In Vitro and In Vivo Activity of AMG 337, a Potent and Selective MET Kinase Inhibitor, in MET-Dependent Cancer Models

The MET receptor tyrosine kinase is involved in cell growth, survival, and invasion. Clinical studies with small molecule MET inhibitors have shown the role of biomarkers in identifying patients most likely to benefit from MET-targeted therapy. AMG 337 is an oral, small molecule, ATP-competitive, highly selective inhibitor of the MET receptor. Herein, we describe AMG 337 preclinical activity and mechanism of action in MET-dependent tumor models. These studies suggest MET is the only therapeutic target for AMG 337. In an unbiased tumor cell line proliferation screen (260 cell lines), a closely related analogue of AMG 337, Compound 5, exhibited activity in 2 of 260 cell lines; both were MET-amplified. Additional studies examining the effects of AMG 337 on the proliferation of a limited panel of cell lines with varying MET copy numbers revealed that high-level focal MET amplification (>12 copies) was required to confer MET oncogene addiction and AMG 337 sensitivity. One MET-amplified cell line, H1573 (>12 copies), was AMG 337 insensitive, possibly because of a downstream G12A KRAS mutation. Mechanism-of-action studies in sensitive MET-amplified cell lines demonstrated that AMG 337 inhibited MET and adaptor protein Gab-1 phosphorylation, subsequently blocking the downstream PI3K and MAPK pathways. AMG 337 exhibited potency in pharmacodynamic assays evaluating MET signaling in tumor xenograft models; >90% inhibition of Gab-1 phosphorylation was observed at 0.75 mg/kg. These findings describe the preclinical activity and mechanism of action of AMG 337 in MET-dependent tumor models and indicate its potential as a novel therapeutic for the treatment of MET-dependent tumors. Mol Cancer Ther; 15(7); 1568-79. ©2016 AACR.

A first-in-human study of AMG 208, an oral MET inhibitor, in adult patients with advanced solid tumors

BACKGROUND

This first-in-human study evaluated AMG 208, a small-molecule MET inhibitor, in patients with advanced solid tumors.

METHODS

Three to nine patients were enrolled into one of seven AMG 208 dose cohorts (25, 50, 100, 150, 200, 300, and 400 mg). Patients received AMG 208 orally on days 1 and days 4-28 once daily. The primary objectives were to evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of AMG 208.

RESULTS

Fifty-four patients were enrolled. Six dose-limiting toxicities were observed: grade 3 increased aspartate aminotransferase (200 mg), grade 3 thrombocytopenia (200 mg), grade 4 acute myocardial infarction (300 mg), grade 3 prolonged QT (300 mg), and two cases of grade 3 hypertension (400 mg). The MTD was not reached. The most frequent grade ≥3 treatment-related adverse event was anemia (n = 3) followed by hypertension, prolonged QT, and thrombocytopenia (two patients each). AMG 208 exposure increased linearly with dose; mean plasma half-life estimates were 21.4-68.7 hours. One complete response (prostate cancer) and three partial responses (two in prostate cancer, one in kidney cancer) were observed.

CONCLUSIONS

In this study, AMG 208 had manageable toxicities and showed evidence of antitumor activity, particularly in prostate cancer.

Clinical activity of AMG 337, an oral MET kinase inhibitor, in adult patients (pts) with MET-amplified gastroesophageal junction (GEJ), gastric (G), or esophageal (E) cancer

1

Background: Dysregulation of the MET pathway can promote tumor growth and metastasis. AMG 337 is an investigational, oral MET kinase inhibitor that is being evaluated in a first-in-human study. Here we describe the clinical activity, safety, and tolerability of AMG 337 in ptswith MET-amplified GEJ, G, and E cancers. Methods: Key eligibility criteria: age ≥ 18 years, advanced solid tumors, measurable disease, ECOG ≤ 2, adequate organ function. AMG 337 was administered QD or BID. Starting dose was 25 mg, with planned dose escalation of 50–500 mg QD and 100–200 mg BID. Ptswith MET overexpression/amplification/mutation could enroll to the highest dose deemed safe at any time. Results: As of April 2014, 80 pts had received ≥ 1 dose of AMG 337. Median (range) age, 58 (19–79) years; men, 61%; ECOG ≤ 1, 96%. Of the 51 pts with pre- and post-central read data, 10 pts had MET-amplified GI cancers (all of which were GEJ, G, or E cancers). Responses in these pts are shown in the table. One pt had a complete response (duration 100 wks) and 4 pts had partial responses (durations up to 52 wks). The most common treatment-emergent AEs (in > 20% of all pts) were headache, nausea, fatigue, vomiting, and constipation. AEs and dose-limiting toxicities were reported previously (Hong et al., ASCO 2014). The AE profile of pts with GI cancers was comparable to that of all ptsenrolled in the study. QD maximum tolerated dose (MTD) is 300 mg; BID MTD has not been reached. Conclusions: Responses to AMG 337 were observed in a subset of pts with MET-amplified GI tumors. A dose-expansion phase will enroll up to 50 ptswith MET-amplified tumors at the MTD. Clinical trial information: NCT01253707. [Table: see text]

First-in-human study of AMG 208, an oral MET inhibitor, in adult patients (pts) with advanced solid tumors

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Background: AMG 208 is a small molecule MET inhibitor that suppresses proliferation and induces apoptosis in human tumor xenografts. This first-in-human study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of AMG 208. We report data from the dose escalation part of the study. Methods: Key eligibility criteria: ≥ 18 yr, advanced solid tumors, ECOG ≤ 2, and evaluable/measurable disease. Using a modified Fibonacci design, 3–9 pts were enrolled into 1 of 7 sequential dose cohorts (25, 50, 100, 150, 200, 300, and 400 mg) of AMG 208. Pts received AMG 208 orally on days 1 and 4–28 once daily. If no dose limiting toxicity (DLT) was seen on days 1–28, pts received AMG 208 once daily starting at day 36 provided pts showed no evident disease progression. In cohorts 1–3, a standard 3+3 design was followed. In cohorts 4–7, a modified 3+3+3 design was followed. Results: As of July 16 2012, 54 pts (25 mg [n=6], 50 mg [n=4], 100 mg [n=4], 150 mg [n=3], 200 mg [n=16], 300 mg [n=10], and 400 mg [n =11]) had received ≥ 1 dose of AMG 208. 67% were men; 19% had prostate cancer (PC). Median (range) age: 61 (39–80) yr. ECOG 0/1: 52%/48%. 6 DLTs were seen: a grade (G) 3 increased AST (200 mg), a G3 thrombocytopenia (200 mg), a G4 acute myocardial infarction (300 mg), a G3 prolonged QT (300 mg), and two G3 hypertensions (400 mg). The maximum tolerated dose was not reached. 83% of pts had tx-related adverse events (AE). Tx-related AE occurring in > 10 pts: fatigue (n=24), nausea (n=18), hypertension (n=12), and diarrhea (n=11). 24% of pts had grade ≥ 3 tx-related AE. AMG 208 was orally bioavailable with a 30–35 hr mean half-life in plasma. Exposure increased linearly with dose; accumulation at day 28 was 2.7-fold across cohorts. Of the 42 pts with available tumor response data for site reads, 1 had complete response on bone scan (PC 300 mg) while 2 had partial responses (PR; PC 400 mg and kidney cancer 200 mg; both had -33% tumor shrinkage), and 29 had stable disease (SD); 1 other PC pt had PR after data cutoff. Of the 35 pts with available tumor response data for central reads, 26 had SD. FLT and biomarker data will be presented. Conclusions: AMG 208 up to 400 mg daily had manageable toxicities and showed evidence of antitumor activity, especially in prostate cancer. Clinical trial information: NCT00813384.

The Thread of Life

I had a great-grandmother who lived two doors away from us. She and I were constantly together. But one thing I do remember is when we left Italy. A few days before, she and I took a walk to her land and she was very, very sad. She said, “Ah.” She said, “you're going to America now. Someday you will remember me.” But, “she said, “remember when you get there, when you reach the Battery there is a row of fountains there. You have, to see that there is one, find out which one it is, that you cannot drink out of. Because when you drink from that certain fountain you're going to forget all of us that you're leaving here.” So when I arrived at the Battery I was looking for the row of fountains, but I didn't see the row of fountains. So I said I guess since I didn't see them it must be okay. She also wanted me to write and tell her about the Brooklyn Bridge, because she had heard about the Brooklyn Bridge. But she died before I saw the Brooklyn Bridge. Today, when I'm driving along, many, many times I think of her. The words echo in my memory. “You're going to America now. Some day you will remember me.”

[Unresectable hilar cholangiocarcinoma: combined percutaneous and radiotherapic treatment]

PURPOSE

Evaluate, in patients with inoperable hilar CLCA, the efficacy of multimodality treatment (brachiotherapy, chemotherapy, external radiotherapy and endoprosthesis positioning) in terms of survival, quality of life and cost/benefit compared to palliative surgical treatment.

MATERIAL AND METHODS

20 patients with inoperable hilar CLCA were evaluated. Ten were considered for combined palliative and radiotherapy treatment according to the following protocol: percutaneous colangiography followed by positioning of right and left internal biliar drainage (10-12 F); intraductal brachiotherapy using Ir-192 needles was performed (7 Gy). A second administration was after 7 days. Total dose was 14 Gy; the biliar drainages were then replaced by endoprosthesis (12-14 F) and left in position for 3 months in order to model the post-attinic fibrosis and to prevent stenosis; external radiotherapy was administered starting 15 days after last brachiotherapy treatment (26 administrations (180 cGy) in 5 weeks, total 46 Gy); chemotherapy (5 FU: 350 mg/mq/die) for 5 days during the first and the fifth week of external radiotherapy; biliar endoprosthesis were removed by endoscopic and, or transhepatic mode after 3 months from end of therapy, verifying. Cholangiography assessed the patency of the biliar duct. Metallic stents were placed if results were not satisfactory; follow-up was by: hepatic lab work-up, tumoral markers, US or TC evaluated disease progression.

RESULTS

In 5 of the 10 patients considered for the combined treatment, 5 patients completed the protocol and 5 were treated only with brachiotherapy because of deterioration of clinical conditions. All patients had initial complete remission of jaundice although it recurred with disease progression that led to death. No acute post-radiotherapy complication was observed. Digestive hemorrhage (chronic post-radiotherapy complication) was the cause of death in one patient.

DISCUSSION AND CONCLUSIONS

Good results were observed in the patients that completed the protocol, mean survival was 7,5 months instead of 1,75 months as in patients that underwent only percutaneous drainage. Better results may be obtained taking in consideration the poor clinical conditions of the patients at the time of diagnosis. The proposed therapeutic protocol requires an average hospitalization of 10-15 days instead of 15-20 days as for palliative biliar-digestive deviation, being less invasive and thus associated to lower morbidity and no mortality.

[The percutaneous treatment of uterine fibromas by means of transcatheter arterial embolization]

INTRODUCTION

We report our preliminary experience with arterial embolization of uterine fibroids in seven women, focusing on the technical aspects of the procedure and the clinical and morphological results during the follow-up.

MATERIAL AND METHODS

February to December 1999 seven women (mean age 47) underwent transcatheter arterial embolization of both uterine arteries as a permanent treatment for fibroids. We included in this study single or multiple, bleeding and/or large fibroids, symptomatic on compression, contraindicated for myomectomy because of high surgical or anesthesiologic risks or myomata in which myomectomy could probably be converted into hysterectomy. Fibroids enlarging the uterus to the size of 25 weeks' pregnancy or more, pedunculated myomata or small submucous fibroids--smaller than 5 cm--were excluded. Uterine arterial embolization was performed bilaterally, till a total blockage of flow, by injecting permanent embolization material: polyvinyl-alcohol (PVA) particles of increasing size from 150 to 500 mu and in varying amounts from 10 to 24 mL, depending on fibroid size and degree of vascularization.

RESULTS

A technical success was achieved in all cases and no late complications were seen. At 6-month clinical follow-up all compressive symptoms had disappeared; regular menses had returned in 57% of patients, milder hyper-dysmenorrhea was present in 28% compared to pretreatment symptoms; only in one case (14%) was permanent amenorrhea observed. The 3-month and 6-month US follow-up studies showed an average 40.7% (range 10-50%) and 51% (range 25-83%) reduction in the fibroid size, respectively. All the small myomata (about 2 cm in size) were unidentifiable at 6-month US follow-up. In no cases did new fibroids appear.

DISCUSSION

Surgery is the traditional treatment for symptomatic uterine fibroids (hysterectomy, myomectomy). More recently, hormone therapy and operative endoscopy (laparoscopy and hysteroscopy) have been introduced as alternatives, together with uterine embolization previously applied preoperatively in extensive bleeding neoplasms or to control post-partum hemorrhage. Transcatheter embolization of the uterine arteries feeding large fibroids is a minimally invasive technique which could be safely used as an alternative to surgery, and a valuable in the definitive treatment of symptomatic, large or multiple, intramural or submucosal fibroids. In agreement with literature findings, in the present series symptoms resolved completely in over 85% of cases after embolization, with an average reduction in fibroid size over 50% at 6-month follow-up in large fibroids, whereas smaller size myomata were no longer detectable at US and no new fibroids had formed.

CONCLUSIONS

Our preliminary experience confirms that arterial embolization is a promising alternative to surgery in the definitive treatment of fibroids, thanks to its high efficacy and safety, also reducing patient hospitalization and costs.

Prolonged inhibition of nitric oxide synthesis in Yoshida hyperlipidemic rat: aorta functional and structural properties

To test whether inhibition of nitric oxide synthesis, associated with high levels of plasmatic lipids, can induce atherosclerotic lesions and phenotypic changes in smooth muscle cell composition in the aortic wall of an atherosclerotic-resistant species such as the rat, an inbred strain of hyperlipidemic Pittsburgh Yoshida rat was subjected to prolonged treatment (2 months) with the nitric oxide-synthase inhibitor L omega-nitro-arginine-methyl ester or with L-arginine. The two types of in vivo treatments were not able to modify in vitro aortic endothelium-mediated relaxation induced by acetylcholine or calcium-ionophore A-23187, the endothelium-independent sodium nitrite relaxation and the contractile response to serotonin. Histology and lipid infiltration of vascular specimens showed that L omega-nitro-arginine-methyl ester in vivo treatment did not induce any significant change in the aortic wall. Monoclonal antibodies to myosin isoforms and immunofluorescence procedures revealed the presence of an immature smooth muscle cell subpopulation in aortic specimens from saline-treated Pittsburgh Yoshida rats, whose expansion has been related in other species to atherogenesis. This peculiar cell phenotype disappeared in our animal model after prolonged L omega-nitro-arginine-methyl ester treatment. These data indicate that, despite interference with endothelium-mediated nitric oxide synthesis, atherosclerosis does not develop in this animal model and furnish for the first time a biological justification for atherogenesis resistance of rat, i.e., the lack of activation of an immature aortic smooth muscle cell population which in atherosclerosis-prone species is involved in lesion formation.

Atherosclerosis resistance in rats correlates with lack of expansion of an immature smooth muscle cell population

In this study we asked whether the well-known atherosclerosis resistance of rats might be reduced with aging. Two groups of young, adult and aged Wistar rats, one of which was kept on a standard, low-cholesterol (CT) diet, and the other one was fed a 2% CT diet for 2 months were enrolled. Potential modifications in the phenotypic profile of aortic smooth muscle (SM) were assessed by SDS-gel electrophoresis, Western blotting and immunofluorescence procedures using a panel of monoclonal antibodies to myosin isoforms, cytoskeletal and extracellular matrix proteins. With development and aging, the expression of 196-kD non-muscle-type myosin heavy-chain isoform (MyHC), the EIIIA fibronectin variant and keratins was downregulated, whereas that of the 204- and 200-kD SM-type MyHC isoforms, SM-type alpha-actin and desmin did not change. The levels of hypercholesterolemia achieved in this model did not substantially modify the distribution of the downregulated markers, except for the subendothelial grouping of immature SM cells in aged rats. Morphometric measurements indicated a slight increase of medial cross-sectional area accompanied by a decrease in total SM cell number, both with aging and with hypercholesterolemia. In no circumstance was the presence of atherosclerotic lesions histologically detectable. Bromo-deoxyuridine (BrdU) incorporation analysis revealed a marked age-dependent decline in DNA synthesis and the formation of binucleated cells in aged aortas. This pattern was not influenced by hypercholesterolemia, except in aged rats where BrdU-positive SM cells are almost doubled. Our data indicate that aging and hypercholesterolemia cannot affect the phenotypic stability of rat SM cells and confirm that the change from a fully differentiated to an immature state is a general prerequisite to allow the development of atherosclerotic lesions in mammalian species.

Mechanism of adenosine receptor-induced renal vasoconstriction in rats

Adenosine analogues selective for the A1 subclass of adenosine receptors, such as N6-cyclohexyladenosine (CHA), induce vasoconstriction in the isolated rat kidney perfused at constant flow. Presumably, the vasoconstriction is mediated by increased Ca2+ concentration in renal vascular smooth muscle cells, but the mechanism by which A1 adenosine receptor occupation leads to increased Ca2+ is unknown. In the present experiments, the isolated, perfused rat kidney vasoconstricted in response to CHA, to K depolarization, and to BAY K 8644 (a Ca2+ channel agonist). All of these responses were completely blocked by methoxyverapamil, which suggests that CHA, like K depolarization and BAY K 8644, induces renal vasoconstriction by increasing Ca2+ influx through potential operated Ca2+ channels. The mechanism of action of CHA was different, however, in that pertussis toxin treatment blocked the response to CHA without affecting the responses to K depolarization or to BAY K 8644. Therefore, a pertussis toxin-sensitive step must intervene between occupation of A1 adenosine receptors on renal vascular smooth muscle cells and increased Ca2+ influx through potential-operated Ca2+ channels.