Safety and pharmacokinetics of ONC201 (dordaviprone) administered two consecutive days per week in pediatric patients with H3 K27M-mutant glioma

BACKGROUND

This study evaluated the safety and pharmacokinetics (PK) of oral ONC201 administered twice-weekly on consecutive days (D1D2) in pediatric patients with newly diagnosed DIPG and/or recurrent/refractory H3 K27M glioma.

METHODS

This phase 1 dose-escalation and expansion study included pediatric patients with H3 K27M-mutant glioma and/or DIPG following ≥1 line of therapy (NCT03416530). ONC201 was administered D1D2 at 3 dose levels (DLs; -1, 1, and 2). The actual administered dose within DLs was dependent on weight. Safety was assessed in all DLs; PK analysis was conducted in DL2. Patients receiving once-weekly ONC201 (D1) served as a PK comparator.

RESULTS

Twelve patients received D1D2 ONC201 (DL1, n = 3; DL1, n = 3; DL2, n = 6); no dose-limiting toxicities or grade ≥3 treatment-related adverse events occurred. PK analyses at DL2 (D1-250 mg, n = 3; D1-625 mg, n = 3; D1D2-250 mg, n = 2; D1D2-625 mg, n = 2) demonstrated variability in Cmax, AUC0-24, and AUC0-48, with comparable exposures across weight groups. No accumulation occurred with D1D2 dosing; the majority of ONC201 cleared before administration of the second dose. Cmax was variable between groups but did not appear to increase with D1D2 dosing. AUC0-48 was greater with D1D2 than once-weekly.

CONCLUSIONS

ONC201 given D1D2 was well tolerated at all DLs and associated with greater AUC0-48.

Safety, tolerability, and pharmacokinetics of oral and intravenous administration of GSK1322322, a peptide deformylase inhibitor

GSK1322322 is the first in a new class of antibiotics that targets peptide deformylase (PDF), an essential bacterial enzyme required for protein maturation. This randomized, double-blind, placebo-controlled, eight-cohort phase I trial enrolled 62 healthy volunteers to assess safety, tolerability, and pharmacokinetic profiles of GSK1322322. GSK1322322 was administered as a single oral or intravenous (IV) dose, escalating from 500 to 3,000 mg or repeat IV doses escalating from 500 to 1,500 mg twice daily. Upon repeat IV administration, GSK1322322 exhibits linear pharmacokinetics over time upon repeat doses as shown by time-invariant pharmacokinetics. A dose-proportional increase in area under concentration-time curve was observed after single or repeat IV dosing, whereas clearance at steady state remained generally unchanged across doses. There was minimal accumulation of GSK1322322 after repeat IV twice-daily administration. After oral tablet doses of GSK1322322 1,000 and 1,500 mg, absolute bioavailability was 69% and 56%, respectively. GSK1322322 administration at single and repeat IV doses and at supratherapeutic single IV doses of 2,000 and 3,000 mg was associated with mild-to-moderate drug-related adverse events. On the basis of the pharmacokinetics and tolerability demonstrated in this study, GSK1322322 has the potential to become the first-in-class PDF inhibitor for clinical use.

Safety, tolerability and pharmacokinetics of repeat dosing of the antibiotic GSK1322322, a peptide deformylase inhibitor: a randomized placebo-controlled study

OBJECTIVES

GSK1322322 is a potent inhibitor of peptide deformylase, an essential bacterial enzyme required for protein maturation. In this two-part, double-blind, randomized, placebo-controlled, Phase 1 study (study identifier: PDF112668), the safety, tolerability and pharmacokinetics of single and repeat oral-dose GSK1322322 (500-1500 mg) in healthy adult and elderly volunteers were evaluated.

PATIENTS AND METHODS

Part A included GSK1322322 doses of 500, 750, 1000 and 1500 mg in healthy adults; Part B evaluated 1000 mg of GSK1322322 in healthy elderly volunteers. Volunteers received a single morning dose of a powder-in-bottle formulation of GSK1322322 or placebo on day 1, no dosing on day 2 and twice-daily dosing on days 3-12.

RESULTS

Of 52 enrolled volunteers, 40 and 12 volunteers were treated with GSK1322322 and placebo, respectively. Mean plasma GSK1322322 trough concentration increased with increasing dose and reached steady-state after 2 days of repeat dosing. After single dosing of GSK1322322, maximum plasma concentration and exposure (AUC) were dose proportional from 500 to 1500 mg. However, after repeat dosing, AUC values at steady-state increased slightly more than proportionally, possibly because of a slightly longer terminal elimination t½ after repeat dosing (compared with single-dose t½) at higher doses (1000 and 1500 mg). There was no age effect or diurnal variation in the GSK1322322 pharmacokinetic profile. GSK1322322 was generally well tolerated-all adverse events were mild to moderate in intensity.

CONCLUSIONS

Repeat oral GSK1322322 (500-1500 mg) for 10 days was well tolerated. These data warrant further clinical investigation of GSK1322322.

The Influence of Norfloxacin and Metronidazole on the Disposition of Mycophenolate Mofetil

The objective of this study was to investigate the effect of concurrent antibiotic administration on the disposition of mycophenolic acid (MPA) and mycophenolic acid glucuronide (MPAG) after oral administration of mycophenolate mofetil (MMF) in healthy subjects. Eleven healthy subjects were enrolled. The study was divided into 4 treatment periods. Subjects received MMF as a single oral 1-g dose alone and were then randomized to 3 antibiotic treatment periods. The 3 periods included norfloxacin, metronidazole, and a combination of norfloxacin and metronidazole. Antibiotic treatment was started 3 days prior to each MMF pharmacokinetic study day and was given for a total of 5 days. On day 4 of each antibiotic phase, subjects received a single 1-g oral dose of MMF. Plasma and urine samples were obtained over 48 hours after the MMF dose in all treatment periods and were quantitatively measured for MPA and MPAG. Pharmacokinetic parameters for MPA and MPAG were determined for all periods. Compared to MMF alone, the area under the plasma concentration versus time curve (AUC) of MPA was reduced by an average of 10%, 19%, and 33% when given with norfloxacin, metronidazole, and norfloxacin plus metronidazole, respectively. The AUC of MPAG was also reduced on average by 10%, 27%, and 41% in the corresponding periods. The combination of norfloxacin and metronidazole significantly reduced the AUC of MPA and MPAG in healthy subjects. This likely occurs as a result of reduced enterohepatic recirculation.

Pharmacokinetics of lamivudine in subjects receiving peritoneal dialysis in end-stage renal failure

AIMS

To establish whether peritoneal dialysis (PD) requires dosing modification from the CL(CR)-corrected lamivudine dose in end-stage renal failure subjects.

METHODS

This was an open-label cohort study. A total of 12 subjects undergoing PD, six continuous ambulatory peritoneal dialysis (CAPD) and six automated peritoneal dialysis (APD), for at least 3 months received lamivudine 10 mg (5 mg ml (-1) x 2 ml) daily for 8 consecutive days, followed by an intensive pharmacokinetic assessment. Urine and dialysate were collected from 0 to 24 h postdose on day 8 where possible. Pharmacokinetic parameters were calculated using noncompartmental techniques.

RESULTS

The plasma pharmacokinetic results demonstrated that peritoneal dialysis clearance (CL(D)) of lamivudine was similar between APD and CAPD patients with median (range) of 0.19 l h(-1) (0.14-0.25) and 0.1 l h(-1) (0.09-0.25), respectively. CL(D) was approximately 1/15th to 1/30th of plasma clearance, demonstrating that peritoneal dialysis does not contribute significantly to overall lamivudine clearance in this patient population. The AUC(0,24 h) of lamivudine given 10 mg daily to APD and CAPD patients was 3430 ng ml(-1) h and 3469 ng ml(-1) h, respectively, similar to historical data obtained in patients with normal renal function administered at the normal dose of 100 mg daily (3781 ng ml(-1) h). There were no clinically significant changes in any safety assessments that were attributable to lamivudine.

CONCLUSIONS

ESRD patients who receive CAPD or APD require no supplemental dosing. These patients should follow the standard dosing reduction for patients infected with HIV or HBV with renal dysfunction.

A 42-Week Open-Label Study to Assess the Pharmacokinetics, Antiretroviral Activity, and Safety of Amprenavir or Amprenavir plus Ritonavir in Combination with Abacavir and Lamivudine for Treatment of HIV-Infected Patients

The pharmacokinetics, antiviral activity, and safety of an amprenavir-ritonavir (APV-RTV) 600/100 mg b.i.d. regimen and an APV-RTV 1200/200 mg q.d. regimen were studied in a human immunodeficiency virus (HIV)-infected population. The geometric least-square mean ratio (90% confidence interval) of steady-state trough concentrations, compared with that of the amprenavir 1200 mg b.i.d. regimen, was 6.08 (4.94-7.49) for the twice-daily APV-RTV regimen, and it was 4.19 (2.90-6.08) for the daily APV-RTV regimen. The regimens were well tolerated, which supports APV-RTV as an option for twice-daily or daily therapy for HIV.

Six-week randomized controlled trial to compare the tolerabilities, pharmacokinetics, and antiviral activities of GW433908 and amprenavir in human immunodeficiency virus type 1-infected patients

This study compared the plasma amprenavir pharmacokinetics of the human immunodeficiency virus (HIV) protease inhibitors amprenavir (Agenerase) 1,200 mg twice daily (BID) and the amprenavir prodrug GW433908, a formulation that substantially reduces the number of tablets per dose compared with amprenavir, at doses of 1,395 mg and 1,860 mg BID, in combination with abacavir 300 mg BID and lamivudine 150 mg BID in patients with HIV infection. Overall, 78 patients received study treatment. Compared with amprenavir 1,200 mg BID, both GW433908 1,395 mg BID and GW433908 1,860 mg BID delivered equivalent steady-state (ss) values for area under the plasma amprenavir concentration-time curve (AUC) at the end of a dosing interval (tau), lower maximum plasma amprenavir concentrations (30% lower), and higher plasma amprenavir concentrations at the end of a dosing interval (28% higher for GW433908 1,395 mg BID and 46% higher for GW433908 1,860 mg BID). Time-variant plasma amprenavir pharmacokinetics were observed with reductions in plasma amprenavir exposure over the first 4 weeks of dosing; the decrease in plasma amprenavir AUC(tau,ss) versus the AUC from 0 h to infinity was 27% for GW43308 1,395 mg, 45% for GW433908 1,860 mg, and 23% for amprenavir 1,200 mg. All three regimens reduced plasma HIV-1 RNA ( approximately 2 log(10) copies/ml) and increased CD4(+) cell counts ( approximately 100 cells/mm(3)) over the initial 28 days. Adverse event profiles were consistent with those previously reported for amprenavir. Although not statistically tested, the GW433908 groups appeared to have fewer gastrointestinal symptoms. In conclusion, the protease inhibitor GW433908 delivered comparable plasma amprenavir concentrations to those delivered by amprenavir 1,200 mg BID. GW433908, in combination with abacavir and lamivudine, demonstrated potent antiviral activity and was generally well tolerated over a 4-week period.

Effects of formulation and dosing strategy on amprenavir concentrations in the seminal plasma of human immunodeficiency virus type 1-infected men

We compared seminal plasma pharmacokinetic data for the investigational amprenavir prodrug GW433908 with those for amprenavir and an amprenavir-ritonavir combination regimen. All 3 regimens resulted in detectable blood plasma and seminal plasma concentrations of amprenavir. The majority of these concentrations were greater than the plasma protein-corrected 50% inhibitory concentration for wild-type human immunodeficiency virus type 1.

Retrospective evaluation of therapies for Staphylococcus aureus endocarditis

We retrospectively evaluated antiinfective therapy for methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) endocarditis in 54 patients who had 57 treatment courses for the disease. Three treatments were assessed: 27 nafcillin-treated courses of MSSA endocarditis, 18 vancomycin-treated courses of MSSA endocarditis, and 11 vancomycin-treated courses of MRSA endocarditis. At baseline, patients with MSSA treated with vancomycin had more chronic conditions (p<0.01), a lower frequency of intravenous drug use (p<0.01), a lower hematocrit concentration (p<0.05), and a higher serum creatinine concentration (p<0.05) than the nafcillin group. Vancomycin-treated patients had a higher complication rate during therapy (p<0.05) and a longer duration in an intensive care unit (p<0.01) than the nafcillin group. The trend was for a higher complete response rate in the nafcillin group (74% vs 50%, p=0.12), but no difference in mortality (22% vs 28%, p=0.73). Patients with MRSA infection treated with vancomycin had higher mortality than those with MSSA who received that drug (55% vs 28%, p=0.24). Patients with vancomycin-treated MSSA endocarditis may have a poorer outcome than those who receive nafcillin, but this may be influenced by different or more severe clinical features.

National survey of once-daily dosing of aminoglycoside antibiotics

To evaluate the scope of once-daily dosing of intravenous aminoglycoside antibiotics, a questionnaire was designed and mailed to a random sample of pharmacy directors at 500 acute care hospitals in the United States. The response rate was 68.4%. Nineteen percent of the respondents reported use of once-daily dosing of aminoglycosides. Affiliation with a pharmacy residency program and the presence of a pharmacokinetic consultation service by the pharmacy department were associated with this practice (p < 0.05). No other statistically significant differences were found. Reported indications, contraindications, and dosing were consistent with those found in the literature. The profession of pharmacy, as demonstrated by pharmacy residency programs and pharmacokinetic consultation services, appears to have been instrumental in implementing this method of dosing aminoglycosides.