Balancing potency and basicity by incorporating fluoropyridine moieties: Discovery of a 1-amino-3,4-dihydro-2,6-naphthyridine BACE1 inhibitor that affords robust and sustained central Aß reduction.

ß-Site amyloid precursor protein cleaving enzyme 1 (BACE1) has been pursued as a prime target for the treatment of Alzheimer's disease (AD). In this report, we describe the discovery of BACE1 inhibitors with a 1-amino-3,4-dihydro-2,6-naphthyridine scaffold. Leveraging known inhibitors 2a and 2b, we designed the naphthyridine-based compounds by removing a structurally labile moiety and incorporating pyridine rings, which showed increased biochemical and cellular potency, along with reduced basicity on the amidine moiety. Introduction of a fluorine atom on the pyridine culminated in compound 11 which had improved cellular activity as well as further reduced basicity and demonstrated a robust and sustained cerebrospinal fluid (CSF) Aß reduction in dog. The crystal structure of compound 11 bound to BACE1 confirmed van der Waals interactions between the fluorine on the pyridine and Tyr71 in the flap.

Discovery of a potent orally bioavailable retinoic acid receptor-related orphan receptor-gamma-t (RORγt) inhibitor, S18-000003.

The retinoic acid receptor-related orphan receptor-gamma-t (RORγt) is the master transcription factor responsible for regulating the development and function of T-helper 17 (Th17) cells, which are related to the pathology of several autoimmune disorders. Therefore, RORγt is an attractive drug target for such Th17-mediated autoimmune diseases. A structure-activity relationship (SAR) study of lead compound 1 yielded a novel series of RORγt inhibitors, represented by compound 6. Detailed SAR optimization, informed by X-ray cocrystal structure analysis, led to the discovery of a potent orally bioavailable RORγt inhibitor 25, which inhibited IL-17 production in the skin of IL-23-treated mice by oral administration.

Benefit of FOLFOX to unresectable liver metastases secondary from colorectal carcinoma in an oncologic emergency.

Liver metastasis is an important prognostic factor in colorectal cancer. The efficacy of resection of metastatic lesions in liver metastasis of colorectal cancer is also widely recognized. However, studies on treatment methods of unresectable cases have not been sufficient and obtaining complete remission (CR) for liver metastasis is rare with chemotherapy. Selection of reliable chemotherapy for unresectable liver metastasis is an urgent necessity. The usefulness of oxaliplatin, 5-flurouracil and leucovorin combination therapy (FOLFOX) has recently been reported, but CR of liver metastasis is rare. The current status and new therapeutic significance of FOLFOX therapy are discussed based on the literature of colorectal cancer chemotherapy to date, and the clinical experience in which we obtained CR for liver metastasis is reported. The patient had stage IV rectal cancer, perforative peritonitis, pelvic abscess and simultaneous multiple liver metastasis. The patient underwent an emergency operation using the Hartmann's procedure. Liver metastasis is considered to be a prognostic factor and FOLFOX was selected as the postoperative chemotherapy, CR of the liver metastasis was obtained. FOLFOX was suggested to have new clinical significance in oncologic emergencies against unresectable liver metastasis in colorectal cancer and should serve as adjuvant chemotherapy that will contribute to improvement of treatment results.