Optimization of the phenylurea moiety in a phosphoinositide 3-kinase (PI3K) inhibitor to improve water solubility and the PK profile by introducing a solubilizing group and ortho substituents.

Phosphoinositide 3-kinase (PI3K) is a promising anti-cancer target, because various mutations and amplifications are observed in human tumors isolated from cancer patients. Our dihydropyrrolopyrimidine derivative with a phenylurea moiety showed strong PI3K enzyme inhibitory activity, but its pharmacokinetic property was poor because of lack of solubility. Herein, we report how we improved the solubility of our PI3K inhibitors by introducing a solubilizing group and ortho substituents to break molecular planarity.

Modification of a dihydropyrrolopyrimidine phosphoinositide 3-kinase (PI3K) inhibitor to improve oral bioavailability.

Phosphoinositide 3-kinase (PI3K) is activated in various human cancer cells and well known as a cancer therapy target. We previously reported a dihydropyrrolopyrimidine derivative as a highly potent PI3K inhibitor that has strong tumor growth inhibition in a xenograft model. In this report, we describe further optimization to improve its bioavailability.

Lead optimization of a dihydropyrrolopyrimidine inhibitor against phosphoinositide 3-kinase (PI3K) to improve the phenol glucuronic acid conjugation.

Our lead compound for a phosphoinositide 3-kinase (PI3K) inhibitor (1) was metabolically unstable because of rapid glucuronidation of the phenol moiety. Based on structure-activity relationship (SAR) information and a FlexSIS docking simulation score, aminopyrimidine was identified as a bioisostere of phenol. An X-ray structure study revealed a hydrogen bonding pattern of aminopyrimidine derivatives. Finally, aminopyrimidine derivatives 33 showed strong tumor growth inhibition against a KPL-4 breast cancer xenograft model in vivo.

Design and evaluation of azaindole-substituted N-hydroxypyridones as glyoxalase I inhibitors.

We conducted a high throughput screening for glyoxalase I (GLO1) inhibitors and identified 4,6-diphenyl-N-hydroxypyridone as a lead compound. Using a binding model of the lead and public X-ray coordinates of GLO1 enzymes complexed with glutathione analogues, we designed 4-(7-azaindole)-substituted 6-phenyl-N-hydroxypyridones. 7-Azaindole's 7-nitrogen was expected to interact with a water network, resulting in an interaction with the protein. We validated this inhibitor design by comparing its structure-activity relationship (SAR) with that of corresponding indole derivatives, by analyzing the binding mode with X-ray crystallography and by evaluating its thermodynamic binding parameters.

Design and synthesis of a highly selective, orally active and potent anaplastic lymphoma kinase inhibitor (CH5424802).

Anaplastic lymphoma kinase (ALK) receptor tyrosine kinase is considered an attractive therapeutic target for human cancers, especially non-small cell lung cancer (NSCLC). Our previous study revealed that 8,9-side-chains of 6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazole scaffold crucially affected kinase selectivity, cellular activity, and metabolic stability. In this work, we optimized the side-chains and identified highly selective, orally active and potent ALK inhibitor CH5424802 (18a) as the clinical candidate.

9-substituted 6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazoles as highly selective and potent anaplastic lymphoma kinase inhibitors.

9-Substituted 6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazoles were discovered as highly selective and potent anaplastic lymphoma kinase (ALK) inhibitors by structure-based drug design. The high target selectivity was achieved by introducing a substituent close to the E(0) region of the ATP binding site, which has a unique amino acid sequence. Among the identified inhibitors, compound 13d showed highly selective and potent inhibitory activity against ALK with an IC(50) value of 2.9 nM and strong antiproliferative activity against KARPAS-299 with an IC(50) value of 12.8 nM. The compound also displayed significant antitumor efficacy in an established ALK fusion gene-positive anaplastic large-cell lymphoma (ALCL) xenograft model in mice without body weight loss.

The selective class I PI3K inhibitor CH5132799 targets human cancers harboring oncogenic PIK3CA mutations.

PURPOSE: The phosphatidylinositol 3-kinase (PI3K) pathway plays a central role in cell proliferation and survival in human cancer. PIK3CA mutations, which are found in many cancer patients, activate the PI3K pathway, resulting in cancer development and progression. We previously identified CH5132799 as a novel PI3K inhibitor. Thus, this study aimed to clarify the biochemical and antitumor activity of CH5132799 and elucidate the correlation between CH5132799 response and genetic alterations in the PI3K pathway. EXPERIMENTAL DESIGN: Kinase inhibitory activity was profiled in cell-free assays. A large panel of human breast, ovarian, prostate, and endometrial cancer cell lines, as well as xenograft models, were used to evaluate the antitumor activity of CH5132799, followed by analysis for genetic alterations. Effects on Akt phosphorylation induced by mTORC1 inhibition were tested with CH5132799 and compared with mTORC1 and PI3K/mTOR inhibitors. RESULTS: CH5132799 selectively inhibited class I PI3Ks and PI3Kα mutants in in vitro kinase assays. Tumors harboring PIK3CA mutations were significantly sensitive to CH5132799 in vitro and were remarkably regressed by CH5132799 in in vivo mouse xenograft models. In combination with trastuzumab, tumors disappeared in the trastuzumab-insensitive breast cancer model with the PIK3CA mutation. Moreover, CH5132799 did not reverse a negative feedback loop of PI3K/Akt/mTOR signaling and induced regression against tumors regrown after long-term mTORC1 inhibitor treatment. CONCLUSIONS: CH5132799 is a selective class I PI3K inhibitor with potent antitumor activity against tumors harboring the PIK3CA mutations. Prediction of CH5132799 response on the basis of PIK3CA mutations could enable patient stratification in clinical settings.

Discovery and biological activity of a novel class I PI3K inhibitor, CH5132799.

Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase and a promising therapeutic target for cancer. Using structure-based drug design (SBDD), we have identified novel PI3K inhibitors with a dihydropyrrolopyrimidine skeleton. Metabolic stability of the first lead series was drastically improved by replacing phenol with aminopyrimidine moiety. CH5132799, a novel class I PI3K inhibitor, exhibited a strong inhibitory activity especially against PI3Kα (IC(50)=0.014 µM). In human tumor cell lines with PI3K pathway activation, CH5132799 showed potent antiproliferative activity. CH5132799 is orally available and showed significant antitumor activity in PI3K pathway-activated human cancer xenograft models in mice.

In vitro activity of isavuconazole against 140 reference fungal strains and 165 clinically isolated yeasts from Japan.

The in vitro susceptibilities of 140 laboratory reference strains of fungi, including type strains, and 165 clinical yeast isolates from Japan towards isavuconazole compared with fluconazole (FLC), itraconazole (ITC), voriconazole and amphotericin B were measured. Broth microdilution methods based on Clinical and Laboratory Standards Institute (CLSI) methods were used for yeasts, and RPMI-MOPS medium semi-solidified with 0.2% low-melting-point agarose based on CLSI guidelines was used for moulds. The range of isavuconazole minimum inhibitory concentrations (MICs) was 0.0004-0.21 mg/L for Candida albicans, 0.0036-0.4 mg/L for Candida glabrata, 0.023-0.058 mg/L for Candida krusei, 0.0026-0.032 mg/L for Cryptococcus neoformans, 0.1-0.39mg/L for Aspergillus fumigatus and 0.2-0.39 mg/L for Aspergillus terreus. Isavuconazole was as active as ITC against the dimorphic true pathogenic fungi, with a range of MICs from <0.0004 mg/L to 0.0063 mg/L for Blastomyces dermatitidis and Histoplasma capsulatum. It was also active against uncommon dematiaceous fungi such as Exophiala spp. and Phialophora spp. as well as against dermatophytic species. Isavuconazole showed very good in vitro antifungal activity with a broad spectrum, including against FLC-resistant Candida spp., Aspergillus spp. and uncommon opportunistic fungal species. This is the first report of the in vitro susceptibility of Japanese clinical yeast isolates to isavuconazole. No cross-resistance was found to isavuconazole amongst FLC-resistant strains.

A water soluble prodrug of a novel camptothecin analog is efficacious against breast cancer resistance protein-expressing tumor xenografts.

PURPOSE: Identification of a novel topoisomerase I inhibitor which shows superior efficacy and less individual variation than irinotecan hydrochloride (CPT-11). METHODS: A novel camptothecin analog that is effective against breast cancer resistance protein (BCRP)-positive cells was screened, and a water soluble prodrug was generated. Antitumor activity of the prodrug was examined in BCRP-positive and -negative xenografts both as a single agent and in combination with other anti-cancer drugs. RESULTS: A novel camptothecin analog, CH0793076, was discovered. Because CH0793076 was found to be highly lipophilic, a water soluble prodrug (TP300) was generated. TP300 is stable in an acidic solution but is rapidly converted to CH0793076 under physiological pH conditions such as in sera. This efficient prodrug activation would minimize interpatient differences in pharmacokinetic and toxicity profiles. Unlike CPT-11, TP300 does not exhibit cholinergic interaction or cause acute diarrhea at effective doses. In mouse xenograft models, TP300 showed antitumor activity against both BCRP-positive and -negative xenografts, whereas CPT-11 was less active against BCRP-positive xenografts. In addition, the effective dose range (MTD/ED(50)) for TP300 was wider than for CPT-11 and TP300 showed additive or synergistic antitumor effects in combination with other anti-cancer drugs such as capecitabine, oxaliplatin, cisplatin, bevacizumab and cetuximab. CONCLUSION: It is therefore expected that TP300 will provide an additional treatment option for patients who will undergo chemotherapy with camptothecins.

Synthesis and biological activities of a pH-dependently activated water-soluble prodrug of a novel hexacyclic camptothecin analog.

CH0793076 (1) is a novel hexacyclic camptothecin analog showing potent antitumor activity in various human caner xenograft models. To improve the water solubility of 1, water-soluble prodrugs were designed to generate an active drug 1 nonenzymatically, thus expected to show less interpatient PK variability than CPT-11. Among the prodrugs synthesized, 4c (TP300, hydrochloride) having a glycylsarcosyl ester at the C-20 position of 1 is highly water-soluble (>10mg/ml), stable below pH 4 and rapidly generates 1 at physiological pH in vitro. The rapid (ca. <1min) generation of 1 after incubation of TP300 with plasma (mouse, rat, dog and monkey) was also demonstrated. TP300 showed a broader antitumor spectrum and more potent antitumor activity than CPT-11 in various human cancer xenograft models.

Synthesis of new camptothecin analogs with improved antitumor activities.

Novel hexacyclic camptothecin analogs containing cyclic amidine, urea, or thiourea moiety were designed and synthesized based on the proposed 3D-structure of the topoisomerase I (Topo I)/DNA/camptothecin ternary complex. The analogs were prepared from 9-nitrocamptothecin via 7,9-diaminocamptothecin derivatives as a key intermediate. Among them, 7c exhibited in vivo antitumor activities superior to CPT-11 in human cancer xenograft models in mice at their maximum tolerated doses though its in vitro antiproliferative activity was comparable to SN-38 against corresponding cell lines.

Design, synthesis and antifungal activity of a novel water soluble prodrug of antifungal triazole.

A highly potent water soluble triazole antifungal prodrug, RO0098557 (1), has been identified from its parent, the novel antifungal agent RO0094815 (2). The prodrug includes a triazolium salt linked to an aminocarboxyl moiety, which undergoes enzymatic activation followed by spontaneous chemical degradation to release 2. Prodrug 1 showed high chemical stability and water solubility and exhibited strong antifungal activity against systemic candidiasis and aspergillosis as well as pulmonary aspergillosis in rats.

Synthesis of novel water soluble benzylazolium prodrugs of lipophilic azole antifungals.

Water soluble N-benzyltriazolium or N-benzylimidazolium salt type prodrugs of several highly lipophilic triazole or imidazole antifungals have been synthesized. They were designed to undergo an enzymatic activation followed by a self-cleavage to release a parent drug. The prodrugs such as 16 had enough chemical stability and water solubility for parenteral use and were rapidly and quantitatively converted to the active substance in human plasma.