Design and synthesis of potent RSK inhibitors

Utilizing the already described 3,4-bi-aryl pyridine series as a starting point, incorporation of a second ring system with a hydrogen bond donor and additional hydrophobic contacts yielded the azaindole series which exhibited potent, picomolar RSK2 inhibition and the most potent in vitro target modulation seen thus far for a RSK inhibitor. In the context of the more potent core, several changes at the phenol moiety were assessed to potentially find a tool molecule appropriate for in vivo evaluation.

Optimization of 3-Pyrimidin-4-yl-oxazolidin-2-ones as Orally Bioavailable and Brain Penetrant Mutant IDH1 Inhibitors

Mutant isocitrate dehydrogenase 1 (IDH1) is an attractive therapeutic target for the treatment of various cancers such as AML, glioma, and glioblastoma. We have evaluated 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors that bind to an allosteric, induced pocket of IDH1^R132H. This Letter describes SAR exploration focused on improving both the in vitro and in vivo metabolic stability of the compounds, leading to the identification of 19 as a potent and selective mutant IDH1 inhibitor that has demonstrated brain penetration and excellent oral bioavailability in rodents. In a preclinical patient-derived IDH1 mutant xenograft tumor model study, 19 efficiently inhibited the production of the biomarker 2-HG.

Discovery and Evaluation of Clinical Candidate IDH305, a Brain Penetrant Mutant IDH1 Inhibitor

Inhibition of mutant IDH1 is being evaluated clinically as a promising treatment option for various cancers with hotspot mutation at Arg¹³². Having identified an allosteric, induced pocket of IDH1^R132H, we have explored 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors for in vivo modulation of 2-HG production and potential brain penetration. We report here optimization efforts toward the identification of clinical candidate IDH305 (13), a potent and selective mutant IDH1 inhibitor that has demonstrated brain exposure in rodents. Preclinical characterization of this compound exhibited in vivo correlation of 2-HG reduction and efficacy in a patient-derived IDH1 mutant xenograft tumor model. IDH305 (13) has progressed into human clinical trials for the treatment of cancers with IDH1 mutation.

Discovery of RAF265: A Potent mut-B-RAF Inhibitor for the Treatment of Metastatic Melanoma

Abrogation of errant signaling along the MAPK pathway through the inhibition of B-RAF kinase is a validated approach for the treatment of pathway-dependent cancers. We report the development of imidazo-benzimidazoles as potent B-RAF inhibitors. Robust in vivo efficacy coupled with correlating pharmacokinetic/pharmacodynamic (PKPD) and PD-efficacy relationships led to the identification of RAF265, 1, which has advanced into clinical trials.

Discovery of Potent and Selective RSK Inhibitors as Biological Probes

While the p90 ribosomal S6 kinase (RSK) family has been implicated in multiple tumor cell functions, the full understanding of this kinase family has been restricted by the lack of highly selective inhibitors. A bis-phenol pyrazole was identified from high-throughput screening as an inhibitor of the N-terminal kinase of RSK2. Structure-based drug design using crystallography, conformational analysis, and scaffold morphing resulted in highly optimized difluorophenol pyridine inhibitors of the RSK kinase family as demonstrated cellularly by the inhibition of YB1 phosphorylation. These compounds provide for the first time in vitro tools with an improved selectivity and potency profile to examine the importance of RSK signaling in cancer cells and to fully evaluate RSK as a therapeutic target.

Correction to Design and Synthesis of Orally Bioavailable Benzimidazole Reverse Amides as Pan RAF Kinase Inhibitors

[This corrects the article DOI: 10.1021/ml5002272.].

Design, structure-activity relationship, and in vivo characterization of the development candidate NVP-HSP990

Utilizing structure-based drug design, a novel dihydropyridopyrimidinone series which exhibited potent Hsp90 inhibition, good pharmacokinetics upon oral administration, and an excellent pharmacokinetic/pharmacodynamic relationship in vivo was developed from a commercial hit. The exploration of this series led to the selection of NVP-HSP990 as a development candidate.

Design and Synthesis of Orally Bioavailable Benzimidazole Reverse Amides as Pan RAF Kinase Inhibitors

Benzimidazole reverse amides were designed and synthesized as Pan RAF kinase inhibitors. Investigation of the structure-activity relationship of the compounds revealed that they were potent in vitro and exhibited desirable in vivo properties.

2-Amino-7-substituted benzoxazole analogs as potent RSK2 inhibitors

2-Amino-7-substituted benzoxazole analogs were identified by HTS as inhibitors of RSK2. Molecular modeling and medicinal chemistry techniques were employed to explore the SAR for this series with a focus of improving in vitro and target modulation potency and physicochemical properties.

Performance of the density matrix functional theory in the quantum theory of atoms in molecules

The generalization to arbitrary molecular geometries of the energetic partitioning provided by the atomic virial theorem of the quantum theory of atoms in molecules (QTAIM) leads to an exact and chemically intuitive energy partitioning scheme, the interacting quantum atoms (IQA) approach, that depends on the availability of second-order reduced density matrices (2-RDMs). This work explores the performance of this approach in particular and of the QTAIM in general with approximate 2-RDMs obtained from the density matrix functional theory (DMFT), which rests on the natural expansion (natural orbitals and their corresponding occupation numbers) of the first-order reduced density matrix (1-RDM). A number of these functionals have been implemented in the promolden code and used to perform QTAIM and IQA analyses on several representative molecules and model chemical reactions. Total energies, covalent intra- and interbasin exchange-correlation interactions, as well as localization and delocalization indices have been determined with these functionals from 1-RDMs obtained at different levels of theory. Results are compared to the values computed from the exact 2-RDMs, whenever possible.

Origins of regioselectivity in the reactions of alpha-lactams with nucleophiles. Two distinct acid-catalyzed pathways involving O- and N-protonation

Sterically stabilized alpha-lactams react by two distinct acid-catalyzed pathways. Protonation on oxygen results in nucleophilic attack at the acyl carbon and gives C-2 products. Protonation on nitrogen leads to nucleophilic attack at the C-3 carbon and yields C-3 products. The mechanism thus developed is very useful for understanding the changes in rates and product distributions in the reactions of sterically stabilized alpha-lactams with nucleophiles. It can also be extrapolated to other alpha-lactams so that a more coherent picture of alpha-lactam reactivity can be developed.

Randomized cross-over study of a 21-day versus a 28-day hormone replacement therapy (HRT)

OBJECTIVE

To compare the occurrence of climacteric symptoms at two points in the cycle, identified as minE (phase of minimum estrogen effect) and MaxP (phase of maximum progesterone effect).

METHODS

Prospective randomized cross-over study in postmenopausal women currently on HRT comparing two opposed, sequential formulations: a regimen of 21 tablets containing estradiol valerate (EV) opposed with cyproterone acetate (CPA) in the last 10 tablets, versus a regimen of 28 tablets of conjugated equine estrogens (CEE), the last 12 tablets of which were taken together with norgestrel (NG).

OUTCOME MEASURES

Incidence of 24 climacteric complaints assessed at the specified days of the cycle corresponding to minE (day 6 or 7) and MaxP (day 27 or 28)

RESULTS

Contrary to the hypothesis that estrogen-dependent symptoms will recur at minE of the 21-day regimen, no significant differences were noted with the regimen containing 28 days of CEE, which served as the control. There were more complaints with the CEE+NG formulation at both minE and MaxP. Of the 38 patients, 63% preferred the EV+CPA regimen, 18.4% the CEE+NG regimen and 18.4% rated both preparations as equal.

CONCLUSIONS

The 7-day pause in the 21-day formulation containing EV+CPA did not affect efficacy; it was as effective in relieving climacteric symptoms as the regimen containing 28 days of estrogen. Based on the frequency of complaints both at minE and MaxP, the EV+CPA formulation induced a more acceptable symptom and mood profile.

Endocrine effects in Asian postmenopausal women, treated with SH D 461 M and Prempak-C

We reported the results of a randomized cross-over study comparing SH D 461 M (Climen) and Prempak-C in 38 postmenopausal women who were established users of hormone replacement therapy (HRT). Climen contains 11 tablets of 2 mg estradiol valerate (EV), and 10 tablets with 2 mg EV plus 1 mg of cyproterone acetate. Prempak-C, on the other hand, is a regimen consisting of 28 tablets of 0.625 mg conjugated equine estrogens (CEE); the last 12 tablets are taken together with 0.15 mg of norgestrel (NG) tablets. Patients in Sequence I started with Climen for 6 months and then crossed-over to Prempak-C, for the next 6 months. Patients in Sequence II followed the reverse order. Following Climen treatment, significantly higher levels (P < 0.05, t-test) of sex hormone binding globulin (SHBG) and estradiol, when compared to Prempak-C treated subjects, were noted. No significant differences in follicle stimulating hormone (FSH), corticosteroid binding globulin (CBG), renin angiotensinogen, angiotensin-I and aldosterone levels between the two treatment regimens were noted. While both regimens were effective in reducing menopausal symptoms, none of the regimens could eliminate all symptoms completely. Treatment with Climen appeared to result in less frequent occurrences of some symptoms. During periods of no estrogen (only true for Climen) as well as periods of maximum P and E, subjects on Climen had significantly lower incidence of some of the symptoms (backache, lack of concentration, lethargy and swelling) when compared to those on Prempak-C.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine effects in Asian postmenopausal women treated with SH D 461 M and Prempak-C

We reported the results of a randomized cross-over study comparing SH D 461 M (Climen) and Prempak-C in 38 postmenopausal women who were established users of hormone replacement therapy (HRT). Climen contains 11 tablets of 2 mg estradiol valerate (EV), and 10 tablets with 2 mg EV plus 1 mg of cyproterone acetate. Prempak-C, on the other hand, is a regime consisting of 28 tablets of 0.625 mg conjugated equine estrogens (CEE); the last 12 tablets are taken together with 0.15 mg of norgestrel (NG) tablets. Patients in Sequence I started with Climen for 6 months and then crossed-over to Prempak-C, for the next 6 months; patients in Sequence II, followed the reverse order. Following Climen treatment, significantly higher levels (P < 0.05, t-test) of sex hormone binding globulin (SHBG) and estradiol, when compared to Prempak-C treated subjects, were noted. No significant differences in follicle stimulating hormone (FSH), corticosteroid binding globulin (CBG), renin, angiotensinogen, angiotensin-I and aldosterone levels between the two treatment regimes were noted. While both regimes were effective in reducing menopausal symptoms, none of the regimes could eliminate all symptoms completely. Treatment with Climen appeared to result in less frequent occurrences of some symptoms. During periods of no estrogen (only true for Climen) as well as periods of maximum progestagen and estrogen (P and E), subjects on Climen had significantly lower incidence of some of the symptoms (backache, lack of concentration, lethargy and swelling) when compared to those on Prempak-C.(ABSTRACT TRUNCATED AT 250 WORDS)