synergistic in a mouse model of breast cancer. A phase I 3+3 trial was designed to study the combination of docetaxel and indoximod. METHODS: Docetaxel was administered at 60 mg/m2 intravenously every 3 weeks dose levels 1-4 and 75 mg/m2 for dose level 5. Indoximod was given at 300, 600, 1000, 2000, and 1200 mg PO twice daily continuously for levels 1-5, respectively. Serum drug levels were measured. RESULTS: Twenty-seven patients were treated, with 22 evaluable for response. DLTs included grade 3 dehydration (level 1), hypotension(level 4), mucositis (level 4) and grade 5 enterocolitis (level 2). Dose level 5 is the recommended phase II dose. The most frequent adverse events were fatigue (58.6%), anemia (51.7%), hyperglycemia (48.3%), infection (44.8%), and nausea (41.4%). There were 4 partial responses (2 breast, 1 NSCLC, 1 thymic tumor). No drug-drug interactions were noted. CONCLUSIONS: Docetaxel plus indoximod was well tolerated with no increase in expected toxicities or pharmacokinetic interactions. It was active in a pretreated population of patients with metastatic solid tumors.

Interrogating two schedules of the AKT inhibitor MK-2206 in patients with advanced solid tumors incorporating novel pharmacodynamic and functional imaging biomarkers.

PURPOSE: Multiple cancers harbor genetic aberrations that impact AKT signaling. MK-2206 is a potent pan-AKT inhibitor with a maximum tolerated dose (MTD) previously established at 60 mg on alternate days (QOD). Due to a long half-life (60-80 hours), a weekly (QW) MK-2206 schedule was pursued to compare intermittent QW and continuous QOD dosing. EXPERIMENTAL DESIGN: Patients with advanced cancers were enrolled in a QW dose-escalation phase I study to investigate the safety and pharmacokinetic-pharmacodynamic profiles of tumor and platelet-rich plasma (PRP). The QOD MTD of MK-2206 was also assessed in patients with ovarian and castration-resistant prostate cancers and patients with advanced cancers undergoing multiparametric functional magnetic resonance imaging (MRI) studies, including dynamic contrast-enhanced MRI, diffusion-weighted imaging, magnetic resonance spectroscopy, and intrinsic susceptibility-weighted MRI. RESULTS: A total of 71 patients were enrolled; 38 patients had 60 mg MK-2206 QOD, whereas 33 received MK-2206 at 90, 135, 150, 200, 250, and 300 mg QW. The QW MK-2206 MTD was established at 200 mg following dose-limiting rash at 250 and 300 mg. QW dosing appeared to be similarly tolerated to QOD, with toxicities including rash, gastrointestinal symptoms, fatigue, and hyperglycemia. Significant AKT pathway blockade was observed with both continuous QOD and intermittent QW dosing of MK-2206 in serially obtained tumor and PRP specimens. The functional imaging studies demonstrated that complex multiparametric MRI protocols may be effectively implemented in a phase I trial. CONCLUSIONS: Treatment with MK-2206 safely results in significant AKT pathway blockade in QOD and QW schedules. The intermittent dose of 200 mg QW is currently used in phase II MK-2206 monotherapy and combination studies (NCT00670488).