Glen Apseloff

Pharmacokinetics of anthocyanins and ellagic acid in healthy volunteers fed freeze-dried black raspberries daily for 7 days.

Eleven subjects completed a clinical trial to determine the safety/tolerability of freeze‐dried black raspberries (BRB) and to measure, in plasma and urine, specific anthocyanins‐cyanidin‐3‐glucoside, cyanidin‐3‐sambubioside, cyanidin‐3‐rutinoside, and cyanidin‐3‐xylosylrutinoside, as well as ellagic acid. Subjects were fed 45 g of freeze‐dried BRB daily for 7 days. Blood samples were collected predose on days 1 and 7 and at 10 time points postdose. Urine was collected for 12 hours predose on days 1 and 7 and at three 4‐hour intervals postdose. Maximum concentrations of anthocyanins and ellagic acid in plasma occurred at 1 to 2 hours, and maximum quantities in urine appeared from 0 to 4 hours. Overall, less than 1% of these compounds were absorbed and excreted in urine. None of the pharmacokinetic parameters changed significantly between days 1 and 7. In conclusion, 45 g of freeze‐dried BRB daily are well tolerated and result in quantifiable anthocyanins and ellagic acid in plasma and urine.

The importance of measuring cotinine levels to identify smokers in clinical trials.

First‐time‐in‐humans studies of drugs (phase I) typically exclude unsuitable volunteers by testing for recreational drugs. However, volunteers are usually not screened for cotinine, a metabolite of nicotine, even though tobacco products may alter pharmacokinetic and pharmacodynamic parameters and withdrawal from tobacco may cause additional adverse events. The accuracy of personal histories as means of excluding smokers was examined prospectively in three phase I units in the northeastern, midwestern, and southwestern United States. In studies intended for nonsmokers, 45 of 282 purported nonsmokers screened before enrollment tested positive for cotinine. This suggests that personal histories are unreliable in determining tobacco use in clinical trials designated for nonsmokers.

Prevention of murine cardiac allograft rejection with gallium nitrate : Comparison with anti-CD4 monoclonal antibody

Gallium nitrate (GN) was evaluated for its ability to interfere with a cute rejection of DBA/2-->C57BL/6 heterotopic cardiac allografts, in comparison with the depleting anti-CD4 mAb, GK1.5. The administration of GN for 30 days (s.c. 30 mg/kg elemental gallium on days 0 and 3, 10 mg/kg every third day) resulted in >60-day graft survival in 78% (25 of 32) of the graft recipients, whereas 2 perioperative injections of anti-CD4 monoclonal antibody (mAb) resulted in >60-day graft survival in 58% (24 of 41) of the graft recipients. Serum gallium levels peaked at about 2000 ng/ml after 2-3 weeks of treatment and decreased to about 300 ng/ml by day 60, a level that was maintained for at least 30 more days. During the early posttransplant period, 25% of GN-treated grafts, but not anti-CD4 mAb-treated grafts, exhibited an unusual, transient reduction in graft impulse strength, suggesting a transient rejection response. Macroscopically, the long-surviving (>60 days) grafts from either treatment group exhibited none of the features of rejecting allografts. Histologically, they exhibited minor edema and rare epicardial inflammation but no tissue necrosis. However, there were vascular changes in allografts from GN-treated mice, including altered endothelial morphology, associated with moderate intimal hyperplasia and mild perivascular leukocytic infiltration. Allografts from anti-CD4 mAb-treated mice exhibited prominent neointimal hyperplasia associated with endothelial morphologic changes and prominent vascular and perivascular leukocytic infiltration. In general, both GN and anti-CD4 mAb promoted long-term allograft survival, but these allografts displayed the histopathologic signs of ongoing inflammation and chronic allograft rejection.

Induction of Fluconazole Metabolism by Rifampin: In Vivo Study in Humans

The effects of rifampin on the pharmacokinetics of fluconazole were analyzed in an open‐label, placebo‐controlled, parallel study. Sixteen healthy male volunteers, randomized into two groups, received 200 mg of oral fluconazole on days 1 and 22. On days 8 through 27, group I received oral rifampin, 600 mg/d, and group II received placebo. Fluconazole in serum was analyzed by HPLC. On days 1 and 22, respectively, the AUC (μg · hr/mL) (mean ± SD) was 160.5 ± 19.5 and 124 ± 22.2 in group I, 152 ± 25 and 152.8 ± 33.9 in group II; the Kel (hr−1) was .0211 ± .0030 and .0264 ± .0040 in group I, .0219 ± .0036 and .0216 ± .0053 in group II. Cmax and Tmax did not change significantly in either group. Urinary 6β‐hydroxycortisol/cortisol increased from 3.47 ± 1.04 to 15.2 ± 5.07 in group I, but was unchanged (3.54 ± 1.33–4.26 ± 2.36) in group II on days 1 and 22, respectively. The findings in this study indicate that rifampin induces the metabolism of fluconazole.

Use of gallium to treat Paget's disease of bone: a pilot study

The effects of gallium nitrate on bone turnover were evaluated in four patients with active Pagets disease. Treatment with gallium nitrate (100 mg/m2 daily for 5 days, intravenously in 5% glucose) significantly reduced serum calcium, serum phosphate, urinary calcium, and the ratio of maximum tubular reabsorption of phosphate to glomerular filtration rate in each patient. Serum parathyroid hormone levels rose. The findings suggest that the fall in serum calcium caused secondary hyperparathyroidism, resulting in a fall in serum phosphate. Serum alkaline phosphatase and urinary hydroxyproline levels fell substantially, showing that gallium effectively suppressed bone turnover. The fall in hydroxyproline excretion preceded that in serum alkaline phosphatase, suggesting that suppression of bone resorption by osteoclasts preceded that of bone formation by osteoblasts. Alkaline phosphatase levels remained low throughout follow-up (85-141 days), so the effect of gallium seems to be long-lasting.

Gut Hormone Pharmacology of a Novel GPR119 Agonist (GSK1292263), Metformin, and Sitagliptin in Type 2 Diabetes Mellitus: Results from Two Randomized Studies

GPR119 receptor agonists improve glucose metabolism and alter gut hormone profiles in animal models and healthy subjects. We therefore investigated the pharmacology of GSK1292263 (GSK263), a selective GPR119 agonist, in two randomized, placebo-controlled studies that enrolled subjects with type 2 diabetes. Study 1 had drug-naive subjects or subjects who had stopped their diabetic medications, and Study 2 had subjects taking metformin. GSK263 was administered as single (25–800 mg; n = 45) or multiple doses (100–600 mg/day for 14 days; n = 96). Placebo and sitagliptin 100 mg/day were administered as comparators. In Study 1, sitagliptin was co-administered with GSK263 or placebo on Day 14 of dosing. Oral glucose and meal challenges were used to assess the effects on plasma glucose, insulin, C-peptide, glucagon, peptide tyrosine-tyrosine (PYY), glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). After 13 days of dosing, GSK263 significantly increased plasma total PYY levels by ∼five-fold compared with placebo, reaching peak concentrations of ∼50 pM after each of the three standardized meals with the 300 mg BID dose. Co-dosing of GSK263 and metformin augmented peak concentrations to ∼100 pM at lunchtime. GSK263 had no effect on active or total GLP-1 or GIP, but co-dosing with metformin increased post-prandial total GLP-1, with little effect on active GLP-1. Sitagliptin increased active GLP-1, but caused a profound suppression of total PYY, GLP-1, and GIP when dosed alone or with GSK263. This suppression of peptides was reduced when sitagliptin was co-dosed with metformin. GSK263 had no significant effect on circulating glucose, insulin, C-peptide or glucagon levels. We conclude that GSK263 did not improve glucose control in type 2 diabetics, but it had profound effects on circulating PYY. The gut hormone effects of this GPR119 agonist were modulated when co-dosed with metformin and sitagliptin. Metformin may modulate negative feedback loops controlling the secretion of enteroendocrine peptides. Trial Registration: Clinicaltrials.gov NCT01119846 Clinicaltrials.gov NCT01128621

Death from a morphine infusion during a sickle cell crisis

A 15-year-old boy died during a vaso-occlusive sickle cell crisis after having received a prolonged infusion of morphine. Even in therapeutic doses, narcotics may cause significant respiratory acidosis and hypoxemia, enhancing polymerization of hemoglobin SS and thereby promoting sickling and vaso-occlusion. When narcotics are used during a sickle cell crisis, the best method is pharmacokinetically based patient-controlled analgesia.

Suppression of experimental autoimmune encephalomyelitis by gallium nitrate

We examined the effect of gallium (Ga) nitrate on the development of the development of experimental autoimmune encephalomyelitis (EAE). Weekly subcutaneous injections of 10-30 mg/kg prevented clinical signs as well as histopathological changes of EAE. The optimal timing of a single injection of Ga was 6 days after induction of EAE, with amelioration also apparent following a single injection on day 3 or 9 but not day 12. Ga administered in vivo suppressed myelin basic protein (MBP) and purified protein derivative-specific lymphocyte proliferative responses in vitro. Addition of Ga to MBP-specific T lymphocyte line cultures at various times after initiation of culture revealed that Ga exerts an effect at an early stage of cellular activation.

Severe neutropenia among healthy volunteers given rifabutin in clinical trials

To the Editor: Rifabutin is a medication approved by the Food and Drug Administration for the prevention of disseminated Mycobacterium avium complex infections in patients with acquired immunodeficiency syndrome. In a clinical trial conducted in 1995 and published in 1996 and 1998, thrombocytopenia and severe neutropenia (grade 4, absolute neutrophil counts 500 cells/mm) occurred among healthy volunteers receiving a standard dose of 300 mg/d of this drug. The 14-day study was terminated after 10 days because of neutropenia, fevers as high as 103.0°F, and other adverse events. Neutrophil counts, obtained only after 1 subject appeared ill, were documented to be as low as 180 cells/mm. Of 18 subjects receiving rifabutin alone or in combination with azithromycin or clarithromycin, 14 (78%) were observed to have neutropenia, in contrast to 0 of 12 receiving azithromycin or clarithromycin alone, and all of those with absolute neutrophil counts of 600 cells/mm or lower (n 7) also had fevers of 101.0°F or higher. Five of the subjects were treated with granulocyte-macrophage colony-stimulating factor, and 3 were hospitalized. Despite these and other reports of grade 4 neutropenia among healthy volunteers receiving standard doses of rifabutin, investigators continue to expose this population to the drug in clinical trials, and not surprisingly, these more recent studies describe grade 3 and 4 neutropenia as an adverse event among the participants. Hafner et al described neutropenia as the most frequently reported adverse event after administration of rifabutin, occurring in 33 of 50 subjects and ranging from mild to potentially life-threatening. In a study comparing rifabutin with rifampicin, LeBel et al demonstrated that the former caused a significantly greater decrease in absolute neutrophil counts, total white blood cell counts, and platelet counts. In addition, Gonzalez-Montaner et al reported the death of a patient with tuberculosis (who was negative for human immunodeficiency virus) in a clinical trial, resulting from a brain hemorrhage caused by thrombocytopenia. In all of these clinical trials, subjects received 300 mg/d rifabutin. The package insert for rifabutin states that 2% of patients in clinical trials discontinued use because of neutropenia. It further states that in two of the clinical trials the frequency of neutrophil counts lower than 750 cells/mm was 25% among patients receiving rifabutin (n 566), as compared with 20% among control subjects receiving placebo (n 580). However, there is no mention of when and how frequently hematology studies were obtained. The package insert provides no specific instructions regarding monitoring for neutropenia but instead recommends that physicians should consider obtaining hematologic studies periodically. This is not adequate. Regardless of whether an optimal monitoring scheme is known for the drug, a reasonable recommendation should be provided. For example, the package insert might recommend obtaining a complete blood cell count 1 week after initiation of therapy and then at 2to 4-week intervals. The package insert should also be updated to describe the high incidence of neutropenia observed in recent clinical trials, as well as the early onset of this adverse event. On the basis of their observations of severe neutropenia within 1 to 2 weeks after dosing healthy volunteers with rifabutin, Apseloff et al recommended a change in 1996 to provide guidelines for monitoring complete blood cell counts. That recommendation should now be implemented. Furthermore, neutropenia should be mentioned in the “warnings” section of the package insert rather than only the “precautions” section; this would be consistent with the US Code of Federal Regulations (21CFR201.57e), which states that the “. . .labeling shall be revised to include a warning as soon as there is reasonable evidence of an association of a serious hazard with a drug.” As a result of the lack of clear information in the package insert for rifabutin, neither healthy volunteers recruited for clinical trials nor institutional review boards may be fully informed of the risk of neutropenia caused by the drug. Like prescribing physicians, investigators and institutional review board members sometimes rely solely on the package insert for information regarding the risks of medications approved by the Food and Drug Administration. Unfortunately, relying on the rifabutin package insert to describe the risks of neutropenia to healthy volunteers in a clinical trial may be misleading. Even a review of the literature may be incomplete in informing physicians about the risk of neutropenia associated with rifabutin. A recently published article describing a clinical trial that caused grade 4 neutropenia in healthy volunteers did not mention this adverse event in the abstract, and a standard literature search of “rifabutin” and “neutropenia” does not find this reference. Currently, the risk of neutropenia caused by rifabutin has not been optimally conveyed to physicians, patients, researchers, and volunteers in clinical trials. Ideally, persons should not rely solely on a package insert for information regarding potential hazards of a medication, but regardless, the package insert should contain all relevant information pertaining to serious risks. Perhaps, for rifabutin, this information will be included in the near future.

Effect of sertraline on protein binding of warfarin.

SummaryThe effect of sertraline on the plasma protein binding of warfarin was investigated in a nonblinded randomised placebo-controlled parallel trial in 12 healthy male volunteers. The study participants received single doses of warfarin before administration of sertraline or placebo and again after sertraline or placebo had been administered for 22 days.Treatment with sertraline for 26 days increased the area under the mean prothrombin time vs time curve by 145 sec · h (7.9%), compared with a decrease of 17 sec · h (−1.0%) in the placebo group. Although statistically significant (p=0.02), this difference was not felt to be clinically meaningful. There appeared to be a slight delay in the normalisation of the prothrombin time in the sertraline-treated group after the second dose of warfarin, which also would not be expected to be clinically significant.After 22 days, a statistically significant (p=0.02) increase in unbound warfarin was observed in the sertraline group compared with the placebo-treated individuals. Neither the change in prothrombin time nor the change in plasma protein binding were considered to have any clinical relevance; however, good clinical practice dictates that prothrombin time should be monitored in patients treated concurrently with warfarin and sertraline to ensure that the integrity of coagulation response is maintained.The metabolism of warfarin is principally mediated by the cytochrome P450 (CYP) isoenzyme CYP2C9/10. Thus, sertraline appears to have a minimal effect on the CYP2C9/10 isoenzyme.