Selection and early clinical evaluation of the brain-penetrant 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor UE2343 (Xanamem™)

Background and Purpose

Reducing glucocorticoid exposure in the brain via intracellular inhibition of the cortisol‐regenerating enzyme 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1) has emerged as a therapeutic strategy to treat cognitive impairment in early Alzheimer's disease (AD). We sought to discover novel, brain‐penetrant 11β‐HSD1 inhibitors as potential medicines for the treatment of AD.

Experimental Approach

Medicinal chemistry optimization of a series of amido‐thiophene analogues was performed to identify potent and selective 11β‐HSD1 inhibitors with optimized oral pharmacokinetics able to access the brain. Single and multiple ascending dose studies were conducted in healthy human subjects to determine the safety, pharmacokinetic and pharmacodynamic characteristics of the candidate compound.

Results

UE2343 was identified as a potent, orally bioavailable, brain‐penetrant 11β‐HSD1 inhibitor and selected for clinical studies. No major safety issues occurred in human subjects. Plasma adrenocorticotropic hormone was elevated (a marker of systemic enzyme inhibition) at doses of 10 mg and above, but plasma cortisol levels were unchanged. Following multiple doses of UE2343, plasma levels were approximately dose proportional and the terminal t_1/2 ranged from 10 to 14 h. The urinary tetrahydrocortisols/tetrahydrocortisone ratio was reduced at doses of 10 mg and above, indicating maximal 11β‐HSD1 inhibition in the liver. Concentrations of UE2343 in the CSF were 33% of free plasma levels, and the peak concentration in CSF was ninefold greater than the UE2343 IC₅₀.

Conclusions and Implications

UE2343 is safe, well tolerated and reaches the brain at concentrations predicted to inhibit 11β‐HSD1. UE2343 is therefore a suitable candidate to test the hypothesis that 11β‐HSD1 inhibition in brain improves memory in patients with AD.

Lansoprazole pharmacokinetics differ in patients with oesophagitis compared to healthy volunteers

AIM

To compare the pharmacokinetics of lansoprazole in patients with reflux oesophagitis and in healthy volunteers, after a single dose and at steady-state.

PATIENTS AND METHODS

A 30 mg dose of lansoprazole was administered orally daily for 7 days in eight healthy male volunteers aged 21-24 years, and in 16 patients aged 29-65 years with grade 2 or 3 reflux oesophagitis. The pharmacokinetics were assessed over the 24 h dose interval following the first dose and again after the 7th dose.

RESULTS

Within both the patient and volunteers groups, there were no significant differences between day 1 and day 7 in any of the pharmacokinetic parameters including maximum concentration (Cmax), area under the concentration-time curve (AUC), and terminal half-life of elimination (t(1/2)). However, on both days 1 and 7, values were significantly higher in the patients than in the healthy volunteers. On day 7, Cmax was 1343 ng/mL in patients compared with 765 ng/mL in healthy volunteers, AUC was 3458 ng.h/mL vs. 1350 ng.h/mL and t(1/2) was 1.62 h vs. 0.90 h.

CONCLUSION

The differences in results for the pharmacokinetics reflect reduced lansoprazole clearance in the patient group. Other research has not found a difference in pharmacokinetics when comparing healthy volunteers with patients with acid-related disorders. The difference in lansoprazole clearance in this study may be related to a variety of factors that are different in patients compared with young normal volunteers, such as age, gender, other drugs, and reduced general well-being.

The prevalence of Chlamydia trachomatis in a young, sexually-active population

A prospective study was carried out to determine the prevalence of Chlamydia trachomatis among 1000 sexually-active women at the Family Planning Association Clinic in Melbourne. This organism was isolated from the cervices of 5.1% of screened women. The women were surveyed about their sexual and gynaecological history, and symptoms of discharge or pain. It was found that women who gave positive results for the presence of Chlamydia were younger, and had commenced intercourse at an earlier age. Risk factors of multiple sexual partners, cervical ectopy and symptoms of urethritis were identified. We recommend that women who have more than one sexual partner should ask their partners to use condoms or, failing this, undergo annual screening for Chlamydia by immunofluorescent staining.