Steroidal C-21 heteroaryl thioethers (Part 2): discovery of orally bioavailable selective glucocorticoid receptor modulators (dissociated steroids).

The prednisolone C-21 heteroaryl thioethers have been synthesized and evaluated in cell based transrepression and transactivation assays. Most of the compounds demonstrated weak transactivational activity in both human and rat tyrosineaminotransferase functional assay while keeping potent anti-inflammatory activity. The benzimidazole thioether 7 exhibited comparable anti-inflammatory activity and improved safety profile compared to the classical oral steroid prednisolone.

Steroidal C-21 heteroaryl thioethers. Part 3: pregn-4-eno-[3,2-c]pyrazole fused A ring modified steroids as selective glucocorticoid receptor modulators (dissociated steroids).

The introduction of A ring pyrazole modification to the hydrocortisone C-21 heteroaryl thioethers generated compounds with excellent transrepression potency (IL-8 inhibition) compared to their hydrocortisone analogs. However, the transcriptional transactivation activity of these compounds were considerably higher than the corresponding hydrocortisone analogs. Among all the compounds evaluated, a quinoxaline thioether modification demonstrated the best overall in vitro separation.

Steroidal C-21 mercapto derivatives as dissociated steroids: discovery of an inhaled dissociated steroid.

A series of C-21 mercapto derivatives of hydrocortisone have been synthesized and evaluated in cell based transrepression and transactivation assays. The benzothiazole derivative, compound 6 not only showed a dissociated profile in vitro functional assays but also a pharmacological profile in a Brown-Norway rat therapeutic index model of asthma that dissociated side effects (thymolysis) while maintaining efficacy against pulmonary inflammation and lung function.

Discovery of MK-8318, a Potent and Selective CRTh2 Receptor Antagonist for the Treatment of Asthma.

A novel series of tricyclic tetrahydroquinolines were identified as potent and selective CRTh2 receptor antagonists. The agonism and antagonism switch was achieved through structure-based drug design (SBDD) using a CRTh2 receptor homologue model. The challenge of very low exposures in pharmacokinetic studies was overcome by exhaustive medicinal chemistry lead optimization through focused SAR studies on the tricyclic core. Further optimization resulted in the identification of the preclinical candidate 4-(cyclopropyl((3aS,9R,9aR)-7-fluoro-4-(4-(trifluoromethoxy)benzoyl)-2,3,3a,4,9,9a-hexahydro-1H-cyclopenta[b]quinolin-9-yl)amino)-4-oxobutanoic acid (15c, MK-8318) with potent and selective CRTh2 antagonist activity and a favorable PK profile suitable for once daily oral dosing for potential treatment of asthma.

Drug Safety and the Cost of Monitoring: The Role of REMS in Risk Management.

BACKGROUND: The mission of the US Food and Drug Administration (FDA) can be viewed as a pendulum that swings between protecting public health and patient safety and promoting the public health through the drug review and approval process. Two decades of legislation have by and large provided the FDA with additional resources under the successive reauthorizations of the Prescription Drug User Fee Acts (PDUFA) to provide a necessary infusion of funds to hire medical experts, scientists, and epidemiologists, among other disciplines, to expedite review of new drug and biologic applications. However, a renewed attention to potential adverse drug experiences, culminating in the Vioxx withdrawal, has resulted in the passage of the Food and Drug Administration Amendments Act of 2007 (FDAAA). Under this act, the FDA was authorized to impose postapproval requirements on the biopharmaceutical industry through the imposition of risk evaluation and mitigation strategies (REMS) and postmarketing trial (PMT) requirements to improve drug safety. Despite the extensive dialogue between stakeholders and lawmakers in the development of the FDAAA, there remains some uncertainty as to the exact impact of REMS on not only operational costs for both industry and health care professionals but also product sales and prescribing habits in the 5 years since its implementation. METHODS: Recognizing that in the past 2 years, the use of REMS has shifted markedly, we sought to provide greater clarity on the duration of REMS requirements and impact of REMS on drug sales. RESULTS: While in absolute terms, the use of REMS may be declining, the REMS experience has provided an important, perhaps even critical, step in the development of current risk management strategies aimed at improving patient safety.