Population Modeling of Selexipag Pharmacokinetics and Clinical Response Parameters in Patients With Pulmonary Arterial Hypertension

Selexipag (Uptravi) is an oral selective IP prostacyclin receptor agonist approved for the treatment of pulmonary arterial hypertension (PAH). The pivotal GRIPHON study was the largest clinical study ever conducted in PAH patients, providing long‐term data from 1,156 patients. PAH comedication did not affect exposure to selexipag, while exposure to its active metabolite ACT‐333679 was reduced by 30% when taken in combination, clinically not relevant in the context of individual dose up‐titration. Using log‐linear regression models linking model‐predicted steady‐state exposure to pharmacodynamics (PD), exposure to selexipag and ACT‐333679 showed some statistically significant, albeit not clinically relevant, effects on exercise capacity, laboratory values, and the occurrence of prostacyclin‐related adverse events, but not on vital signs or adverse events denoting hemorrhage. Using suitable modeling techniques, the GRIPHON study yielded clinically relevant data with limited burden of pharmacokinetics (PK) blood sampling, demonstrating that PK/PD modeling enables firm conclusions even with sparse PK and PD sampling.

The effect of DXA scanning on clinical decision making by general practitioners: a randomized, prospective trial of direct access versus referral to a hospital consultant

The objective of the study was to assess the impact of direct access DXA scanning (DADS) upon GPs' management decisions in patients considered to be at risk of osteoporosis. It was designed as a randomized, prospective, parallel group trial, set within the primary care environment and a university teaching hospital. The participants were 330 patients aged 31 to 89 years from 18 general practices in Edinburgh. Patients were randomized to either DADS or to the current system of specialist referral (controls). The primary outcome measure was frequency of change of management after DXA scanning. Secondary outcome measures were: change in health status, adherence to therapy, clinical events and resource use at one-year follow-up. The primary outcome was that 60% each of DADS patients (98/165) and controls (99/165) had changes in management following DXA scanning. In 30% of patients (12/41) in whom GPs had proposed changing management even in the absence of a scan, different therapy was chosen after the scan (no difference between DADS and control groups). There was an improvement in health utility (p =0.014 for both groups combined), differing slightly between the two groups even after age correction (p =0.014). 68% of the DADS group and 70% of controls were adherent to therapy after one year. In terms of clinical events, at one year there was one major adverse event (control group patient), 5 new fractures in the DADS group and 3 in controls - there were no hip fractures in this study. With regard to resource use, there were 24 referrals to hospital specialist after DXA scanning among the DADS group, vs 12 among controls (p < 0.05). The total number of visits to health professionals was 525 in DADS and 585 in controls (p=ns); mean waiting time from randomization to receipt of report/clinic letter was 4 weeks for DADS vs 13 weeks for controls( p < 0.0001). In conclusion, DXA scanning resulted in management change in at least 60% of cases. Direct access does not result in a clinical outcome significantly different from a consultant led service, and is more economically efficient than the current model of hospital referral.

Inhibition of human monocyte respiratory burst, degranulation, phospholipid methylation and bactericidal activity by pneumolysin

The interaction between the pneumococcal toxin pneumolysin and human monocytes was examined. At non-cytotoxic concentrations (0.5-2.5 HU/10(6) cells) pneumolysin depressed the oxygen-dependent respiratory burst in monocytes, induced by opsonized zymosan or phorbol myristate acetate (PMA). This included depressed hexose-monophosphate shunt activity and hydrogen peroxide production. The toxin also depressed the ability of monocytes to degranulate (measured by release of lysozyme) in response to the above stimuli. Phospholipid transmethylation was also markedly decreased by pretreating monocytes with pneumolysin. These effects on monocyte functions were accompanied by a decreased ability of pneumolysin-treated monocytes to kill Streptococcus pneumoniae, the organism that produces the toxin. Cholesterol, which inhibits the haemolytic activity of the toxin, was shown to abrogate the effects of pneumolysin on monocytes.

A short, retarded child with a deletion of the short arm of chromosome 18 (18p-)

A small black girl with a deletion of chromosome 18 is described. She is mentally retarded and small for her age, and has severe dental decay, hypertelorism, and epicanthic folds. Her IgA is normal. Her bone age is retarded.