Phase Ib clinical trial of the anti-frizzled antibody vantictumab (OMP-18R5) plus paclitaxel in patients with locally advanced or metastatic HER2-negative breast cancer.

PURPOSE: Vantictumab is a monoclonal antibody that binds to frizzled (FZD) receptors and inhibits canonical WNT signaling. This phase Ib dose escalation study enrolled patients with locally recurrent or metastatic HER2-negative breast cancer who were treated with weekly paclitaxel in combination with escalating doses of vantictumab. METHODS: Patients were enrolled in dose escalation cohorts treated with weekly paclitaxel 90 mg/m2 on days 1, 8 and 15 in combination with vantictumab 3.5-14 mg/kg days 1 and 15 or 3-8 mg/kg day 1 of every 28-day cycle. Primary endpoints were safety, dose-limiting toxicities (DLTs). Secondary endpoints included pharmacokinetics, efficacy and an exploratory biomarker analysis. RESULTS: Forty-eight female patients with a mean age of 54 were enrolled. The majority (66.6%) received prior chemotherapy for recurrent or metastatic disease; 45.8% were hormone receptor (HR)-positive, HER2-negative and 54.2% triple-negative. The most frequent adverse events related to any study treatment were nausea (54.2%), alopecia (52.1%), fatigue (47.9%), and peripheral neuropathy (43.8%). No DLTs occurred; however, 6 patients experienced fractures outside of the DLT window. The overall response rate was 31.3% and the clinical benefit rate was 68.8%. A 6-gene WNT pathway signature showed significant association with progression-free survival (PFS) and overall survival (OS) for the biomarker high versus biomarker low groups (PFS: p = 0.029 and OS: p = 0.00045, respectively). CONCLUSIONS: The combination of vantictumab and weekly paclitaxel was generally well tolerated with promising efficacy; however, the incidence of fractures limits future clinical development of this particular WNT inhibitor in metastatic breast cancer. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov registration: NCT01973309.

Phase Ib study of avadomide (CC-122) in combination with rituximab in patients with relapsed/refractory diffuse large B-cell lymphoma and follicular lymphoma.

The multicenter, phase Ib CC-122-DLBCL-001 dose-expansion study (NCT02031419) explored the cereblon E3 ligase modulator (CELMoD) agent avadomide (CC-122) plus rituximab in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL). Patients received avadomide 3 mg/day 5 days on/2 days off plus rituximab 375 mg/m2 on day 8 of cycle 1, day 1 of cycles 2 through 6, and day 1 of every third subsequent cycle for 2 years. Primary endpoints were safety and tolerability; preliminary efficacy was a secondary endpoint. A total of 68 patients were enrolled (DLBCL [n = 27], FL [n = 41; 31 lenalidomide-naïve, 10 lenalidomide-treated]). Median age was 62 years (range, 33-84 years), and patients had received a median of 3 (range, 1-8) prior regimens. Among patients with DLBCL, 66.7% had primary refractory disease (partial response or less to initial therapy). Among patients with FL, 65.9% were rituximab-refractory at study entry and 10.0% were lenalidomide-refractory. The most common any-grade avadomide-related adverse events (AEs) were neutropenia (63.2%), infections/infestations (23.5%), fatigue (22.1%), and diarrhea (19.1%). The most common grade 3/4 avadomide-related AEs were neutropenia (55.9%) infections/infestations (8.8%), and febrile neutropenia (7.4%). In patients with DLBCL, overall response rate (ORR) was 40.7% and median duration of response (mDOR) was 8.0 months. In patients with FL, ORR was 80.5% and mDOR was 27.6 months; response rates were similar in lenalidomide-naïve and -treated patients. Avadomide plus rituximab was well tolerated, and preliminary antitumor activity was observed in patients with R/R DLBCL and FL, including subgroups with typically poor outcomes. These results support further investigation of novel CELMoD agents in combination with rituximab in R/R DLBCL and FL.

Phase Ib study of combinations of avadomide (CC-122), CC-223, CC-292, and rituximab in patients with relapsed/refractory diffuse large B-cell lymphoma.

There is a need for additional treatment options for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) who do not benefit from available therapies. We examined combinations of the cereblon E3 ligase modulator (CELMoD) agent avadomide (CC-122), the selective, ATP-competitive mammalian target of rapamycin kinase inhibitor CC-223, and the potent, selective, covalent Bruton tyrosine kinase inhibitor CC-292 in patients with relapsed/refractory (R/R) DLBCL. In the multicenter, phase Ib CC-122-DLBCL-001 study (NCT02031419), the dose-escalation portion explored combinations of CC-122, CC-223, and CC-292 administered as doublets or triplets with rituximab in patients with chemorefractory DLBCL. Primary endpoints were safety, tolerability, and dose-limiting toxicities; additional endpoints included pharmacokinetics, pharmacodynamics, biomarkers, and preliminary efficacy. As of December 1, 2017, 106 patients were enrolled across four cohorts. The median age was 65 years (range 24-84 years), and patients had a median of 3 (range 1-10) prior to regimens. A total of 101 patients (95.3%) discontinued, most commonly due to disease progression (49.1%). The most common any-grade adverse events (AEs) across treatment arms were gastrointestinal and hematologic; the most common grade 3/4 AEs were hematologic. CC-122 was well tolerated, with no unexpected safety concerns. Preliminary efficacy was observed in three of four treatment arms. CC-122 plus rituximab was considered suitable for dose expansion, whereas CC-223 and CC-292 combinations were associated with enhanced toxicity and/or insufficient improvement in responses. CC-122 plus rituximab was well tolerated, with preliminary antitumor activity in patients with R/R DLBCL. This innovative study demonstrates the feasibility of assessing the tolerability and preliminary efficacy of novel combinations utilizing a multi-arm dose-finding design.

Phase Ib Study of Wnt Inhibitor Ipafricept with Gemcitabine and nab-paclitaxel in Patients with Previously Untreated Stage IV Pancreatic Cancer.

PURPOSE: The recombinant fusion protein ipafricept blocks Wnt signaling, and in combination with gemcitabine and nab-paclitaxel caused tumor regression in xenografts. This phase Ib study evaluated the combination of ipafricept with nab-paclitaxel + gemcitabine in patients with untreated metastatic pancreatic adenocarcinoma (mPDAC). PATIENTS AND METHODS: Dose escalation started with standard dose nab-paclitaxel + gemcitabine and ipafricept (3.5 mg/kg days 1, 15). Because of fragility fractures seen with different anti-Wnt agents, following cohorts had ≥6 patients treated with ipafricept 3 to 5 mg/kg on day 1, and included bone marker monitoring and prophylactic bisphosphonates as indicated. On the basis of preclinical data, sequential dosing was evaluated in cohort 4 (ipafricept day 1 followed nab-paclitaxel + gemcitabine day 3). Objectives included safety, MTD, recommended phase II dose, pharmacokinetics, immunogenicity, pharmacodynamics, and efficacy. RESULTS: A total of 26 patients were enrolled, five in cohort 1 and seven each in cohorts 2-4. ipafricept-related adverse events (AEs) of any grade included fatigue, nausea, vomiting, anorexia, and pyrexia. ipafricept-related AEs grade ≥3 included two events of aspartate aminotransferase elevation, and one each of nausea, rash, vomiting, and leucopenia. No dose-limiting toxicities or fragility fractures were observed. Nine patients (34.6%) had partial response, 12 (46.2%) stable disease as best response, with clinical benefit rate of 81%. Median progression-free survival was 5.9 m [95% confidence interval (CI), 3.4-18.4], median overall survival was 9.7 m (95% CI, 7.0-14). The study was terminated by the sponsor due to bone-related toxicity within this therapeutic program and concerns for commercial viability. One patient remains on therapy under compassionate use. CONCLUSIONS: Ipafricept can be administered with nab-paclitaxel + gemcitabine with reasonable tolerance. Wnt pathway remains a therapeutic target of interest in mPDAC.

Avadomide plus obinutuzumab in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (CC-122-NHL-001): a multicentre, dose escalation and expansion phase 1 study.

BACKGROUND: Avadomide (CC-122) is a novel oral cereblon-modulating agent with promising activity in non-Hodgkin lymphoma. We aimed to examine the safety and preliminary activity of avadomide plus obinutuzumab in patients with relapsed or refractory non-Hodgkin lymphoma. METHODS: CC-122-NHL-001 was a phase 1b dose escalation and expansion study at eight sites in France, Italy, and the Netherlands. Eligible patients (aged ≥18 years) had histologically confirmed CD20-positive relapsed or refractory non-Hodgkin lymphoma, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had received previous treatment. In the dose expansion phase, only patients with previously treated relapsed or refractory follicular lymphoma (grade 1, 2, or 3a) were included. Avadomide was administered in escalating doses and two formulations: active pharmaceutical ingredient in capsule in 1·0 mg, 2·0 mg, 3·0 mg, and 4·0 mg doses and as formulated capsules in 3·0 mg and 4·0 mg doses orally once daily on days 1-5 followed by 2 days off (5-7-day schedule) every week of each 28-day cycle. Obinutuzumab 1000 mg was administered intravenously on days 2, 8, and 15 of cycle 1 and day 1 of cycles 2-8. Primary objectives were to determine the safety and tolerability, the non-tolerated dose, maximum tolerated dose, and recommended phase 2 dose (RP2D). All patients who received treatment were included in the safety analyses. Efficacy-evaluable patients completed at least one cycle of treatment and had baseline and at least one post-baseline assessment. The study is registered with ClinicalTrials.gov, NCT02417285 and EudraCT 2014-003333-26, and is ongoing. FINDINGS: Between June 24, 2015, and Dec 5, 2018, 73 patients were enrolled and treated; 19 had diffuse large B-cell lymphoma, 53 follicular lymphoma, and one marginal zone lymphoma. Median follow-up was 253 days (IQR 127-448). The median number of previous anticancer regimens was three (IQR 2-4). The maximum tolerated dose and non-tolerated dose were not reached in the dose escalation phase. On the basis of safety and pharmacokinetic-pharmacodynamic data, the avadomide RP2D was established as 3·0 mg as formulated capsules on a 5-7-day schedule in combination with 1000 mg of obinutuzumab. Patients enrolled in the expansion cohort received the established RP2D of avadomide. Across all doses, three patients had dose-limiting toxicities; one patient treated at the RP2D had dose-limiting toxicity (grade 3 sepsis). The most common adverse events of grade 3 and above were neutropenia (41 [56%] of 73) and thrombocytopenia (17 [23%] of 73). 34 (47%) patients had serious adverse events, which were considered to be avadomide-related in 23 (32%) of 73 patients and obinutuzumab-related in 20 (27%) of 73 patients. Two treatment-related deaths occurred, one owing to tumour flare and one from acute myeloid leukaemia after study discontinuation. INTERPRETATION: Avadomide plus obinutuzumab has a manageable toxicity, being a tolerable treatment option for most patients. Although the prespecified threshold for activity was not met in the trial, we believe that the preliminary antitumour activity of cereblon modulators plus next-generation anti-CD20 antibodies in heavily pretreated relapsed or refractory non-Hodgkin lymphoma warrants further investigation as a chemotherapy-free option in this setting. FUNDING: Celgene Corporation.

A First-in-Human Phase I Study of the Anticancer Stem Cell Agent Ipafricept (OMP-54F28), a Decoy Receptor for Wnt Ligands, in Patients with Advanced Solid Tumors.

Purpose: Wnt signaling is implicated in tumor cell dedifferentiation and cancer stem cell function. Ipafricept (OMP-54F28) is a first-in-class recombinant fusion protein with the extracellular part of human frizzled 8 receptor fused to a human IgG1 Fc fragment that binds Wnt ligands. This trial evaluated ipafricept in patients with solid tumors.Experimental design: A 3+3 design was used; ipafricept was given intravenously every 3 weeks. The objectives were determination of dose-limiting toxicities (DLTs), recommended phase 2 dose (RP2D), safety, pharmacokinetics (PK), immunogenicity, pharmacodynamics (PD), and preliminary efficacy.Results: 26 patients were treated in seven dose-escalation cohorts (0.5, 1, 2.5, 5, 10, 15, and 20 mg/kg). No further dose escalation was pursued as PK modeling indicated that the target efficacious dose was reached at 10 mg/kg, and fragility fractures occurred at 20 mg/kg. Most common related grade 1 and 2 adverse events (AEs; ≥20% of patients) were dysgeusia, decreased appetite, fatigue, and muscle spasms. Ipafricept-related grade 3 TEAEs included hypophosphatemia and weight decrease (1 subject each, 3.8%). Ipafricept half-life was ∼4 days and had low incidence of antidrug antibody formation (7.69%) with no impact on drug exposure. Six patients had ß-C-terminal telopeptide (ß-CTX) doubling from baseline, which was reversible. PD modulation of Wnt pathway genes in hair follicles occurred ≥2.5 mg/kg. Two desmoid tumor and a germ cell cancer patient experienced stable disease for >6 months.Conclusions: Ipafricept was well tolerated, with RP2D of 15 mg/kg Q3W. Prolonged SD was noted in desmoid tumor and germ cell cancer patients. Clin Cancer Res; 23(24); 7490-7. ©2017 AACR.

Matrix-independent activation of phosphatidylinositol 3-kinase, Stat3, and cyclin A-associated Cdk2 Is essential for anchorage-independent growth of v-Ros-transformed chicken embryo fibroblasts.

The question remains open whether the signaling pathways shown to be important for growth and transformation in adherent cultures proceed similarly and play similar roles for cells grown under anchorage-independent conditions. Chicken embryo fibroblasts (CEF) infected with the avian sarcoma virus UR2, encoding the oncogenic receptor protein-tyrosine kinase (RPTK) v-Ros, or with two of its transformation-impaired mutants were grown in nonadherent conditions in methylcellulose (MC)-containing medium, and the signaling functions essential for Ros-induced anchorage-independent growth were analyzed. We found that the overall tyrosine phosphorylation of cellular proteins in CEF transformed by v-Ros or by two oncogenic nonreceptor protein-tyrosine kinases (PTKs), v-Src and v-Yes, was dramatically reduced in nonadherent conditions compared with that in adherent conditions, indicating that cell adhesion to the extracellular matrix plays an important role in efficient substrate phosphorylation by these constitutively activated PTKs. The UR2 transformation-defective mutants were differentially impaired compared with UR2 in the activation of phosphatidylinositol 3-kinase (PI 3-kinase) and Stat3 in nonadherent conditions. Consistently, the constitutively activated mutants of PI 3-kinase and Stat3 rescued the ability of the UR2 mutants to promote anchorage-independent growth. Conversely, dominant negative mutants of PI 3-kinase and Stat3 inhibited UR2-induced anchorage-independent growth. UR2-infected CEF grown in nonadherent conditions displayed faster cell cycle progression than the control or the UR2 mutant-infected cells, and this appeared to correlate with a PI 3-kinase-dependent increase in cyclin A-associated Cdk2 activity. Treatment of UR2-infected cells with Cdk2 inhibitors led to the loss of the anchorage-independent growth-promoting activity of UR2. In conclusion, we have adopted an experimental system enabling us to study the signaling pathways in cells grown under anchorage-independent conditions and have identified matrix-independent activation of PI 3-kinase and Stat3 signaling functions, as well as the PI 3-kinase-dependent increase of cyclin A-associated Cdk2 kinase activity, to be critical for the Ros-PTK-induced anchorage-independent growth.

The role of phosphatidylinositol 3-kinase, rho family GTPases, and STAT3 in Ros-induced cell transformation.

Using loss-of-function mutants of Ros and inducible epidermal growth factor receptor-Ros chimeras we investigated the role of various signaling pathways in Ros-induced cell transformation. Inhibition of the mitogen-activated protein kinase (MAPK) pathway with the MEK (MAP/extracellular signal-regulated kinase kinase) inhibitor PD98059 had little effect on the Ros-induced monolayer and anchorage-independent growth of chicken embryo fibroblasts and NIH3T3 cells even though more than 70% of the MAPK was inhibited. In contrast, inhibiting the phosphatidylinositol 3-kinase (PI3K) pathway with the drug LY294002, a dominant negative mutant of PI3K, Deltap85, or the phosphatidylinositol phosphatase PTEN (phosphatase and tensin homologue deleted in chromosome ten) resulted in a dramatic reduction of v-Ros- and epidermal growth factor receptor-Ros-promoted anchorage-independent growth of chicken embryo fibroblasts and NIH3T3 cells, respectively. Parallel and downstream components of PI3K signaling such as the Rho family GTPases (Rac, Rho, Cdc42) and the survival factor Akt were all shown to contribute to Ros-induced anchorage-independent growth, although Rac appeared to be less important for Ros-induced colony formation in NIH3T3 cells. Furthermore, the transformation-attenuated v-Ros mutants F419 and DI could be complemented by constitutively active mutants of PI3K and Akt. Finally, we found that overexpressing a constitutively active mutant of STAT3 (STAT3C) conferred a resistance to the inhibition of Ros-induced anchorage-independent growth by LY294002, suggesting a possible overlap of functions between PI3K and STAT3 signaling in mediating Ros-induced anchorage-independent growth.