Andecaliximab/GS-5745 Alone and Combined with mFOLFOX6 in Advanced Gastric and Gastroesophageal Junction Adenocarcinoma: Results from a Phase I Study.

Purpose: Matrix metalloproteinase-9 (MMP9) is implicated in protumorigenic processes. Andecaliximab (GS-5745, a monoclonal antibody targeting MMP9) was evaluated as monotherapy and in combination with mFOLFOX6.Patients and Methods: Three dosages of andecaliximab monotherapy [200, 600, and 1800 mg i.v. every 2 weeks (q2w)] were investigated in patients with advanced solid tumors (n = 13 in a 3+3 design). After determining a recommended dose, patients with advanced HER2-negative gastric/gastroesophageal junction (GEJ) adenocarcinoma (n = 40) received 800 mg andecaliximab + mFOLFOX6 q2w. Pharmacokinetics, pharmacodynamics, safety, and efficacy were assessed.Results: Andecaliximab monotherapy demonstrated no dose-limiting toxicity (DLT) in any cohort, displaying target-mediated drug disposition at the lowest dose (200 mg) and linear pharmacokinetics at higher doses. Based on target engagement, recommended doses for further study are 800 mg q2w or 1,200 mg q3w. Maximal andecaliximab target binding, defined as undetectable andecaliximab-free MMP9 in plasma, was observed in the gastric/GEJ adenocarcinoma cohort. We observed no unusual toxicity, although there were four deaths on study not attributed to andecaliximab treatment. In first-line patients (n = 36), median progression-free survival (PFS) was 9.9 months [95% confidence interval (CI), 5-13.9 months], and the overall response rate (ORR) was 50%. Among all patients (n = 40), median PFS was 7.8 (90% CI, 5.5-13.9) months, and ORR was 48%, with a median duration of response of 8.4 months.Conclusions: Andecaliximab monotherapy achieved target engagement without DLT. Andecaliximab + mFOLFOX6 showed encouraging clinical activity without additional toxicity in patients with HER2-negative gastric/GEJ adenocarcinoma. A phase III study evaluating mFOLFOX6 ± andecaliximab in this setting is ongoing. Clin Cancer Res; 24(16); 3829-37. ©2018 AACR.

Momelotinib versus best available therapy in patients with myelofibrosis previously treated with ruxolitinib (SIMPLIFY 2): a randomised, open-label, phase 3 trial.

BACKGROUND: The Janus kinase (JAK) inhibitor ruxolitinib is the only approved therapy for patients with symptomatic myelofibrosis. After ruxolitinib failure, however, there are few therapeutic options. We assessed the efficacy and safety of momelotinib, a JAK 1 and JAK 2 inhibitor, versus best available therapy (BAT) in patients with myelofibrosis who had suboptimal responses or haematological toxic effects with ruxolitinib. METHODS: In this randomised, phase 3, open-label trial, patients were screened for eligibility from 52 clinical centres in Canada, France, Germany, Israel, Italy, Spain, the UK, and the USA. Patients who had myelofibrosis and previous ruxolitinib treatment for at least 28 days who either required red blood cell transfusions while on ruxolitinib or ruxolitinib dose reduction to less than 20 mg twice a day with at least one of grade 3 thrombocytopenia, anaemia, or bleeding at grade 3 or worse, with palpable spleen of at least 5 cm and without grade 2 or greater peripheral neuropathy were included in the study. Patients were randomly assigned (2:1) to either 24 weeks of open-label momelotinib 200 mg once a day or BAT (which could include ruxolitinib, chemotherapy, steroids, no treatment, or other standard interventions), after which all patients could receive extended momelotinib treatment. Patients were randomly assigned to treatment by an interactive web response system and the randomisation was stratified by transfusion dependence and by baseline total symptom score (TSS). Results were analysed on an intention-to-treat basis. The primary endpoint was a reduction by at least 35% in the spleen volume at 24 weeks compared with baseline. Safety analyses included adverse event monitoring. The trial is registered with ClinicalTrials.gov, number NCT02101268. FINDINGS: Between June 19, 2014, and July 28, 2016, 156 patients were recruited to the study; 104 received momelotinib and 52 received BAT. BAT was ruxolitinib in 46 (89%) of 52 patients. 73 (70%) of 104 patients in the momelotinib group and 40 (77%) of 52 patients in the BAT group completed the 24-week treatment phase. Seven (7%) of 104 patients in the momelotinib group and three (6%) of 52 in the BAT group had a reduction in the spleen volume by at least 35% compared with baseline (proportion difference [Cochran-Mantel-Haenszel method], 0·01; 95% CI -0·09 to 0·10), p=0·90). The most common grade 3 or worse adverse events were anaemia (14 [14%] of 104 in the momelotinib group vs seven [14%] of 52 in the BAT group), thrombocytopenia (seven [7%] vs three [6%]), and abdominal pain (one [1%] vs three [6%]). Peripheral neuropathy occurred in 11 (11%) of 104 patients receiving momelotinib (one of which was grade 3) and in no patients in the BAT group. Serious events were reported for 36 (35%) patients in the momelotinib group and 12 (23%) of patients in the BAT group. Deaths due to adverse events were reported for six patients (6%) receiving momelotinib (acute myeloid leukaemia [n=2], respiratory failure [n=2, with one considered possibly related to momelotinib], cardiac arrest [n=1, considered possibly related to momelotinib], and bacterial sepsis [n=1]); and four patients (8%) receiving BAT (lung adenocarcinoma [n=1], myelofibrosis [n=1], and sepsis [n=2]). INTERPRETATION: In patients with myelofibrosis previously treated with ruxolitinib, momelotinib was not superior to BAT for the reduction of spleen size by at least 35% compared with baseline. FUNDING: Gilead Sciences, Inc.

SIMPLIFY-1: A Phase III Randomized Trial of Momelotinib Versus Ruxolitinib in Janus Kinase Inhibitor-Naïve Patients With Myelofibrosis.

Purpose We evaluated the efficacy and safety of momelotinib, a potent and selective Janus kinase 1 and 2 inhibitor (JAKi), compared with ruxolitinib, in JAKi-naïve patients with myelofibrosis. Patients and Methods Patients (N = 432) with high risk or intermediate-2 risk or symptomatic intermediate-1 risk myelofibrosis were randomly assigned to receive 24 weeks of treatment with momelotinib 200 mg once daily or ruxolitinib 20 mg twice a day (or per label), after which all patients could receive open-label momelotinib. The primary end point was a ≥ 35% reduction in spleen volume at 24 weeks of therapy. Secondary end points were rates of symptom response and effects on RBC transfusion requirements. Results A ≥ 35% reduction in spleen volume at week 24 was achieved by a similar proportion of patients in both treatment arms: 26.5% of the momelotinib group and 29% of the ruxolitinib group (noninferior; P = .011). A ≥ 50% reduction in the total symptom score was observed in 28.4% and 42.2% of patients who received momelotinib and ruxolitinib, respectively, indicating that noninferiority was not met ( P = .98). Transfusion rate, transfusion independence, and transfusion dependence were improved with momelotinib (all with nominal P ≤ .019). The most common grade ≥ 3 hematologic abnormalities in either group were thrombocytopenia and anemia. Grade ≥ 3 infections occurred in 7% of patients who received momelotinib and 3% of patients who received ruxolitinib. Treatment-emergent peripheral neuropathy occurred in 10% of patients who received momelotinib (all grade ≤ 2) and 5% of patients who received ruxolitinib (all grade ≤ 3). Conclusion In JAKi-naïve patients with myelofibrosis, 24 weeks of momelotinib treatment was noninferior to ruxolitinib for spleen response but not for symptom response. Momelotinib treatment was associated with a reduced transfusion requirement.

A phase 2 study of momelotinib, a potent JAK1 and JAK2 inhibitor, in patients with polycythemia vera or essential thrombocythemia.

Momelotinib is a potent inhibitor of JAK1 and JAK2 that demonstrated efficacy in patients with primary and secondary myelofibrosis. This phase 2, open-label, randomized study evaluated the efficacy and safety of oral once-daily momelotinib (100mg and 200mg) for the treatment of polycythemia vera (PV) and essential thrombocythemia (ET). The primary endpoint for PV was overall response rate (ORR), defined as the proportion of patients with hematocrit <45%, white blood cell count <10×109/L, platelet count ≤400×109/L, and resolution of palpable splenomegaly, each lasting ≥4 weeks. The definition of ORR for ET excluded the hematocrit component. A total of 39 patients (28 PV, 11 ET) were enrolled, with 28 patients receiving ≥12 weeks of treatment. The study was terminated due to limited efficacy. Two patients (ORR 5.1%) met the primary efficacy endpoint (both PV 200mg). Predose plasma levels of momelotinib were stable over time. A total of 31 (79.5%) patients experienced momelotinib-related adverse events (AEs), the most frequent being headache (23.1%), dizziness (18.0%), somnolence (15.4%), nausea (15.4%), and fatigue (15.4%). Three patients experienced serious AEs (7.7%), with 1 considered related to momelotinib (dyspnea). Peripheral neuropathy occurred in 7 (17.9%) patients (4 PV, 3 ET).

A phase 2 study of simtuzumab in patients with primary, post-polycythaemia vera or post-essential thrombocythaemia myelofibrosis.

Simtuzumab, a monoclonal antibody inhibitor of extracellular matrix enzyme lysyl oxidase-like-2, showed preclinical promise and was well tolerated in clinical studies. A phase 2, open-label study of simtuzumab was conducted in patients with primary myelofibrosis (MF), post-polycythaemia vera MF and post-essential thrombocythaemia MF. Fifty-four patients were randomized to receive simtuzumab alone (200 or 700 mg [n = 12 each group]) or simtuzumab (200 or 700 mg) with ruxolitinib (n = 15 each group) for 24 weeks. Simtuzumab alone or in combination with ruxolitinib showed no clinical benefit at 24 weeks. The mean serum simtuzumab trough concentrations appeared to increase dose-proportionally between the 200-mg and 700-mg treatment groups. Therapy-related serious adverse events were pyrexia, pain in extremity (both in 1 patient) and infusion reaction (in another patient). Bone marrow fibrosis (BMF) score was reduced at 24 weeks in 2 patients (16·7%) in the simtuzumab 700-mg group, 1 (6·7%) in the simtuzumab 200-mg + ruxolitinib group, and 2 (13·3%) in the simtuzumab 700-mg + ruxolitinib group; similar numbers of patients had increased BMF. Simtuzumab alone or with ruxolitinib was well tolerated but did not produce clinical benefit nor consistently reduce BMF in patients with MF by 24 weeks.

Population pharmacokinetics and exposure-response relationship of amatuximab, an anti-mesothelin monoclonal antibody, in patients with malignant pleural mesothelioma and its application in dose selection.

PURPOSE: To characterize amatuximab pharmacokinetics (PK) and the relationship of amatuximab exposure with response in patients with unresectable malignant pleural mesothelioma (MPM) receiving amatuximab with pemetrexed and cisplatin. METHODS: A nonlinear mixed effects PK model was built using data from all of the amatuximab studies conducted to date. Patients received amatuximab alone or in combination with chemotherapy. The influence of demographic, laboratory and disease characteristics on PK parameters was assessed. Exposure-response analyses explored relationships between amatuximab exposure and overall survival (OS), progression-free survival (PFS) and safety. Alternative amatuximab dosing regimens were explored with simulations using population PK and parametric survival models. RESULTS: Amatuximab PK was best described by a two-compartment model with parallel linear and nonlinear elimination pathways. Body weight and an antidrug antibodies reaction with the titer >64 affected volume of distribution and clearance, respectively. Exposure-response analyses demonstrated that the amatuximab exposure (C min) showed a significant effect on OS (log-rank test, P = 0.0202). For patients with amatuximab C min above the median (38.2 µg/mL), the median OS was 583 days (90 % CI 418 -NE). For patients with C min ≤ 38.2 µg/mL, the median OS was 375 days (90 % CI 325-486). The amatuximab exposure showed similar significant effect on PFS. Exposure-response analysis for adverse events did not reveal any relationship. CONCLUSIONS: In patients with MPM, higher amatuximab exposure in combination with chemotherapy was shown to be associated with longer OS, supporting evaluation of more frequent dosing in future trials to achieve higher exposure and subsequently longer OS.

Folate receptor-α (FOLR1) expression and function in triple negative tumors.

Folate receptor alpha (FOLR1) has been identified as a potential prognostic and therapeutic target in a number of cancers. A correlation has been shown between intense overexpression of FOLR1 in breast tumors and poor prognosis, yet there is limited examination of the distribution of FOLR1 across clinically relevant breast cancer subtypes. To explore this further, we used RNA-seq data from multiple patient cohorts to analyze the distribution of FOLR1 mRNA across breast cancer subtypes comprised of estrogen receptor positive (ER+), human epidermal growth factor receptor positive (HER2+), and triple negative (TNBC) tumors. FOLR1 expression varied within breast tumor subtypes; triple negative/basal tumors were significantly associated with increased expression of FOLR1 mRNA, compared to ER+ and HER2+ tumors. However, subsets of high level FOLR1 expressing tumors were observed in all clinical subtypes. These observations were supported by immunohistochemical analysis of tissue microarrays, with the largest number of 3+ positive tumors and highest H-scores of any subtype represented by triple negatives, and lowest by ER+ tumors. FOLR1 expression did not correlate to common clinicopathological parameters such as tumor stage and nodal status. To delineate the importance of FOLR1 overexpression in triple negative cancers, RNA-interference was used to deplete FOLR1 in overexpressing triple negative cell breast lines. Loss of FOLR1 resulted in growth inhibition, whereas FOLR1 overexpression promoted folate uptake and growth advantage in low folate conditions. Taken together, our data suggests patients with triple negative cancers expressing high FOLR1 expression represent an important population of patients that may benefit from targeted anti-FOLR1 therapy. This may prove particularly helpful for a large number of patients who would typically be classified as triple negative and who to this point have been left without any targeted treatment options.

Phase II clinical trial of amatuximab, a chimeric antimesothelin antibody with pemetrexed and cisplatin in advanced unresectable pleural mesothelioma.

PURPOSE: Amatuximab is a chimeric monoclonal antibody to mesothelin, a cell surface glycoprotein highly expressed in malignant pleural mesothelioma (MPM). On the basis of its synergy with chemotherapy in preclinical studies, we evaluated the antitumor activity of amatuximab plus pemetrexed and cisplatin in patients with unresectable MPM. EXPERIMENTAL DESIGN: In a single-arm phase II study, amatuximab (5 mg/kg) was administered on days 1 and 8 with pemetrexed (500 mg/m(2)) and cisplatin (75 mg/m(2)) on day 1 of 21-day cycles for up to six cycles. Patients with response or stable disease received amatuximab maintenance until disease progression. Primary endpoint was progression-free survival (PFS) at 6 months. Secondary endpoints were overall survival (OS), response rate, and safety. RESULTS: Eighty-nine patients were enrolled at 26 centers. Median of five cycles (range, 1-6) of combination treatment was administered, and 56 (63%) patients received amatuximab maintenance. Combination therapy resulted in no overlapping toxicities. Eleven patients (12.4%) had amatuximab-related hypersensitivity reactions. Responses included partial responses in 33 (40%) and stable disease in 42 (51%). Six-month PFS rate was 51% [95% confidence interval (CI), 39.1-62.3)], median PFS was 6.1 months (95% CI, 5.8-6.4), and median OS was 14.8 months (95% CI, 12.4-18.5) with 29 patients alive at data cut-off. CONCLUSIONS: Amatuximab with pemetrexed and cisplatin was well tolerated with objective tumor response or stable disease rate of 90% by independent radiologic review. Although PFS was not significantly different from historical controls, the median OS was 14.8 months with a third of patients alive and 5 continuing to receive amatuximab at the time of analysis.

Assessment of folate receptor-α and epidermal growth factor receptor expression in pemetrexed-treated non-small-cell lung cancer patients.

INTRODUCTION: Folate receptor-α regulates cellular uptake of folates and antifolates (eg, pemetrexed) and is frequently expressed in pulmonary adenocarcinoma. EGFR is an established therapeutic target in NSCLC. Therapies targeting FRA or EGFR are available. The association between FRA and EGFR expression in advanced NSCLC has not been explored. Combining therapeutic FRA antibodies with an EGFR inhibitor might be beneficial, if both of the targets are significantly coexpressed. PATIENTS AND METHODS: Specimens from 160 advanced NSCLC patients receiving pemetrexed-based chemotherapy were assessed for membranous FRA and EGFR protein expression using immunohistochemistry and the Hybrid (H)-score. EGFR (exons 18-21) and Kirsten RNA-associated rat sarcoma 2 virus (exon 2) mutations were determined. Results were correlated to patients' clinicopathological data, progression-free survival (PFS), and overall survival (OS). RESULTS: Forty-seven patients (29%) had tumors with strong FRA and EGFR expression, but no statistically significant correlation was seen between protein levels of FRA and EGFR. High membranous FRA expression (H-score ≥ 20) was associated with prolonged PFS (5.5 vs. 3.4 months; hazard ratio [HR], 0.6060; P = .0254) and improved OS (12.1 vs. 6.4 months; HR, 0.5726; P = .0076). CONCLUSION: Survival times are improved in NSCLC patients whose tumors show strong membranous FRA expression. No statistical correlation between membranous FRA and EGFR expression was demonstrated in advanced NSCLC, but 47 patients (29%) had higher expression of both of the receptors and could be suitable for combined targeted therapies.

Significance of folate receptor alpha and thymidylate synthase protein expression in patients with non-small-cell lung cancer treated with pemetrexed.

INTRODUCTION: Folate receptor alpha (FRA) regulates cellular uptake of folates and antifolates. Information about FRA protein expression in metastatic non-small-cell lung cancer (NSCLC) is limited. We investigated FRA as a biomarker for pemetrexed-based chemotherapy and compared it with thymidylate synthase (TS), the main target of pemetrexed. METHODS: Pretreatment tumor specimens from 207 patients with advanced NSCLC were assessed for FRA and TS protein expression by immunohistochemistry using the H-score (range, 0-300) and correlated to patients' clinicopathological data, radiographic response, progression-free survival (PFS), and overall survival (OS). RESULTS: Low total (cytoplasmic and nuclear) TS protein expression (H-score < 210) was associated with improved PFS (median: 5.6 versus 3.5 months; hazard ratio [HR] = 0.6379, p = 0.0131) and prolonged OS (median: 22.5 versus 11.5 months; HR = 0.5680,p = 0.0107). An association between lower TS levels and response to pemetrexed-based therapy was found-mean H-score 187 ± 5, median 180 for responders versus mean H-score 201 ± 4, median 210, for non-responders, p = 0.0244. High intracellular FRA expression (H-score ≥110) was associated with prolonged OS (28.9 versus 11.7 months, HR = 0.5316, p = 0.0040) and a trend for association with PFS (5.6 versus 4.1 months, HR = 0.7395, p = 0.0801) was noted. Membranous FRA expression was seen in 83% of patients, moreover, high membranous expression (H-score ≥20) was associated with improved PFS (5.6 versus 3.7 months, HR = 0.6445, p = 0.0306) and OS (22.1 versus 11.5 months, HR = 0.5378, p = 0.0131). CONCLUSIONS: A large number of NSCLC patients have high expression of FRA and/or a low level of TS expression. Expression levels of FRA and TS were associated with clinical benefit from pemetrexed therapy.