Phase Ia study of the indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor navoximod (GDC-0919) in patients with recurrent advanced solid tumors

BACKGROUND

Indoleamine-2,3-dioxygenase 1 (IDO1) catalyzes the oxidation of tryptophan into kynurenine and is partially responsible for acquired immune tolerance associated with cancer. The IDO1 small molecule inhibitor navoximod (GDC-0919, NLG-919) is active as a combination therapy in multiple tumor models.

METHODS

This open-label Phase Ia study assessed safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary anti-tumor activity of navoximod in patients with recurrent/advanced solid tumors, administered as 50-800 mg BID on a 21/28 day and at 600 mg on a 28/28 day schedule. Plasma kynurenine and tryptophan were longitudinally evaluated and tumor assessments were performed.

RESULTS

Patients (n = 22) received a median of 3 cycles of navoximod. No maximum tolerated dose was reached. One dose-limiting toxicity of Grade 4 lower gastrointestinal hemorrhage was reported. Adverse events (AEs) regardless of causality in ≥20% of patients included fatigue (59%), cough, decreased appetite, and pruritus (41% each), nausea (36%), and vomiting (27%). Grade ≥ 3 AEs occurred in 14/22 patients (64%), and were related to navoximod in two patients (9%). Navoximod was rapidly absorbed (Tmax ~ 1 h) and exhibited dose-proportional increases in exposure, with a half-life (t1/2 ~ 11 h) supportive of BID dosing. Navoximod transiently decreased plasma kynurenine from baseline levels with kinetics consistent with its half-life. Of efficacy-evaluable patients, 8 (36%) had stable disease and 10 (46%) had progressive disease.

CONCLUSIONS

Navoximod was well-tolerated at doses up to 800 mg BID decreasing plasma kynurenine levels consistent with its half-life. Stable disease responses were observed.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02048709 .

Randomized trial showing efficacy and safety of twice-daily remogliflozin etabonate for the treatment of type 2 diabetes

We compared the efficacy of twice-daily doses of remogliflozin etabonate (RE) and once-daily pioglitazone with placebo for reduction in glycated haemoglobin (HbA1c) concentration. In this 12-week, double-blind, randomized, active- and placebo-controlled trial, 336 treatment-naïve subjects with type 2 diabetes and an HbA1c of 7.0-9.5% (53-80 mmol/mol) were randomized to RE (50, 100, 250, 500 or 1000 mg twice daily), matching placebo or 30 mg pioglitazone once daily. The primary endpoint was change in HbA1c from baseline. Other endpoints included changes in body weight, lipid levels, safety and tolerability. RE produced a decreasing dose response in HbA1c at week 12 (p < 0.001), with reductions in HbA1c versus placebo ranging from 0.64 to 1.07% (p < 0.001). Statistically significant reductions in body weight for RE compared with placebo were also observed. Twice-daily RE resulted in a dose-ordered improvement in glycaemic control and was generally well tolerated.

Randomized efficacy and safety trial of once-daily remogliflozin etabonate for the treatment of type 2 diabetes

The sodium-dependent glucose transporter 2 (SGLT2) inhibitor remogliflozin etabonate (RE) was evaluated in a 12-week, double-blind, randomized, placebo- and active-controlled, parallel-group study. A total of 252 newly diagnosed and drug-naïve people with type 2 diabetes and glycated haemoglobin (HbA1c) concentrations of 7.0-≤9.5% (53-80 mmol/mol) were recruited. Participants were randomized to RE (100, 250, 500 or 1000 mg once daily or 250 mg twice daily), placebo or 30 mg pioglitazone once daily. The primary endpoint was change in HbA1c concentration from baseline. Secondary endpoints included changes in fasting plasma glucose, body weight and lipid profiles, safety and tolerability. We observed a statistically significant trend in the RE dose-response relationship for change from baseline in HbA1c at week 12 (p < 0.047). RE was generally well tolerated and no effects on LDL cholesterol were observed.

Acute myelogenous leukemia patients are at low risk for invasive fungal infections after high-dose cytarabine consolidations and thus do not require prophylaxis

We evaluated the frequency of invasive fungal infections (IFI), the frequency of empirical antifungal use (EAFU), and the efficacy of fluconazole prophylaxis on IFI and EAFU after high-dose cytarabine (HiDAC) consolidations. Twenty-seven acute myelogenous leukemia patients in their first complete remission received 76 cycles of HiDAC (median cycle: n = 3). Fluconazole prophylaxis was administered following 44 cycles (fluconazole group) and not given in 32 cycles (control group). IFI (2 episodes) + EAFU (11 episodes) was observed in 13 of 76 cycles (17%); there was no difference between the fluconazole group and the control group (p = 0.469). Neutropenia duration was <13 days in 89% of the 76 cycles and was similar in the fluconazole and control groups (p = 0.845). Neutropenic fever was observed in 34 of the 76 cycles (45%) and was similar in the fluconazole group and the control group (p = 0.43). Although HiDAC cycle 1 was associated with a shorter neutropenia duration, there was no association between HiDAC cycle numbers and neutropenic fever or IFI + EAFU. HiDAC consolidations resulted in a high rate of neutropenic fever, the lack of an appreciable benefit from EAFU, and rare IFI. Most likely because of the low incidence of IFI, use of fluconazole or another antifungal is not warranted in this setting.

Paradoxical insulin-induced increase in gluconeogenesis in response to prolonged hypoglycemia in conscious dogs

The aim of this study was to determine the effects of differing insulin concentrations on the gluconeogenic response to equivalent prolonged hypoglycemia. Insulin was infused intraportally, for 3 h, into normal 18-h fasted conscious dogs at 2 (lower, n = 6) or 8 mU.kg-1.min-1 (high, n = 7) on separate occasions. This resulted in steady-state arterial insulin levels of 80 +/- 8 and 610 +/- 55 microU/ml, respectively. Glucose was infused during high dose to maintain the hypoglycemic plateau (50 +/- 1 mg/dl) equivalent to lower. Epinephrine (806 +/- 180 vs. 2,589 +/- 260 pg/ml), norepinephrine (303 +/- 55 vs. 535 +/- 60 pg/ml), cortisol (5.8 +/- 1.2 vs. 12.1 +/- 1.5 micrograms/dl), and pancreatic polypeptide (598 +/- 250 vs. 1,198 +/- 150 pg/ml) were all increased (P < 0.05) in the presence of high-dose insulin. Net hepatic glucose production increased significantly from 2.2 +/- 0.3 to 3.8 +/- 0.5 mg.kg-1.min-1 (P < 0.05) during high-dose infusion but remained at basal levels (2.3 +/- 0.4 mg.kg-1.min-1) during lower-dose insulin. During the 3rd h of hypoglycemia, gluconeogenesis accounted for between 42 and 100% of glucose production during high-dose infusion but only 22-52% during lower-dose insulin. Intrahepatic gluconeogenic efficiency, however, increased similarly during both protocols. Lipolysis, as indicated by arterial blood glycerol levels, increased by a greater amount during high- compared with lower-dose insulin infusion. Six hyperinsulinemic euglycemic control experiments (2 or 8 mU.kg-1.min-1, n = 3 in each) provided baseline data. Gluconeogenesis remained similar to basal levels, but lipolysis was significantly suppressed during both series of hyperinsulinemic euglycemic studies. In summary, these data suggest that 1) the important counterregulatory processes of gluconeogenesis and lipolysis can be significantly increased during prolonged hypoglycemia despite an eightfold increase in circulating insulin levels and 2) the amplified gluconeogenic rate present during the hypoglycemic high-dose insulin infusions was caused by enhanced substrate delivery to the liver rather than an increase in intrahepatic gluconeogenic efficiency.

Evidence that the brain of the conscious dog is insulin sensitive

The aim of this study was to determine whether a selective increase in the level of insulin in the blood perfusing the brain is a determinant of the counterregulatory response to hypoglycemia. Experiments were carried out on 15 conscious 18-h-fasted dogs. Insulin was infused (2 mU/kg per min) in separate, randomized studies into a peripheral vein (n = 7) or both carotid and vertebral arteries (n = 8). This resulted in equivalent systemic insulinemia (84 +/- 6 vs. 86 +/- 6 microU/ml) but differing insulin levels in the head (84 +/- 6 vs. 195 +/- 5 microU/ml, respectively). Glucose was infused during peripheral insulin infusion to maintain the glucose level (56 +/- 2 mg/dl) at a value similar to that seen during head insulin infusion (58 +/- 2 mg/dl). Despite equivalent peripheral insulin levels and similar hypoglycemia; steady state plasma epinephrine (792 +/- 198 vs. 2394 +/- 312 pg/ml), norepinephrine (404 +/- 33 vs. 778 +/- 93 pg/ml), cortisol (6.8 +/- 1.8 vs. 9.8 +/- 1.6 micrograms/dl) and pancreatic polypeptide (722 +/- 273 vs. 1061 +/- 255 pg/ml) levels were all increased to a greater extent during head insulin infusion (P < 0.05). Hepatic glucose production, measured with [3-3H]glucose, rose from 2.6 +/- 0.2 to 4.3 +/- 0.4 mg/kg per min (P < 0.01) in response to head insulin infusion but remained unchanged (2.6 +/- 0.5 mg/kg per min) during peripheral insulin infusion. Similarly, gluconeogenesis, lipolysis, and ketogenesis were increased twofold (P < 0.001) during head compared with peripheral insulin infusion. Cardiovascular parameters were also significantly higher (P < 0.05) during head compared with peripheral insulin infusion. We conclude that during hypoglycemia in the conscious dog (a) the brain is directly responsive to physiologic elevations of insulin and (b) the response includes a profound stimulation of the autonomic nervous system with accompanying metabolic and cardiovascular changes.

Economic issues in managed care

Economic issues abound in managed care. The advent of health insurance in the United States, which was created to ensure payment to hospitals, diminished an early emphasis on charity care. Escalating health care costs have ensued. Today, economic considerations dictate the need to control health care expenditures while guaranteeing responsible care. Managed care organizations can achieve both goals by establishing financial partnerships with physicians while instituting quality-control audits, management review teams, and home-care arrangements.

Effects of hyperinsulinemia on the subsequent hormonal response to hypoglycemia in conscious dogs

The aim of this study was to determine if differing periods of prior hyperinsulinemic nonhypoglycemia can modify the subsequent counterregulatory response to hypoglycemia. Experiments were carried out on 19 normal 18-h fasted conscious dogs. Insulin was infused intraportally at 8 mU.kg-1.min-1 for 3 h on two occasions and 3.5 h on a third separate occasion. This resulted in similar steady-state arterial insulin levels during each protocol (4,370 +/- 433 pmol/l). Each animal was maintained at a similar plasma glucose nadir (2.8 +/- 0.6 mmol/l) for 2 or 2.5h, depending on the protocol. In protocol I (n = 7) plasma glucose was allowed to fall to the desired hypoglycemic plateau by 30 min. In a second group of dogs (protocol II, n = 5) there was a 30-min period of euglycemic hyperinsulinemia followed by a 30-min fall (similar to protocol I) in plasma glucose. In a third group of dogs (protocol III, n = 7), there was an initial 15-min period of euglycemic hyperinsulinemia followed by a 45-min fall in plasma glucose. Differing periods of euglycemic hyperinsulinemia had distinct effects on subsequent counterregulation. During the final 2 h of hypoglycemia the incremental area under the curve (AUC) for glucagon was significantly greater in protocol I vs. II (3.0 +/- 1.0, -0.5 +/- 0.2 micrograms.l-1.min-1, P < 0.02, respectively). Conversely, catecholamine levels were increased in protocol II (30 min prior hyperinsulinemic euglycemia) compared with protocol I (epinephrine 1,448 +/- 268, 855 +/- 119 nmol.l-1.min-1; norepinephrine 244 +/- 30, 166 +/- 23 nmol.l-1.min-1, respectively, P < 0.05). During protocol III, glucagon and catecholamine levels were intermediate between protocols I (no euglycemic hyperinsulinemia) and II (30 min euglycemic hyperinsulinemia).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of differing insulin levels on response to equivalent hypoglycemia in conscious dogs

The aim of this study was to determine if differing concentrations of insulin can modify the counterregulatory response to equivalent hypoglycemia. Insulin was infused intraportally into normal 18-h-fasted conscious dogs at 2 (low, n = 6) or 8 mU.kg-1.min-1 (high, n = 7) on separate occasions. This resulted in steady-state arterial insulin levels of 80 +/- 8 and 610 +/- 55 microU/ml, respectively. Glucose was infused during the high dose to maintain plasma glucose similar to low (50 +/- 1 mg/dl). Despite similar plasma glucose levels, epinephrine (2,589 +/- 260, 806 +/- 180 pg/ml), norepinephrine (535 +/- 60, 303 +/- 55 pg/ml), cortisol (12.1 +/- 1.5, 5.8 +/- 1.2 micrograms/dl), and pancreatic polypeptide (1,198 +/- 150, 598 +/- 250 pg/ml) were all increased in the presence of high-dose insulin (P < 0.05). Glucagon levels were similar during both insulin infusions. Hepatic glucose production, measured with [3-3H]-glucose, rose from 2.6 +/- 0.2 to 4.7 +/- 0.3 mg.kg-1.min-1 in response to high insulin (P < 0.01) but remained unchanged, 3.0 +/- 0.5 mg.kg-1.min-1, during low-dose infusions. Six hyperinsulinemic euglycemic control experiments (2 or 8 mU.kg-1.min-1, n = 3 in each) provided baseline data. By the final hour of the high-dose euglycemic clamps, cortisol (2.4 +/- 0.4 to 4.8 +/- 0.8 micrograms/dl) and norepinephrine (125 +/- 34 to 278 +/- 60 pg/ml) had increased (P < 0.05) compared with baseline. Plasma epinephrine levels remained unchanged during both series of euglycemic studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Cord blood thyrotropin screening for primary hypothyroidism on Caribbean island: a rapid communication

Screening programs using determinations of serum thyroxine have demonstrated that congenital hypothyroidism occurs in one in 4,000 live births in North America. More than 90 percent of affected infants have primary hypothyroidism with elevated plasma thyrotropin (TSH) levels. Since the feasibility of newborn screening and incidence of congenital hypothyroidism in other less well developed areas of the world is not well defined, a study was undertaken of neonatal primary hypothyroid screening infants born on the Caribbean island of St. Lucia in the Lesser Antilles. Three hundred thirteen cord blood samples were collected on filter paper and transported 3,000 miles to Loyola University of Chicago, Stritch School of Medicine (LUMC). From LUMC, the samples were transported to the Illinois State Metabolic Screening Laboratory for determination of TSH by radioimmunoassay (RIA). In this group of newborns, the mean TSH level in cord blood was 10.23 +/- 0.29 microIU per ml (SEM). It is concluded that screening programs for neonatal primary hypothyroidism can be performed using reference laboratories far removed from the population under observation.