Randomized phase II trial of farletuzumab plus chemotherapy versus placebo plus chemotherapy in low CA-125 platinum-sensitive ovarian cancer.

OBJECTIVE: The primary purpose of this study was to determine if farletuzumab, an antifolate receptor-α monoclonal antibody, improved progression-free survival (PFS) versus placebo when added to standard chemotherapy regimens in patients with platinum-sensitive recurrent ovarian cancer (OC) in first relapse (platinum-free interval: 6-36 months) with low cancer antigen 125 (CA-125) levels. METHODS: Eligibility included CA-125 ≤ 3 x upper limit of normal (ULN, 105 U/mL), high-grade serous, platinum-sensitive recurrent OC, previous treatment with debulking surgery, and first-line platinum-based chemotherapy with 1st recurrence between 6 and 36 months since frontline platinum-based treatment. Patients received investigator's choice of either carboplatin (CARBO)/paclitaxel (PTX) every 3 weeks or CARBO/pegylated liposomal doxorubicin (PLD) every 4 weeks x6 cycles in combination with either farletuzumab [5 mg/kg weekly] or placebo randomized in a 2:1 ratio. Maintenance treatment with farletuzumab (5 mg/kg weekly) or placebo was given until disease progression or intolerance. RESULTS: 214 patients were randomly assigned to farletuzumab+chemotherapy (142 patients) versus placebo+chemotherapy (72 patients). The primary efficacy endpoint, PFS, was not significantly different between treatment groups (1-sided α = 0.10; p-value = 0.25; hazard ratio [HR] = 0.89, 80% confidence interval [CI]: 0.71, 1.11), a median of 11.7 months (95% CI: 10.2, 13.6) versus 10.8 months (95% CI: 9.5, 13.2) for farletuzumab+chemotherapy and placebo+chemotherapy, respectively. No new safety concerns were identified with the combination of farletuzumab+chemotherapy. CONCLUSIONS: Adding farletuzumab to standard chemotherapy does not improve PFS in patients with OC who were platinum-sensitive in first relapse with low CA-125 levels. Folate receptor-α expression was not measured in this study. (Clinical Trial Registry NCT02289950).

A phase 1 and randomized controlled phase 2 trial of the safety and efficacy of the combination of gemcitabine and docetaxel with ontuxizumab (MORAb-004) in metastatic soft-tissue sarcomas.

BACKGROUND: Ontuxizumab, a humanized monoclonal antibody, targets endosialin (tumor endothelial marker 1 [TEM-1] or CD248), which is expressed on sarcoma cells and is believed to be involved in tumor angiogenesis. This is the first trial to evaluate ontuxizumab in patients with sarcoma. METHODS: Part 1 was an open-label, dose-finding, safety lead-in: 4, 6, or 8 mg/kg with gemcitabine and docetaxel (G/D; 900 mg/m2 gemcitabine on days 1 and 8 and 75 mg/m2 docetaxel on day 8). In part 2, patients were randomized in a double-blind fashion in 2:1 ratio to ontuxizumab (8 mg/kg) or a placebo with G/D. Randomization was stratified by 4 histological cohorts. RESULTS: In part 2 with 209 patients, no significant difference in progression-free survival between ontuxizumab plus G/D (4.3 months; 95% confidence interval [CI], 2.7-6.3 months) and the placebo plus G/D (5.6 months; 95% CI, 2.6-8.3 months) was observed (P = .67; hazard ratio [HR], 1.07; 95% CI, 0.77-1.49). Similarly, there was no significant difference in median overall survival between the 2 groups: 18.3 months for the ontuxizumab plus G/D group (95% CI, 16.2-21.1 months) and 21.1 months for the placebo plus G/D group (95% CI, 14.2 months to not reached; P = .32; HR, 1.23; 95% CI, 0.82-1.82). No significant differences between the treatment groups occurred for any efficacy parameter by sarcoma cohort. The combination of ontuxizumab plus G/D was generally well tolerated. CONCLUSIONS: Ontuxizumab plus G/D showed no enhanced activity over chemotherapy alone in soft-tissue sarcomas, whereas the safety profile of the combination was consistent with G/D alone.

A phase 2 study of ontuxizumab, a monoclonal antibody targeting endosialin, in metastatic melanoma.

Objectives Ontuxizumab (MORAB-004) is a first-in-class monoclonal antibody that interferes with endosialin function, which is important in tumor stromal cell function, angiogenesis, and tumor growth. This Phase 2 study evaluated the 24-week progression-free survival (PFS) value, pharmacokinetics, and tolerability of 2 doses of ontuxizumab in patients with metastatic melanoma. Patients and methods Patients with metastatic melanoma and disease progression after receiving at least 1 prior systemic treatment were randomized to receive ontuxizumab (2 or 4 mg/kg) weekly, without dose change, until disease progression. Results Seventy-six patients received at least 1 dose of ontuxizumab (40 received 2 mg/kg, 36 received 4 mg/kg). The primary endpoint, 24-week PFS value, was 11.4% (95% Confidence Interval [CI]: 5.3%-19.9%) for all patients (13.5% for 2 mg/kg and 8.9% for 4 mg/kg). The median PFS for all patients was 8.3 weeks (95% CI: 8.1-12.3 weeks). One patient receiving 4 mg/kg had a partial response, as measured by Response Evaluation Criteria in Solid Tumors v1.1. Twenty-seven of 66 response evaluable patients (40.9%) had stable disease. The median overall survival was 31.0 weeks (95% CI: 28.3-44.0 weeks). The most common adverse events overall were headache (55.3%), fatigue (48.7%), chills (42.1%), and nausea (36.8%), mostly grade 1 or 2. Conclusions Ontuxizumab at both doses was well tolerated. The 24-week PFS value was 11.4% among all ontuxizumab-treated patients. The overall response rate was 3.1% at the 4 mg/kg dose, with clinical benefit achieved in 42.4% of response evaluable patients. Efficacy of single-agent ontuxizumab at these doses in melanoma was low.

Phase 1b safety study of farletuzumab, carboplatin and pegylated liposomal doxorubicin in patients with platinum-sensitive epithelial ovarian cancer.

OBJECTIVE: Farletuzumab is a humanized monoclonal antibody that binds to folate receptor alpha, over-expressed in epithelial ovarian cancer (EOC) but largely absent in normal tissue. Previously, carboplatin plus pegylated liposomal doxorubicin showed superior progression-free survival and an improved therapeutic index compared with carboplatin/paclitaxel in relapsed platinum-sensitive EOC. This study assessed safety of farletuzumab/carboplatin/pegylated liposomal doxorubicin in women with platinum-sensitive recurrent EOC. METHODS: This multicenter, single-arm study enrolled patients with platinum-sensitive EOC in first or second relapse for treatment with weekly farletuzumab 2.5mg/kg plus carboplatin AUC5-6 and pegylated liposomal doxorubicin 30mg/m(2) every 4weeks for 6cycles. Subsequently, maintenance with single-agent farletuzumab 2.5mg/kg once weekly or farletuzumab 7.5mg/kg once every three weeks continued until progression. The primary objective was to assess the safety of farletuzumab/carboplatin/pegylated liposomal doxorubicin. RESULTS: Fifteen patients received a median of 12.0cycles (range, 3-26) of farletuzumab as combination therapy or maintenance, for a median of 45.0weeks (range 9-95). Farletuzumab/carboplatin/pegylated liposomal doxorubicin was generally well tolerated, with no farletuzumab-related grades 3-4 adverse events. The most commonly reported adverse events were associated with combination chemotherapy: fatigue (73.3%), nausea (46.7%), and neutropenia (40%). Ten patients had grade ≥3 adverse events, most frequently neutropenia and fatigue. No cardiac toxicity was seen. Best overall responses (RECIST) were a complete response for one patient, partial responses for 10 patients, and stable disease for four patients. CONCLUSIONS: Farletuzumab plus carboplatin/pegylated liposomal doxorubicin in women with platinum-sensitive EOC demonstrated a safety profile consistent with that of carboplatin plus pegylated liposomal doxorubicin.

Farletuzumab (a monoclonal antibody against folate receptor alpha) in relapsed platinum-sensitive ovarian cancer.

OBJECTIVE: Farletuzumab is a humanized monoclonal antibody to folate receptor-α, which is over-expressed in most epithelial ovarian cancers but largely absent on normal tissue. We evaluated clinical activity of farletuzumab, alone and combined with chemotherapy, in women with first-relapse, platinum-sensitive ovarian, fallopian tube and primary peritoneal cancers. METHODS: Fifty-four eligible subjects received open-label farletuzumab weekly, single agent or combined with carboplatin (AUC5-6) and taxane (paclitaxel 175 mg/m(2) or docetaxel 75 mg/m(2)), every 21 days for 6 cycles, followed by farletuzumab maintenance until progression. Twenty-eight subjects with asymptomatic CA125 relapse received single-agent farletuzumab and could receive platinum/taxane chemotherapy plus farletuzumab after single-agent progression. Twenty-six subjects with symptomatic relapse entered the combination arm directly; 21 subjects entered after single agent. Primary endpoints included normalized CA125 and Overall Response Rate (ORR). Duration of each subject's second progression-free interval (PFI2) was compared with her own first response interval (PFI1). RESULTS: Farletuzumab was well-tolerated as single agent, without additive toxicity when administered with chemotherapy. Of 47 subjects who received farletuzumab with chemotherapy, 38 (80.9%) normalized CA125. In 9/42 (21%) evaluable subjects, PFI2 was≥PFI1, better than the historical rate (3%). There was a high response rate among subjects with PFI1 <12 months (75%), comparable to that in subjects with PFI1 ≥12 months (84%). Complete or partial ORR was 75% with combination therapy. CONCLUSION: Based on this study, farletuzumab with carboplatin and taxane may enhance the response rate and duration of response in platinum-sensitive ovarian cancer patients with first relapse after remission of 6-18 months.

Allelic imbalance in BRCA1 and BRCA2 gene expression is associated with an increased breast cancer risk.

The contribution of BRCA1 and BRCA2 to familial and non-familial forms of breast cancer has been difficult to accurately estimate because of the myriad of potential genetic and epigenetic mechanisms that can ultimately influence their expression and involvement in cellular activities. As one of these potential mechanisms, we investigated whether allelic imbalance (AI) of BRCA1 or BRCA2 expression was associated with an increased risk of developing breast cancer. By developing a quantitative approach utilizing allele-specific real-time PCR, we first evaluated AI caused by nonsense-mediated mRNA decay in patients with frameshift mutations in BRCA1 and BRCA2. We next measured AI for BRCA1 and BRCA2 in lymphocytes from three groups: familial breast cancer patients, non-familial breast cancer patients and age-matched cancer-free females. The AI ratios of BRCA1, but not BRCA2, in the lymphocytes from familial breast cancer patients were found to be significantly increased as compared to cancer-free women (BRCA1: 0.424 versus 0.211, P = 0.00001; BRCA2: 0.206 versus 0.172, P = 0.38). Similarly, the AI ratios were greater for BRCA1 and BRCA2 in the lymphocytes of non-familial breast cancer cases versus controls (BRCA1: 0.353, P = 0.002; BRCA2: 0.267, P = 0.03). Furthermore, the distribution of under-expressed alleles between cancer-free controls and familial cases was significantly different for both BRCA1 and BRCA2 gene expression (P < 0.02 and P < 0.02, respectively). In conclusion, we have found that AI affecting BRCA1 and to a lesser extent BRCA2 may contribute to both familial and non-familial forms of breast cancer.

A Randomized, Double-Blind, Placebo-Controlled Phase II Study of the Efficacy and Safety of Monotherapy Ontuxizumab (MORAb-004) Plus Best Supportive Care in Patients with Chemorefractory Metastatic Colorectal Cancer.

Purpose: The purpose of this study was to evaluate the safety and efficacy of ontuxizumab (MORAb-004), a monoclonal antibody that interferes with endosialin (tumor endothelial marker-1) function, in patients with chemorefractory metastatic colorectal cancer and to identify a responsive patient population based on biomarkers.Experimental Design: This was a randomized, double-blind, placebo-controlled, phase II study. Patients were randomly assigned in a 2:1 ratio to receive weekly intravenous ontuxizumab (8 mg/kg) or placebo plus best supportive care until progression or unacceptable toxicity. Tissue and blood biomarkers were evaluated for their ability to identify a patient population that was responsive to ontuxizumab.Results: A total of 126 patients were enrolled. No significant difference between the ontuxizumab and placebo groups was evident for the primary endpoint of progression-free survival (PFS), with a median PFS of 8.1 weeks in each group (HR, 1.13; 95% confidence interval, 0.76-1.67; P = 0.53). There were no significant differences between groups for overall survival (OS) or overall response rate (ORR). The most common treatment-emergent adverse events (TEAEs) in the ontuxizumab group (vs. the placebo group, respectively) were fatigue (53.7% vs. 47.5%), nausea (39.0% vs. 35.0%), decreased appetite (34.1% vs. 27.5%), and constipation (28.0% vs. 32.5%). The most common grade 3/4 TEAE in the ontuxizumab group versus placebo was back pain (11.0% vs. 0%). No single biomarker clearly identified patients responsive to ontuxizumab.Conclusions: No benefit with ontuxizumab monotherapy compared with placebo for clinical response parameters of PFS, OS, or ORR was demonstrated. Ontuxizumab was well tolerated. Clin Cancer Res; 24(2); 316-25. ©2017 AACR.

A Randomized, Double-Blind, Placebo-Controlled, Phase III Study to Assess Efficacy and Safety of Weekly Farletuzumab in Combination With Carboplatin and Taxane in Patients With Ovarian Cancer in First Platinum-Sensitive Relapse.

PURPOSE: Farletuzumab is a humanized monoclonal antibody that binds to folate receptor-α, which is highly expressed in ovarian carcinoma and largely absent from normal tissue. Farletuzumab was investigated in a double-blind, randomized phase III study in platinum-sensitive ovarian cancer. PATIENTS AND METHODS: Eligible patients had first recurrent ovarian cancer 6-24 months following completion of platinum-taxane chemotherapy. All patients received carboplatin plus paclitaxel or docetaxel (for six cycles combined with randomly assigned test products in a 1:1:1 ratio: farletuzumab 1.25 mg/kg, farletuzumab 2.5 mg/kg, or placebo). The single-agent test product was continued weekly until disease progression. The primary end point was progression-free survival (PFS) by Response Evaluation Criteria in Solid Tumors. Additional analyses not outlined in the original protocol were prespecified in the final statistical analysis plan, including a subgroup analysis by baseline CA-125 and farletuzumab exposure levels. RESULTS: A total of 1,100 women were randomly assigned to treatment dose or placebo. PFS from the primary analysis was 9.0, 9.5, and 9.7 months for the placebo, farletuzumab 1.25 mg/kg, and farletuzumab 2.5 mg/kg groups, respectively. Neither farletuzumab group was statistically different from the placebo group (hazard ratio [HR], 0.99 [95% CI, 0.81 to 1.21] and 0.86 [95% CI, 0.70 to 1.06] for farletuzumab 1.25 mg/kg and 2.5 mg/kg group v placebo, respectively). In the prespecified subgroup, baseline CA-125 levels not more than three times the upper limit of normal (ULN) correlated with longer PFS (HR, 0.49; P = .0028) and overall survival (OS) (HR, 0.44; P = .0108) for farletuzumab 2.5 mg/kg versus placebo. Subgroup analysis of farletuzumab exposure above the median, regardless of dose, showed significantly better PFS versus placebo. The most common adverse events were those associated with chemotherapy. CONCLUSION: Neither farletuzumab dose met the study's primary PFS end point. Prespecified subgroup analyses demonstrated that patients with CA-125 levels not more than three times the ULN and patients with higher farletuzumab exposure showed superior PFS and OS compared with placebo.

A first-in-human phase I study of MORAb-004, a monoclonal antibody to endosialin in patients with advanced solid tumors.

PURPOSE: Endosialin (TEM-1, CD248) is a protein expressed on the surface of activated mesenchymal cells, including certain subsets of tumors. Preclinical models suppressing endosialin function have shown antitumor activity. A humanized monoclonal antibody, MORAb-004, was engineered to target endosialin and is the first agent in clinical development for this mesenchymal cell target. EXPERIMENTAL DESIGN: This first-in-human, open-label, phase I study recruited patients with treatment-refractory solid tumors. MORAb-004 was administered intravenously once weekly in 4-week cycles. Objectives included determination of the safety of multiple infusions of MORAb-004, identification of the maximum tolerated dose (MTD), pharmacokinetic modeling, detection of any anti-human antibody response, and assessment of objective radiographic response to therapy. RESULTS: Thirty-six patients were treated at 10 dose levels of MORAb-004, ranging from 0.0625 to 16 mg/kg. Drug-related adverse events were primarily grade 1-2 infusion toxicities. Dose-limiting toxicity of grade 3 vomiting was observed at 16 mg/kg. Eighteen of 32 evaluable patients across all doses achieved disease stability, with minor radiographic responses observed in 4 patients (pancreatic neuroendocrine, hepatocellular, and sarcoma tumor types). Pharmacokinetics showed MORAb-004 accumulation beginning at 4 mg/kg and saturable elimination beginning at 0.25 mg/kg. Exposure increased in a greater-than-dose-proportional manner with terminal half-life increasing proportionally with dose. The MTD was identified as 12 mg/kg. CONCLUSIONS: Preliminary antitumor activity was observed. Safety profile, pharmacokinetics, and early antitumor activity suggest that MORAb-004 is safe at doses up to 12 mg/kg and should be studied further for efficacy.

Inhibition of mesothelin-CA-125 interaction in patients with mesothelioma by the anti-mesothelin monoclonal antibody MORAb-009: Implications for cancer therapy.

BACKGROUND: Mesothelin, a tumor differentiation antigen highly expressed in mesothelioma and ovarian cancer, is the receptor for CA-125 (MUC 16) and this interaction may play a role in tumor metastasis. MORAb-009 is a chimeric anti-mesothelin monoclonal antibody. METHODS: Twenty-four patients with mesothelin expressing cancers were treated on a phase I study of MORAb-009 administered as an intravenous infusion (12.5-400mg/m(2)) weeklyx4 doses with 2 weeks off before the next cycle. This report summarizes the effect of MORAb-009 on serum CA-125 kinetics in the eight patients with mesothelioma who had CA-125 levels measured before and at different time-points following therapy. RESULTS: MORAb-009 treatment led to a marked increase in serum CA-125 levels in all patients including those without elevated CA-125 levels before therapy. The increase in CA-125 levels was not due to disease progression since CA-125 levels decreased rapidly after stopping MORAb-009 therapy. No patients had signs of peritoneal or pleural inflammation as the possible cause of CA-125 rise. In addition, the elevated CA-125 levels were not due to MORAb-009 interfering with the laboratory assay used to measure CA-125. CONCLUSION: The increase in serum CA-125 produced by treatment with MORAb-009 is most likely due to MORAb-009 inhibiting the binding of tumor shed CA-125 to mesothelin present on mesothelial cells lining the pleural and peritoneal cavities. Inhibiting the mesothelin-CA-125 interaction could be a useful strategy to prevent tumor metastasis in mesotheliomas and ovarian cancer.

Farletuzumab, a humanized monoclonal antibody against folate receptor alpha, in epithelial ovarian cancer: a phase I study.

PURPOSE: Folate receptor α expression is highly restricted in normal adult tissues but upregulated in a wide range of human cancer types, including epithelial ovarian cancer. Farletuzumab, a humanized monoclonal antibody against folate receptor α, has shown antitumor activity and favorable toxicity in preclinical evaluation. This phase I, dose-escalation study was conducted to determine the safety of weekly i.v. farletuzumab and establish the maximum tolerated dose (MTD). EXPERIMENTAL DESIGN: Patients with platinum-refractory or platinum-resistant epithelial ovarian cancer received farletuzumab (12.5-400 mg/m(2)) on days 1, 8, 15, and 22 of a 5-week cycle. Intrapatient dose escalation was not permitted. Dose-limiting toxicity (DLT) was defined by treatment-related adverse event of grade 3 or higher, and the MTD was the highest dose at which one or none of six patients experienced a DLT. Disease progression was recorded using Response Evaluation Criteria in Solid Tumors criteria and serum CA-125. RESULTS: Twenty-five heavily pretreated patients were included in the safety, efficacy, and pharmacokinetic analyses. No DLTs or MTDs were encountered, and dose escalation was continued to farletuzumab 400 mg/m(2). C(max) and AUC(0-24) (area under the serum concentration-time curve) increased in an approximately dose-proportional manner, and a nuclear imaging substudy confirmed tumor targeting. There were no objective responses. Stable disease by Response Evaluation Criteria in Solid Tumors was observed in nine (36%) patients and CA-125 reduction in four. Three patients received continued therapy and completed a total of up to three cycles. CONCLUSIONS: In this phase I study, farletuzumab administered as an i.v. infusion at doses of 12.5 to 400 mg/m(2) was generally safe and well tolerated in the management of heavily pretreated patients with epithelial ovarian cancer.