Continuous 72-h infusion of zosuquidar with chemotherapy in patients with newly diagnosed acute myeloid leukemia stratified for leukemic blast P-glycoprotein phenotype.

PURPOSE: To evaluate the safety, tolerability, pharmacodynamics (PD), and potential efficacy of zosuquidar (Zos) in combination with daunorubicin and cytarabine in elderly patients with newly diagnosed acute myeloid leukemia (AML). METHODS: Patients with AML (N = 106) were treated with Zos as a 72-h continuous intravenous (CIV) infusion along with chemotherapy. Leukemic blasts from the patients were assessed for P-glycoprotein (P-gp) function using ex vivo bioassays for screening and PD analyses. Patient outcomes were categorized according to primary (N = 56) and secondary (N = 50) AML cohorts (pAML and sAML, respectively) and stratified into P-gp-high and P-gp-low subgroups. RESULTS: Patients with P-gp-high blasts exhibited comparable overall remission rates (ORR) to those with P-gp-low blasts in both the pAML and sAML cohorts. The P-gp-high and P-gp-low subgroups in the pAML cohort exhibited similar overall survival (OS). Patients with sAML and P-gp-high blasts exhibited significantly better OS than those in the P-gp-low subgroup. PD analyses revealed that Zos infusion provided 82 h of uninterrupted effective ≥ 90% inhibition of P-gp functional activity in leukemic blasts. CONCLUSIONS: These observations provide evidence of Zos efficacy with the 72-h CIV infusion approach. The similarity of ORR in the P-gp-high and P-gp-low subgroups is consistent with Zos-mediated neutralization of P-gp as verified by PD analyses. The bioassay identified sAML patients most likely to respond favorably to Zos co-therapy indicating feasibility as a Zos companion diagnostic. A follow-up placebo-controlled trial is needed to verify these promising results. GOV IDENTIFIER: NCT00129168; First posted on August 11, 2005.

Carboplatin-induced upregulation of pan ß-tubulin and class III ß-tubulin is implicated in acquired resistance and cross-resistance of ovarian cancer.

Resistance to platinum- and taxane-based chemotherapy represents a major obstacle to long-term survival in ovarian cancer (OC) patients. Here, we studied the interplay between acquired carboplatin (CBP) resistance using two OC cell models, MES-OV CBP and SK-OV-3 CBP, and non-P-glycoprotein-mediated cross-resistance to paclitaxel (TAX) observed only in MES-OV CBP cells. Decreased platination, mesenchymal-like phenotype, and increased expression of α- and γ-tubulin were observed in both drug-resistant variants compared with parental cells. Both variants revealed increased protein expression of class III ß-tubulin (TUBB3) but differences in TUBB3 branching and nuclear morphology. Transient silencing of TUBB3 sensitized MES-OV CBP cells to TAX, and surprisingly also to CBP. This phenomenon was not observed in the SK-OV-3 CBP variant, probably due to the compensation by other ß-tubulin isotypes. Reduced TUBB3 levels in MES-OV CBP cells affected DNA repair protein trafficking and increased whole-cell platination level. Furthermore, TUBB3 depletion augmented therapeutic efficiency in additional OC cells, showing vice versa drug-resistant pattern, lacking ß-tubulin isotype compensation visible at the level of total ß-tubulin (TUBB) in vitro and ex vivo. In summary, the level of TUBB in OC should be considered together with TUBB3 in therapy response prediction.

A clinical trial of zosuquidar plus gemtuzumab ozogamicin (GO) in relapsed or refractory acute myeloid leukemia (RR AML): evidence of efficacy based on leukemic blast P-glycoprotein functional phenotype.

PURPOSE: To evaluate safety, tolerability, potential efficacy, and pharmacodynamics (PD) of zosuquidar (Zos) in combination with gemtuzumab ozogamicin (GO) in elderly patients with relapsed or refractory (RR) acute myeloid leukemia (AML). METHODS: Patients with RR AML (N = 41) were treated with Zos as a 48-h continuous intravenous infusion initiated 4 h prior to a 2-h infusion of GO on days 1 and 15. P-glycoprotein (P-gp) status of the patients' leukemic blasts and PD determinations were assessed with ex vivo bioassays. Patient outcomes were analyzed for the total cohort and as stratified into P-gp-positive (P-gp +) and P-gp-negative (P-gp‒) subgroups. RESULTS: The eligible cohort exhibited a 34% overall remission rate (ORR), a composite of patients that exhibited complete remission (CR), CR with incomplete platelet recovery, or morphologic remission. Patients with 1st relapsed disease exhibited 40% ORR. P-gp phenotype did not significantly predict ORR. However, the P-gp + subgroup exhibited a greater median overall survival (OS) of 6.0 months vs. 1.8 months for patients in the P-gp‒ subgroup (p = 0.01). PD analyses revealed 90-95% inhibition of blast P-gp function during Zos infusion. Treatment related toxicities were observed and resolved with decrease or discontinued Zos or GO dosages. CONCLUSIONS: Zos plus GO elicited appreciable ORR for an elderly patient population with RR AML. The greater OS of the P-gp + subgroup vs. the P-gp‒ subgroup suggests that patients with P-gp + leukemic blasts were being more effectively targeted by GO with Zos co-therapy. The poorer OS of the P-gp‒ subgroup suggests activity of Zos-insensitive multidrug resistant mechanisms. GOV IDENTIFIER: NCT00233909; First posted October 06, 2005.

A Phase I Trial of the ABCB1 Inhibitor, Oral Valspodar, in Combination With Paclitaxel in Patients With Advanced Solid Tumors.

OBJECTIVES: Multidrug resistance mediated by P-glycoprotein is a potential obstacle to cancer treatment. This phase 1 trial determined the safety of paclitaxel with valspodar, a P-glycoprotein inhibitor, in patients with advanced solid tumors. METHODS: Patients were treated with single-agent paclitaxel Q3W 175 mg/m 2 (or 135 mg/m 2 if heavily pretreated) as a 3-hour infusion. If their disease was stable (SD) or progressive (PD), paclitaxel at 30% (52.5 mg/m 2 ), 40% (70 mg/m 2 ), or 50% (87.5 mg/m 2 ) of 175 mg/m 2 (full dose) was administered with valspodar 5 mg/kg orally 4 times daily for 12 doses. Pharmacokinetic sampling (PK) for paclitaxel and valspodar was performed during single-agent and combination therapy. RESULTS: Sixteen patients had SD/PD after one cycle of paclitaxel and then received paclitaxel at 30% (n=3), 40% (n=3), and 50% (n=10) with valspodar. Hematologic adverse events (AEs) including myelosuppression at paclitaxel 40% were comparable to those of full-dose paclitaxel. Non-hematologic AEs consisted of reversible hepatic (hyperbilirubinemia and transaminitis) and neurologic AEs (ataxia and paresthesias). Eleven patients experienced SD with a median of 12.7 weeks (range, 5.4 to 36.0), 4 patients progressed, and 1 was inevaluable. Reduced dose paclitaxel with valspodar resulted in lower plasma peak concentrations of paclitaxel; otherwise, concentrations were similar to single-agent paclitaxel. CONCLUSION: Paclitaxel at 70 mg/m 2 was administered safely with valspodar. Limited efficacy in hematologic and solid tumors resulted in discontinuation of its clinical development and other transporter inhibitors. Recently, the development of ATP-binding cassette transporter inhibitors has been reconsidered to mitigate resistance to antibody-drug conjugates.

Safety, tolerability and efficacy of agonist anti-CD27 antibody (varlilumab) administered in combination with anti-PD-1 (nivolumab) in advanced solid tumors.

BACKGROUND: Phase 1/2 dose-escalation and expansion study evaluating varlilumab, a fully human agonist anti-CD27 mAb, with nivolumab in anti-PD-1/L1 naïve, refractory solid tumors. METHODS: Phase 1 evaluated the safety of varlilumab (0.1-10 mg/kg) with nivolumab (3 mg/kg) administered once every 2 weeks. Phase 2 evaluated varlilumab regimens (3 mg/kg once every 2 weeks, 3 mg/kg once every 12 weeks, and 0.3 mg/kg once every 4 weeks) with nivolumab 240 mg once every 2 weeks in tumor-specific cohorts. Primary objective was safety; key clinical endpoints included objective response rate (ORR) and overall survival rate at 12 months (OS12) (glioblastoma (GBM) only). Exploratory objectives included determination of effects on peripheral blood and intratumoral immune signatures. RESULTS: 175 patients were enrolled (36 in phase 1 and 139 in phase 2). Phase 1 dose-escalation proceeded to the highest varlilumab dose level without determining a maximum tolerated dose. In phase 2, ORR were ovarian 12.5%, squamous cell carcinoma of the head and neck 12.5%, colorectal cancer 5%, and renal cell carcinoma 0%; GBM OS12 was 40.9%. Increased tumor PD-L1 and intratumoral T cell infiltration were observed in ovarian cancer patients, with increases of ≥5% associated with better progression-free survival. The most common treatment related adverse events were fatigue (18%), pruritus (16%), and rash (15%). CONCLUSION: Varlilumab and nivolumab were well tolerated, without significant toxicity beyond that expected for each agent alone. Clinical activity was observed in patients that are typically refractory to anti-PD-1 therapy, however, overall was not greater than expected for nivolumab monotherapy. Treatment was associated with proinflammatory changes in the tumor microenvironment, particularly in ovarian cancer where the changes were associated with better clinical outcomes. TRIAL REGISTRATION NUMBER: NCT02335918.

Safety and activity of varlilumab, a novel and first-in-class agonist anti-CD27 antibody, for hematologic malignancies.

CD27, a costimulatory molecule on T cells, induces intracellular signals mediating cellular activation, proliferation, effector function, and cell survival on binding to its ligand, CD70. Varlilumab, a novel, first-in-class, agonist immunoglobulin G1 anti-CD27 antibody, mediates antitumor immunity and direct killing of CD27+ tumor cells in animal models. This first-in-human, dose-escalation, and expansion study evaluated varlilumab in patients with hematologic malignancies. Primary objectives were to assess safety and the maximum tolerated and optimal biologic doses of varlilumab. Secondary objectives were to evaluate pharmacokinetics, pharmacodynamics, immunogenicity, and antitumor activity. In a 3 + 3 dose-escalation design, 30 patients with B-cell (n = 25) or T-cell (n = 5) malignancies received varlilumab (0.1, 0.3, 1, 3, or 10 mg/kg IV) as a single dose with a 28-day observation period, followed by weekly dosing (4 doses per cycle, up to 5 cycles, depending on tumor response). In an expansion cohort, 4 additional patients with Hodgkin lymphoma received varlilumab at 0.3 mg/kg every 3 weeks (4 doses per cycle, up to 5 cycles). No dose-limiting toxicities were observed. Treatment-related adverse events, generally grade 1 to 2, included fatigue, decreased appetite, anemia, diarrhea, and headache. Exposure was linear and dose-proportional across dose groups and resulted in increases in proinflammatory cytokines and soluble CD27. One patient with stage IV Hodgkin lymphoma experienced a complete response and remained in remission at >33 months with no further anticancer therapy. These data support further investigation of varlilumab for hematologic malignancies, particularly in combination approaches targeting nonredundant immune regulating pathways. This trial was registered at www.clinicaltrials.gov as #NCT01460134.

Genomic stability at the coding regions of the multidrug transporter gene ABCB1: insights into the development of alternative drug resistance mechanisms in human leukemia cells.

AIM: Despite considerable efforts to reverse clinical multidrug resistance (MDR), targeting the predominant multidrug transporter ABCB1/P-glycoprotein (P-gp) using small molecule inhibitors has been unsuccessful, possibly due to the emergence of alternative drug resistance mechanisms. However, the non-specific P-gp inhibitor cyclosporine (CsA) showed significant clinical benefits in patients with acute myeloid leukemia (AML), which likely represents the only proof-of-principle clinical trial using several generations of MDR inhibitors. Nevertheless, the mutational mechanisms that may underlie unsuccessful MDR modulation by CsA are not elucidated because of the absence of CsA-relevant cellular models. In this study, our aims were to establish CsA-resistant leukemia models and to examine the presence or absence of ABCB1 exonic mutations in these models as well as in diverse types of human cancer samples including AMLs. METHODS: Drug-resistant lines were established by stepwise drug co-selection and characterized by drug sensitivity assay, rhodamine-123 accumulation, [3H]-labeled drug export, ABCB1 cDNA sequencing, and RNase protection assay. The genomic stability of the ABCB1 coding regions was evaluated by exome sequencing analysis of variant allele frequencies in human populations. Moreover, the mutational spectrum of ABCB1 was further assessed in diverse types of cancer samples including AMLs in the Cancer Genome Atlas (TCGA) at the National Cancer Institute. RESULTS: We report the development of two erythroleukemia variants, RVC and RDC, which were derived by stepwise co-selection of K562/R7 drug-resistant leukemia cells with the etoposide-CsA and doxorubicin-CsA drug combinations, respectively. Interestingly, both RVC and RDC cell lines, which retained P-gp expression, showed altered multidrug-resistant phenotypes that were resistant to CsA modulation. Strikingly, no mutations were found in the ABCB1 coding regions in these variant cells even under long-term stringent drug selection. Genomically, ABCB1 displayed relatively low variant allele frequencies in human populations when compared with several ABC superfamily members. Moreover, ABCB1 also exhibited a very low mutational frequency in AMLs compared with all types of human cancer. In addition, we found that CsA played a role in undermining the selection of highly drug-resistant cells via induction of low-level and unstable drug resistance. CONCLUSION: Our data indicate that ABCB1 coding regions are genomically stable and relatively resistant to drug-induced mutations. Non-ABCB1 mutational mechanisms are responsible for the drug-resistant phenotypes in both RVC and RDC cell lines, which are also prevalent in clinical AML patients. Accordingly, we propose several relevant models that account for the development of alternative drug resistance mechanisms in the absence of ABCB1 mutations.

First-in-Human, First-in-Class Phase I Trial of the Anti-CD47 Antibody Hu5F9-G4 in Patients With Advanced Cancers.

PURPOSE: To evaluate the safety, pharmacokinetics, and pharmacodynamics of Hu5F9-G4 (5F9), a humanized IgG4 antibody that targets CD47 to enable phagocytosis. PATIENTS AND METHODS: Adult patients with solid tumors were treated in four cohorts: part A, to determine a priming dose; part B, to determine a weekly maintenance dose; part C, to study a loading dose in week 2; and a tumor biopsy cohort. RESULTS: Sixty-two patients were treated: 11 in part A, 14 in B, 22 in C, and 15 in the biopsy cohort. Part A used doses that ranged from 0.1 to 3 mg/kg. On the basis of tolerability and receptor occupancy studies that showed 100% CD47 saturation on RBCs, 1 mg/kg was selected as the priming dose. In subsequent groups, patients were treated with maintenance doses that ranged from 3 to 45 mg/kg, and most toxicities were mild to moderate. These included transient anemia (57% of patients), hemagglutination on peripheral blood smear (36%), fatigue (64%), headaches (50%), fever (45%), chills (45%), hyperbilirubinemia (34%), lymphopenia (34%), infusion-related reactions (34%), and arthralgias (18%). No maximum tolerated dose was reached with maintenance doses up to 45 mg/kg. At doses of 10 mg/kg or more, the CD47 antigen sink was saturated by 5F9, and a 5F9 half-life of approximately 13 days was observed. Strong antibody staining of tumor tissue was observed in a patient at 30 mg/kg. Two patients with ovarian/fallopian tube cancers had partial remissions for 5.2 and 9.2 months. CONCLUSION: 5F9 is well tolerated using a priming dose at 1 mg/kg on day 1 followed by maintenance doses of up to 45 mg/kg weekly.

The Syk inhibitor R406 is a modulator of P-glycoprotein (ABCB1)-mediated multidrug resistance.

In a previously published study, higher levels of spleen tyrosine kinase (Syk) were observed in recurrent post-chemotherapy ovarian cancers compared to primary tumors. Syk inhibition was found to stabilize microtubules and potentiate paclitaxel activity in cellular models of taxane-resistant ovarian cancers. We further studied the effects of Syk inhibition on paclitaxel activity in Syk(+) ovarian cancer cell models and in variants selected for taxane resistance. Syk inhibition was accomplished using RNAi and by exposure to the small molecule competitive inhibitor R406, the active metabolite of fostamatinib. Exposure to R406 or to a SYK-specific pool of siRNAs did not alter taxane activity in the OVCAR-3 cell line, which has the most Syk content in our panel of nine human ovarian cancer cell lines. However, treatment with R406 sensitised the multidrug resistant (MDR) variants MES-SA/Dx5 and SK-OV-3/TR to paclitaxel in a dose-dependent manner resulting from the inhibition of the ABCB1/P-glycoprotein (P-gp) drug transporter. These observations are Syk-independent since both MDR cell models are Syk negative. R406 modulated resistance to other known P-gp substrates, and we observed orthovanadate-sensitive ATPase stimulation resulting from treatment with R406. These data indicate that the chemo-sensitizing effect of R406 in taxane-resistant cells previously reported was not associated with Syk but resulted from the modulation of P-gp-mediated MDR.

Evidence of a role for functional heterogeneity in multidrug resistance transporters in clinical trials of P-glycoprotein modulation in acute myeloid leukemia.

BACKGROUND: Multidrug resistance (MDR) transporter proteins such as P-glycoprotein (P-gp) efflux a variety of chemotherapeutic drugs from acute myeloid leukemia (AML) blasts leading to clinical drug resistance. METHODS: This study examined heterogeneity of MDR functional efflux by AML blasts using two flow cytometry bioassays. Bone marrow specimens (N = 50) from elderly patients with newly diagnosed AML were analyzed for CD34+ blasts with MDR efflux function. Efflux was measured with a fluorescent dye (DiOC2 ) as a surrogate for oncology drugs that are substrates for MDR efflux. P-gp-mediated efflux was differentiated from non-P-gp MDR activities using zosuquidar, a highly selective P-gp modulator. The bioassays included a zosuquidar-dependent DiOC2 accumulation bioassay that measured only P-gp. The second method, termed the efflux bioassay, could detect P-gp and other non-P-gp efflux depending on bioassay culture conditions. RESULTS: Sixty-two percent of the specimens were considered positive for blasts with P-gp function, and 26% of such P-gp-positive specimens also exhibited zosuquidar-resistant (i.e., non-P-gp) MDR efflux activity; 37% of P-gp-negative AML blast specimens displayed zosuquidar-resistant MDR function in the efflux bioassay. CONCLUSIONS: These results confirm the heterogeneous nature of MDR efflux pumps in AML blasts, and provide support for the hypothesis that non-P-gp MDR contributed to negative results with zosuquidar in AML trials like ECOG-ACRIN E3999. © 2018 International Clinical Cytometry Society.

Expenditures on Oncology Drugs and Cancer Mortality-to-Incidence Ratio in Central and Eastern Europe.

BACKGROUND: There is a steady decline in cancer mortality in Western Europe (WE), but this trend is not so obvious in Central and Eastern Europe (CEE). One of the largest discrepancies between WE and CEE is the level of investment in cancer care. The objective of our analysis was to examine the correlation between mortality-to-incidence (M/I) ratio and expenditures on oncology drugs in CEE and WE. MATERIALS AND METHODS: This cross-sectional analysis was done on publicly available data. Data on expenditures for oncology drugs were obtained from QuintilesIMS, and data on M/I ratio from Globocan. The main outcome was mortality-to-incidence ratio, and the primary analysis was performed by Spearman's rank correlation. RESULTS: There is a large discrepancy in expenditure on oncology drugs per cancer case between WE and CEE, and within CEE. Average expenditure on oncology drugs per capita as well as per new cancer case was 2.5 times higher in WE than in CEE. Availability of oncology drugs was highest in Germany (100%), relatively similar in WE (average of 91%), but in CEE it ranged from 37% to 86%, with an average of 70%. Annual expenditures on all oncology drugs per new cancer case was significantly negatively correlated with the M/I ratio (Spearman's ρ = -0.90, p < .001). CONCLUSION: There is a financial threshold for oncology drugs per cancer case needed to increase survival. Based on significantly lower expenditures for oncology drugs in CEE in comparison with WE, more investment for drugs as well as better, more organized, value- oriented consumption is needed. IMPLICATIONS FOR PRACTICE: Cancer is not treated equally successfully in Western Europe (WE) and in Central and Eastern Europe (CEE). This study showed that success in treatment of cancer is associated with the amount of money invested in oncology drugs. CEE countries spend on average 2.5 times less than WE countries for oncology drugs per new cancer case. These findings should be used by health care providers and oncologists struggling for more resources and better, more organized, evidence-based allocation of these resources as well as better oncology outcomes.

A safety, tolerability, and pharmacokinetic analysis of two phase I studies of multitargeted small molecule tyrosine kinase inhibitor XL647 with an intermittent and continuous dosing schedule in patients with advanced solid malignancies.

PURPOSE: To evaluate the safety, tolerability, and pharmacokinetics of XL647 and determine the maximum tolerated dose (MTD) of oral XL647 once-daily using intermittent or continuous dosing schedules. METHODS: Patients with advanced solid malignancies were enrolled in successive cohorts to receive escalating dose levels of oral once-daily XL647 using two different dosing schedules: 5 consecutive days of every 14-day cycle (study XL647-001) or continuously over 28-day cycles (study XL647-002). PK sampling was performed to determine Cmax, and AUC. Patients remained on study until progressive disease or unacceptable AEs. RESULTS: In XL647-001, 42 individuals were enrolled across 9 dose levels. The most frequently occurring drug-related AEs were diarrhea, nausea, rash, and fatigue. Expansion of the 4.68 mg/kg cohort to 6 patients occurred without further dose-limiting toxicities (DLTs) and this was considered the MTD. In XL647-002, 31 patients were enrolled across 5 dose levels. A DLT of grade 3 pneumonitis occurred in 1/6 patients at 300 mg, which was declared the MTD. The most common AEs included grade 1/2 rash, diarrhea, fatigue, dysgeusia, and QTc prolongation. Levels of pharmacodynamic plasma markers were not consistently changed after XL647 and no conclusions could be drawn with this limited data set. CONCLUSIONS: For oral XL647, the MTD was 4.68 mg/kg or 350 mg fixed dose when administered once-daily for 5 consecutive days of every 14-day cycle and was 300 mg when administered once-daily continuously. XL647 was well tolerated at doses up to the MTD.

Cabazitaxel is more active than first-generation taxanes in ABCB1(+) cell lines due to its reduced affinity for P-glycoprotein.

PURPOSE: The primary aim of this study was to determine cabazitaxel's affinity for the ABCB1/P-glycoprotein (P-gp) transporter compared to first-generation taxanes. METHODS: We determined the kinetics of drug accumulation and retention using [14C]-labeled taxanes in multidrug-resistant (MDR) cells. In addition, membrane-enriched fractions isolated from doxorubicin-selected MES-SA/Dx5 cells were used to determine sodium orthovanadate-sensitive ATPase stimulation after exposure to taxanes. Custom [3H]-azido-taxane analogues were synthesized for the photoaffinity labeling of P-gp. RESULTS: The maximum intracellular drug concentration was achieved faster with [14C]-cabazitaxel (5 min) than [14C]-docetaxel (15-30 min). MDR cells accumulated twice as much cabazitaxel than docetaxel, and these levels could be restored to parental levels in the presence of the P-gp inhibitor PSC-833 (valspodar). Efflux in drug-free medium confirmed that MDR cells retained twice as much cabazitaxel than docetaxel. There was a strong association (r2 = 0.91) between the degree of taxane resistance conferred by P-gp expression and the accumulation differences observed with the two taxanes. One cell model expressing low levels of P-gp was not cross-resistant to cabazitaxel while demonstrating modest resistance to docetaxel. Furthermore, there was a 1.9 × reduction in sodium orthovanadate-sensitive ATPase stimulation resulting from treatment with cabazitaxel compared to docetaxel. We calculated a dissociation constant (Kd) value of 1.7 µM for [3H]-azido-docetaxel and ~ 7.5 µM for [3H]-azido-cabazitaxel resulting in a 4.4 × difference in P-gp labeling, and cold docetaxel was a more effective competitor than cabazitaxel. CONCLUSION: Our studies confirm that cabazitaxel is more active in ABCB1(+) cell models due to its reduced affinity for P-gp compared to docetaxel.

Reannotation and Analysis of Clinical and Chemotherapy Outcomes in the Ovarian Data Set From The Cancer Genome Atlas.

PURPOSE: The ovarian cancer data set from The Cancer Genome Atlas integrates genomic and proteomic data with clinical annotations based on chart abstractions. We aimed to develop an algorithm to create a matching, more accessible clinical data set cataloging time to treatment failure (TTF) of sequential lines of treatment in patients with serous ovarian cancers. MATERIALS AND METHODS: The master data set of 587 patients with serous ovarian cancer was condensed into a more homogeneous and clinically relevant population comprised of high-risk patients with both grade 3 cancers and stage III or IV disease, resulting in a subgroup of 450 patients. We quantified the TTF of different lines of therapy as well as different therapeutic combinations by extrapolating from the time of starting one therapy to the time of starting a subsequent therapy. RESULTS: The overall survival (OS) of patients was highly related to platinum sensitivity status, with median OS times of 56.6, 27.0, and 11.6 months in patients who had platinum-sensitive, -resistant, or -refractory disease, respectively. In high-risk patients, the median TTFs were 14.8, 10.2, 5.7, and 4.1 months with the first, second, third, and fourth lines of chemotherapy, respectively. Patients with stable disease after first-line therapy had similar OS outcomes as patients with partial remissions (34.4 v 33.7 months, respectively). CONCLUSION: This new data set enhances the clinical annotation by providing exploitable chemotherapy benefit data that can now be paired with genomic and proteomic data within The Cancer Genome Atlas data. The major determinant of OS in this study was platinum sensitivity status. TTF decreased with each successive line of therapy. However, patients who achieved only stable disease with first-line therapy had OS similar to those with partial remission.

Safety and Activity of Varlilumab, a Novel and First-in-Class Agonist Anti-CD27 Antibody, in Patients With Advanced Solid Tumors.

Purpose CD27, a costimulatory molecule on T cells, induces intracellular signals that mediate cellular activation, proliferation, effector function, and cell survival upon binding to its ligand, CD70. Varlilumab is a novel, first-in-class, agonist CD27 antibody that stimulates the CD27 pathway, which results in T-cell activation and antitumor activity in tumor models. This first-in-human, dose-escalation and expansion study evaluated the safety, pharmacology, and activity of varlilumab in patients with advanced solid tumors. Methods In a 3 + 3 dose-escalation design (n = 25), patients received a single dose of varlilumab (0.1, 0.3, 1.0, 3.0, or 10 mg/kg intravenously) with a 28-day observation, followed by up to five multidose cycles (one dose per week for 4 weeks), depending on tumor response. Expansion cohorts were initiated at 3.0 mg/kg in patients with melanoma (n = 16) and renal cell carcinoma (RCC; n = 15). Primary objectives were to assess the safety and the maximum tolerated and optimal biologic doses of varlilumab. Secondary objectives were to evaluate the pharmacokinetics, pharmacodynamics, and clinical antitumor activity of varlilumab. Results Exposure to varlilumab was linear and dose proportional across dose groups. Only one patient experienced a dose-limiting toxicity-grade 3 transient asymptomatic hyponatremia at the 1.0-mg/kg dose level. Treatment-related adverse events were generally grade 1 or 2 in severity. Evidence of biologic activity consistent with CD27 stimulation-chemokine induction, T-cell stimulation, regulatory T cell depletion-was observed at all dose levels. A patient with metastatic RCC experienced a partial response (78% shrinkage, progression-free survival > 2.3 years). Eight patients experienced stable disease > 3 months, including a patient with metastatic RCC with progression-free survival of > 3.9 years. Conclusion Dose escalation of varlilumab to 10 mg/kg was well tolerated without identification of a maximum tolerated dose. Varlilumab was biologically and clinically active.

Decreased levels of baseline and drug-induced tubulin polymerisation are hallmarks of resistance to taxanes in ovarian cancer cells and are associated with epithelial-to-mesenchymal transition.

BACKGROUND: ABCB1 expression is uncommon in ovarian cancers in the clinical setting so we investigated non-MDR mechanisms of resistance to taxanes. METHODS: We established eight taxane-resistant variants from the human ovarian carcinoma cell lines A2780/1A9, ES-2, MES-OV and OVCAR-3 by selection with paclitaxel or docetaxel, with counter-selection by the transport inhibitor valspodar. RESULTS: Non-MDR taxane resistance was associated with reduced intracellular taxane content compared to parental controls, and cross-resistance to other microtubule stabilising drugs. Collateral sensitivity to depolymerising agents (vinca alkaloids and colchicine) was observed with increased intracellular vinblastine. These variants exhibited marked decreases in basal tubulin polymer and in tubulin polymerisation in response to taxane exposure. TUBB3 content was increased in 6 of the 8 variants. We profiled gene expression of the parental lines and resistant variants, and identified a transcriptomic signature with two highly significant networks built around FN1 and CDKN1A that are associated with cell adhesion, cell-to-cell signalling, and cell cycle regulation. miR-200 family members miR-200b and miR-200c were downregulated in resistant cells, associated with epithelial to mesenchymal transition (EMT), with increased VIM, FN1, MMP2 and/or MMP9. CONCLUSIONS: These alterations may serve as biomarkers for predicting taxane effectiveness in ovarian cancer and should be considered as therapeutic targets.

Chromatin-Remodeling Complex SWI/SNF Controls Multidrug Resistance by Transcriptionally Regulating the Drug Efflux Pump ABCB1.

Anthracyclines are among the most effective yet most toxic drugs used in the oncology clinic. The nucleosome-remodeling SWI/SNF complex, a potent tumor suppressor, is thought to promote sensitivity to anthracyclines by recruiting topoisomerase IIa (TOP2A) to DNA and increasing double-strand breaks. In this study, we discovered a novel mechanism through which SWI/SNF influences resistance to the widely used anthracycline doxorubicin based on the use of a forward genetic screen in haploid human cells, followed by a rigorous single and double-mutant epistasis analysis using CRISPR/Cas9-mediated engineering. Doxorubicin resistance conferred by loss of the SMARCB1 subunit of the SWI/SNF complex was caused by transcriptional upregulation of a single gene, encoding the multidrug resistance pump ABCB1. Remarkably, both ABCB1 upregulation and doxorubicin resistance caused by SMARCB1 loss were dependent on the function of SMARCA4, a catalytic subunit of the SWI/SNF complex. We propose that residual SWI/SNF complexes lacking SMARCB1 are vital determinants of drug sensitivity, not just to TOP2A-targeted agents, but to the much broader range of cancer drugs effluxed by ABCB1. Cancer Res; 76(19); 5810-21. ©2016 AACR.

A first-in-human phase I study to evaluate the MEK1/2 inhibitor, cobimetinib, administered daily in patients with advanced solid tumors.

Objective Cobimetinib, a MEK1/2 inhibitor, was administered to patients with advanced solid tumors to assess safety, pharmacokinetics, pharmacodynamics, and anti-tumor activity. Methods For dose-escalation, a 3 + 3 design was used. Oral cobimetinib was administered once daily on a 21-day on/7-day off (21/7) or a 14-day on/14-day off (14/14) schedule. Serial plasma samples were collected for pharmacokinetic (PK) analysis on Day 1 and at steady state. In expansion stages, patients with RAS or RAF mutant tumors were treated at the maximum tolerated dose (MTD) of the 21/7 or 14/14 schedule. Results Ninety-seven patients received cobimetinib. In the 21/7 dose escalation, 36 patients enrolled in 8 cohorts (0.05 mg/kg-80 mg). Dose-limiting toxicities (DLTs) were Grade 4 hepatic encephalopathy, Grade 3 diarrhea, and Grade 3 rash. In the 14/14 dose escalation, 20 patients enrolled in 4 cohorts (60-125 mg). DLTs were Grade 3 rash and Grade 3 blurred vision associated with presence of reversible subretinal fluid. The MTD was 60 mg on 21/7 schedule and 100 mg on 14/14 schedule. Cobimetinib PK showed dose-proportional increases in exposure. The most frequent adverse events attributed to cobimetinib were diarrhea, rash, fatigue, edema, nausea, and vomiting. In patients treated at the 60-mg (21/7) or 100-mg (14/14) dose, one unconfirmed complete response and 6 confirmed partial responses were observed. All responses occurred in melanoma patients; 6 harbored the BRAF(V600E) mutation. Conclusions Cobimetinib is generally well tolerated and durable responses were observed in BRAF(V600E) mutant melanoma patients. Evaluation of cobimetinib in combination with other therapies is ongoing.

Cancer Control in Central and Eastern Europe: Current Situation and Recommendations for Improvement.

: The incidence of many cancers is higher in Western European (WE) countries, but mortality is frequently higher in Central and Eastern European (CEE) countries. A panel of oncology leaders from CEE countries participating in the South Eastern European Research Oncology Group (SEEROG) was formed in 2015, aiming to analyze the current status and trends of oncology care in CEE and to propose recommendations leading to improved care and outcomes. The SEEROG panel, meeting during the 11th Central European Oncology Congress, proposed the following: (a) national cancer control plans (NCCPs) required in all CEE countries, defining priorities in cancer care, including finance allocation considering limited health care budgets; (b) national cancer registries, describing in detail epidemiological trends; (c) efforts to strengthen comprehensive cancer centers; (d) that multidisciplinary care should be mandated by the NCCPs; (e) that smaller hospitals should be connected to multidisciplinary tumor boards via the Internet, providing access to specialized expertise; (f) nationwide primary prevention programs targeting smoking, obesity, and alcohol consumption and centrally evaluated secondary prevention programs for cervical, colorectal, and breast cancers; (g) prioritize education for all involved in cancer care, including oncology nurses, general practitioners, and palliative care providers; (h) establish outpatient care in day hospitals to reduce costs associated with the current inpatient model of care in CEE countries and to improve patients' quality of life; (i) long-term pharmacoeconomic evaluations of new therapies in CEE countries; (j) increase national oncology budgets in view of the higher mortality rates in CEE compared with WE countries; and (k) CEE countries urgently need help from the European Union to increase and monitor overall investment in cancer care. IMPLICATIONS FOR PRACTICE: Significant differences in cancer incidence and mortality have been observed between European countries. While the incidence of many cancer types is higher in Western European (WE) countries, the mortality is generally higher in Central and Eastern Europe (CEE). The primary purpose of this review was to describe the current status and trends of oncology care in the CEE region, to raise awareness among physicians, regulators, and payers, and to propose the most needed changes in order to make the oncology care in CEE closer to the WE standards.

Single Gene Prognostic Biomarkers in Ovarian Cancer: A Meta-Analysis.

PURPOSE: To discover novel prognostic biomarkers in ovarian serous carcinomas. METHODS: A meta-analysis of all single genes probes in the TCGA and HAS ovarian cohorts was performed to identify possible biomarkers using Cox regression as a continuous variable for overall survival. Genes were ranked by p-value using Stouffer's method and selected for statistical significance with a false discovery rate (FDR) <.05 using the Benjamini-Hochberg method. RESULTS: Twelve genes with high mRNA expression were prognostic of poor outcome with an FDR <.05 (AXL, APC, RAB11FIP5, C19orf2, CYBRD1, PINK1, LRRN3, AQP1, DES, XRCC4, BCHE, and ASAP3). Twenty genes with low mRNA expression were prognostic of poor outcome with an FDR <.05 (LRIG1, SLC33A1, NUCB2, POLD3, ESR2, GOLPH3, XBP1, PAXIP1, CYB561, POLA2, CDH1, GMNN, SLC37A4, FAM174B, AGR2, SDR39U1, MAGT1, GJB1, SDF2L1, and C9orf82). CONCLUSION: A meta-analysis of all single genes identified thirty-two candidate biomarkers for their possible role in ovarian serous carcinoma. These genes can provide insight into the drivers or regulators of ovarian cancer and should be evaluated in future studies. Genes with high expression indicating poor outcome are possible therapeutic targets with known antagonists or inhibitors. Additionally, the genes could be combined into a prognostic multi-gene signature and tested in future ovarian cohorts.