A randomized, open-label study of the efficacy and safety of AZD4547 monotherapy versus paclitaxel for the treatment of advanced gastric adenocarcinoma with FGFR2 polysomy or gene amplification.

BACKGROUND: Approximately 5%-10% of gastric cancers have a fibroblast growth factor receptor-2 (FGFR2) gene amplification. AZD4547 is a selective FGFR-1, 2, 3 tyrosine kinase inhibitor with potent preclinical activity in FGFR2 amplified gastric adenocarcinoma SNU16 and SGC083 xenograft models. The randomized phase II SHINE study (NCT01457846) investigated whether AZD4547 improves clinical outcome versus paclitaxel as second-line treatment in patients with advanced gastric adenocarcinoma displaying FGFR2 polysomy or gene amplification detected by fluorescence in situ hybridization. PATIENTS AND METHODS: Patients were randomized 3:2 (FGFR2 gene amplification) or 1:1 (FGFR2 polysomy) to AZD4547 or paclitaxel. Patients received AZD4547 80 mg twice daily, orally, on a 2 weeks on/1 week off schedule of a 21-day cycle or intravenous paclitaxel 80 mg/m2 administered weekly on days 1, 8, and 15 of a 28-day cycle. The primary end point was progression-free survival (PFS). Safety outcomes were assessed and an exploratory biomarker analysis was undertaken. RESULTS: Of 71 patients randomized (AZD4547 n = 41, paclitaxel n = 30), 67 received study treatment (AZD4547 n = 40, paclitaxel n = 27). Among all randomized patients, median PFS was 1.8 months with AZD4547 and 3.5 months with paclitaxel (one-sided P = 0.9581); median follow-up duration for PFS was 1.77 and 2.12 months, respectively. The incidence of adverse events was similar in both treatment arms. Exploratory biomarker analyses revealed marked intratumor heterogeneity of FGFR2 amplification and poor concordance between amplification/polysomy and FGFR2 mRNA expression. CONCLUSIONS: AZD4547 did not significantly improve PFS versus paclitaxel in gastric cancer FGFR2 amplification/polysomy patients. Considerable intratumor heterogeneity for FGFR2 gene amplification and poor concordance between FGFR2 amplification/polysomy and FGFR2 expression indicates the need for alternative predictive biomarker testing. AZD4547 was generally well tolerated.

Clinical evaluation of AZD1152, an i.v. inhibitor of Aurora B kinase, in patients with solid malignant tumors.

BACKGROUND: To determine, for each of two dosing schedules, the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD) of AZD1152, an Aurora B kinase inhibitor, and to evaluate its safety, biologic activity and pharmacokinetics (PK). PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses (100-650 mg) of AZD1152, administered as a 2-h infusion every 7 days (A) or 14 days (B). Adverse events (AEs), PK variables and tumor response were assessed. RESULTS: Fifty-nine patients were treated; 19 in schedule A and 40 in schedule B. The MTDs were 200 and 450 mg, respectively. Neutropenia (with/without fever) was the most frequent AE and DLT in each schedule. Common Terminology Criteria of Adverse Events version 3.0 grade ≥3 neutropenia and leukopenia occurred in 58% and 11% of patients, respectively, in schedule A and 43% and 20%, respectively, in schedule B. No objective tumor responses were observed at any dose or schedule, although stable disease, as defined by RECIST, was achieved in 15 patients (25%) overall. Systemic exposure to AZD1152-hQPA (active drug) was observed by 1 h into the infusion and exhibited linear PK. CONCLUSIONS: AZD1152 was generally well tolerated with neutropenia being the most frequently reported AE and DLT. Exposure to AZD1152-hQPA, the active drug of AZD1152, was linear.

Antitumour activity and schedule dependency of 8-chloroadenosine-3',5'-monophosphate (8-ClcAMP) against human tumour xenografts.

8-Chloroadenosine-3',5'-monophosphate (8-ClcAMP) is a novel antitumour agent currently undergoing phase I clinical trials in several European centres. In this study, its antitumour activity against human tumour xenografts and its dependence on schedule were investigated. When administered by continuous infusion at doses of 100 or 50 mg/kg/day to nude mice bearing human tumour xenografts, 8-ClcAMP inhibited the growth of the HT 29 colorectal, ZR-75-1 breast, HOX 60 and PE04 ovarian and PANC-1 pancreatic carcinoma xenografts. However, these infusion schedules produced hypercalcaemia and severe weight loss. In an attempt to optimise antitumour activity and minimise toxicity, several other schedules were studied. In comparison with continuous administration of 8-ClcAMP at 50 mg/kg/day for 14 days which, although producing complete growth inhibition in the HOX 60 model, was associated with a marked body weight loss, schedules in which the infusion was interrupted (infusion on either days 0-4; 7-11 or days 0-2; 6-8) produced minimal weight loss but also reduced antitumour activity. However, co-administration of salmon calcitonin with continuous infusion of 8-ClcAMP prevented both hypercalcaemia and body weight loss in 3/6 animals while still producing marked inhibition of tumour growth. These data indicate that 8-ClcAMP has broad-spectrum antitumour activity and the major side-effect of hypercalcaemia may at least in part be ameliorated by the use of salmon calcitonin.

Characterization of the basic glutathione S-transferase B1 and B2 subunits from human liver.

The basic glutathione S-transferases in human liver are composed of at least two immunochemically distinct polypeptides, designated B1 and B2. These subunits exist as homodimers, but can hybridize to form the B1B2 heterodimer [Stockman, Beckett & Hayes (1985) Biochem. J. 227, 457-465]. Although these basic glutathione S-transferases possess similar catalytic properties, the B2 subunit exhibits significantly greater selenium-independent glutathione peroxidase activity than subunit B1. The use of the ligands haematin, tributyltin acetate and Bromosulphophthalein as inhibitors of 1-chloro-2,4-dinitrobenzene-GSH-conjugating activity clearly discriminate between the B1 and B2 subunits and should help facilitate their identification. Peptide mapping experiments showed that B1 and B2 are structurally distinct, but related, subunits; subunit B1 yielded 43 tryptic peptides, seven of which were unique, whereas subunit B2 yielded 40 tryptic peptides, four of which were unique.

Glutathione S-transferase subunits in the mouse and their catalytic activities towards reactive electrophiles.

The glutathione S-transferases (GST) are a major, multi-gene, group of detoxication proteins. A rapid, two-step purification, that employs S-hexylglutathione affinity chromatography and hydroxyapatite HPLC, is described for the GST isoenzymes in mouse liver. The major hepatic forms comprise Yf(Mr 24,500)-, Ya(Mr 26,000)- and Yb(Mr 27,000)-type subunits. The isoelectric points of the Yf, Ya and Yb dimers are 8.6, 9.2 and 7.8-8.2 respectively. Immunochemical experiments showed the purified mouse subunits cross-reacted with antisera raised against rat GST subunits that possessed equivalent molecular masses; the subunit sizes of the distinct subunit types are conserved between these two species. The catalytic activities of the purified mouse GST subunits are described. In common with other species the mouse GST are subject to tissue-specific expression. However, only mouse liver and not rat, guinea pig, hamster or human livers express the Yf polypeptide. The significance of this difference is unclear but, in the rat, the Yf subunit can serve as a marker for pre-neoplastic hepatocellular carcinogenesis.

Variations in the glutathione S-transferase subunits expressed in human livers.

Human livers express a variety of cytosolic glutathione S-transferase isoenzymes. The enzymes are subject to a marked polymorphism and the polypeptide basis of the differences in glutathione S-transferase content of individual livers has been investigated by Western blotting, hydroxyapatite HPLC and isoelectric focusing. Collectively, the livers examined contained three distinct groups of cytosolic glutathione S-transferase. The three classes of enzyme contain subunits of different molecular mass; subunits of 24.8 kDa (Yf), 26.0 kDa (Ya) and 26.7 kDa (Yb) were found to belong to the 'acidic-type', 'basic-type' and 'neutral-type' glutathione S-transferase, respectively. All livers studied contained 26.0 kDa subunits (Ya or 'basic') but significant differences in the isoelectric points of this group of proteins were demonstrated. Five of the eight livers examined expressed 26.7 kDa subunits (Yb or 'neutral'); the native enzymes had pI values of either 6.1 or 5.5, and were isolated by hydroxyapatite HPLC. Two of the livers possessed 24.8 kDa subunits (Yf or 'acidic'), and the native enzyme, which had a pI of 4.8, was also purified by hydroxyapatite HPLC. Before undertaking a glutathione S-transferase purification it is advisable to determine the GST isoenzyme content of a number of livers. The suitability of the methods described in the present study for use as screening procedures is discussed.

Identification of a basic hybrid glutathione S-transferase from human liver. Glutathione S-transferase delta is composed of two distinct subunits (B1 and B2).

The purification of a hybrid glutathione S-transferase (B1 B2) from human liver is described. This enzyme has an isoelectric point of 8.75 and the B1 and B2 subunits are distinguishable immunologically and are ionically distinct. Hybridization experiments demonstrated that B1 B1 and B2 B2 could be resolved by CM-cellulose chromatography and have pI values of 8.9 and 8.4 respectively. Transferase B1 B2, and the two homodimers from which it is formed, are electrophoretically and immunochemically distinct from the neutral enzyme (transferase mu) and two acidic enzymes (transferases rho and lambda). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that B1 and B2 both have an Mr of 26 000, whereas, in contrast, transferase mu comprises subunits of Mr 27 000 and transferases rho and lambda both comprise subunits of Mr 24 500. Antisera raised against B1 or B2 monomers did not cross-react with the neutral or acidic glutathione S-transferases. The identity of transferase B1 B2 with glutathione S-transferase delta prepared by the method of Kamisaka, Habig, Ketley, Arias & Jakoby [(1975) Eur. J. Biochem. 60, 153-161] has been demonstrated, as well as its relationship to other previously described transferases.