Discovery and preclinical profile of YK-2168, a differentiated selective CDK9 inhibitor in clinical development.

Emerging clinical evidence indicates that selective CDK9 inhibition may provide clinical benefits in the management of certain cancers. Many CDK9 selective inhibitors have entered clinical developments, and are being investigated. No clear winner has emerged because of unforeseen toxicity often observed in clinic with these agents. Therefore, a novel agent with differentiated profiles is still desirable. Herein, we report our design, syntheses of a novel azaindole series of selective CDK9 inhibitors. SAR studies led to a preclinical candidate YK-2168. YK2168 exhibited improved CDK9 selectivity over AZD4573 and BAY1251152; also showed differentiated intravenous PK profile and remarkable solid tumor efficacy in a mouse gastric cancer SNU16 CDX model in preclinical studies. YK-2168 is currently in clinical development in China (CTR20212900).

Randomly Methylated ß-Cyclodextrin Inclusion Complex with Ketoconazole: Preparation, Characterization, and Improvement of Pharmacological Profiles.

As a powerful imidazole antifungal drug, ketoconazole's low solubility (0.017 mg/mL), together with its odor and irritation, limited its clinical applications. The inclusion complex of ketoconazole with randomly methylated ß-cyclodextrin was prepared by using an aqueous solution method after cyclodextrin selection through phase solubility studies, complexation methods, and condition selection through single factor and orthogonal strategies. The complex was confirmed by FTIR (Fourier-transform infrared spectroscopy), DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), SEM (scanning electron microscope images), and NMR (Nuclear magnetic resonance) studies. Through complexation, the water solubility of ketoconazole in the complex was increased 17,000 times compared with that of ketoconazole alone, which is the best result so far for the ketoconazole water solubility study. In in vitro pharmacokinetic studies, ketoconazole in the complex can be 100% released in 75 min, and in in vivo pharmacokinetic studies in dogs, through the complexation, the Cmax was increased from 7.56 µg/mL to 13.58 µg/mL, and the AUC0~72 was increased from 22.69 µgh/mL to 50.19 µgh/mL, indicating that this ketoconazole complex can be used as a more efficient potential new anti-fungal drug.

Preparation and evaluation of fenbendazole methyl-ß-cyclodextrin inclusion complexes.

As an orally effective benzimidazole anthelmintic agent, fenbendazole was not only widely used in agriculture and animal husbandry to prevent and treat parasites, but also shows anti-cancer effects against several types of cancer, exhibits anti-cancer effects in paclitaxel and doxorubicin-resistant cancer cells. However, fenbendazole's poor in water solubility (0.3 µg/mL), limits its clinical applications. Even great efforts were made toward increasing its water solubility, the results were not significant to reach anti-cancer drug delivery requirement (5-10 mg/mL). Through single factor and orthogonal strategy, many complex conditions were designed and used to prepare the complexes, the inclusion complex with methyl-ß-cyclodextrin with 29.2 % of inclusion rate and 89.5% of inclusion yield can increase drug's water solubility to 20.21 mg/mL, which is the best result so far. Its structure was confirmed by differential scanning calorimetry, scanning electron microscopic image, 1D and 2D NMR spectra in D2O. In its in vitro pharmacokinetic study, fenbendazole was 75% released in 15 min., in its in vivo pharmacokinetic study, the bio-availabilities of fenbendazole, its major metabolic anthelmintic agent oxfendazole and its minor metabolic anthelmintic agent oxfendazole were increased to 138%, 149% and 169% respectively, which would allow for fewer drug doses to achieve the same therapeutic effect and suggest that the complex can be used as a potential anticancer agent.

Discovery and preclinical evaluations of TQB3616, a novel CDK4-biased inhibitor.

Among small-molecule CDK4/6 inhibitors (palbociclib, ribociclib, and abemaciclib) approved for metastatic breast cancers, abemaciclib has a more tolerable adverse effects in clinic. This is attributable to preferential inhibition of CDK4 over CDK6. In our search for a biased CDK4 inhibitor, we discovered a series of pyrimidine-indazole inhibitors. SAR studies led us to TQB3616 as a preferential CDK4 inhibitor. TQB3616 exhibited improvements in both enzymatic and cellular proliferation inhibitory potency when tested side-by-side with the FDA approved palbociclib and abemaciclib. TQB3616 also possessed favorable PK profile in multiple species. These differentiated properties, together with excellent GLP safety profile warranted TQB3616 moving to clinic. TQB3616 entered into clinical development in 2019 and currently in phase III clinical trials (NCT05375461, NCT05365178).

The Use of Cyclodextrin Inclusion Complexes to Increase the Solubility and Pharmacokinetic Profile of Albendazole.

Albendazole is the preferred deworming drug and has strong insecticidal effects on human and animal helminth parasites, showing remarkable activity against hepatocellular carcinoma and colorectal cancer cells. However, it is classified as being in class II in the Biopharmaceutics Classification System due to its poor water solubility (0.2 mg/L) and high permeability, which make the clinical application of albendazole impractical. Through complexation with methyl-ß-cyclodextrin, as the best result so far, albendazole's water solubility was increased by 150,000 times, and albendazole could be 90% released during the first 10 min. In an in vivo pharmacokinetic study, the Cmax and Tmax of the active metabolized sulfoxide were changed from 2.81 µg/mL at 3 h to 10.2 µg/mL at 6 h and the AUC0-48 was increased from 50.72 h⁎µg/mL to 119.95 h⁎µg/mL, indicating that the inclusion complex obtained can be used as a new oral therapeutic anti-anthelmintic and anti-tumor agent formulation.

Solubility and Pharmacokinetic Profile Improvement of Griseofulvin through Supercritical Carbon Dioxide-Assisted Complexation with HP-γ-Cyclodextrin.

Since griseofulvin was marketed as a non-polyene antifungal antibiotic drug in 1958, its poor water solubility has been an issue for its wide applications, and over the last sixty years, many attempts have been made to increase its water solubility; however, a significant result has yet to be achieved. Through supercritical carbon dioxide-assisted cyclodextrin complexation with the addition of a trace amount of water-soluble polymer surfactant, the griseofulvin inclusion complex with HP-γ-cyclodextrin was prepared and confirmed. The 1:2 ratio of griseofulvin and HP-γ-cyclodextrin in the complex was determined based on its NMR study. After complexation with HP-γ-cyclodextrin, griseofulvin's water solubility was increased 477 times compared with that of griseofulvin alone, which is the best result thus far. The complex showed 90% of griseofulvin release in vitro in 10 min, in an in vivo dog pharmacokinetic study; the Cmax was increased from 0.52 µg/mL to 0.72 µg/mL, AUC0-12 was increased from 1.55 µg·h/mL to 2.75 µg·h/mL, the clearance was changed from 51.78 L/kg/h to 24.16 L/kg/h, and the half-life time was changed from 0.81 h to 1.56 h, indicating the obtained griseofulvin complex can be a more effective drug than griseofulvin alone.

Improvement of solubility and pharmacokinetic profile of hepatoprotector icariin through complexation with HP-γ-cyclodextrin.

Icariin as a hepatoprotector from Herba epimedii can expand the cardiovascular and cerebral blood vessels, promote hematopoietic functions, enhance the immune system and show anti-liver tumor activities. However, its low solubility (0.02 mg/mL) limits its clinical applications as food and medical supplements. Through complexation with HP-γ-cyclodextrin by using a trace amount of water-soluble polymer, the water solubility of icariin was increased by 654 times, which is the best result to date for the water solubility study of icariin. In an in vitro pharmacokinetic study, the complexation increased the dissolution rate of icariin by 80 times, and the icariin complex can be 100% released in the first few minutes. Through complexation, in an in vivo dog pharmacokinetic study, the C max of icariin was increased about 5 times, the AUC0-120 was increased about 20 times and the clearance of icariin was changed from 11.17 L/h/kg to 0.65 L/h/kg. The half-life time was changed from 0.68 h to 6.38 h and the relative bioavailability was increased by nearly 20 times, indicating that less drug is needed for the same therapeutic effect by using the icariin complex, and the complex can be used as a potential potent hepatoprotector or anti-liver cancer drug.

Tilmicosin/γ-Cyclodextrin complexation through supercritical carbon dioxide assistance and its pharmacokinetic and antibacterial study.

Tilmicosin, as an effective broad-spectrum antibacterial drug, has incomplete absorption and low bioavailability due to its low water solubility, which limits its veterinary clinical applications. As a non-polymeric drug carrier, γ-cyclodextrin was complexed with tilmicosin through supercritical carbon dioxide assistance for the first time, and confirmed by FTIR, X-ray diffraction, proton NMR and scanning electron microscopy. The water solubility of tilmicosin was increased 57-fold through complexation with γ-cyclodextrin, and the release and bioavailability of tilmicosin in the complex were significantly improved. The tilmicosin in complex showed better anti-Streptococcus agalactiae activity than that of tilmicosin alone in MIC, MBC and drug susceptibility studies.

Discovery and preclinical evaluations of GST-HG131, a novel HBV antigen inhibitor for the treatment of chronic hepatitis B infection.

Chronic hepatitis B (CHB) remains a significant health challenge worldwide. The current treatments for CHB achieve less than 10% cure rates, majority of the patients are on therapy for life. Therefore, cure of CHB is a high unmet medical need. HBV surface antigen (HBsAg) loss and seroconversion are considered as the key for the cure. RG7834 is a novel, orally bioavailable small molecule reported to reduce HBV antigens. Based on RG7834 chemistry, we designed and discovered a series of dihydrobenzopyridooxazepine (DBP) series of HBV antigen inhibitors. Extensive SAR studies led us to GST-HG131 with excellent reduction of HBV antigens (both HBsAg and HBeAg) in vitro and in vivo. GST-HG131 improved safety in rat toxicology studies over RG7834. The promising inhibitory activity, together with animal safety enhancement, merited GST-HG131 progressed into clinical development in 2020 (NCT04499443).

Discovery and preclinical evaluations of JBD0131, a novel nitrodihydro-imidazooxazole anti-tuberculosis agent.

Multidrug-resistant pulmonary tuberculosis (MDR-TB) is a major health problem worldwide. The treatment for MDR-TB requires medications for a long duration (up to 20-24 months) with second-line drugs resulting in unfavorable outcomes. Nitroimidazoles are promising antimycobacterial agents known to inhibit both aerobic and anaerobic mycobacterial activity. Delamanid and pretomanid are two nitroimidazoles approved by the regulatory agencies for MDR-TB treatment. However, both agents possess unsatisfactory absorption and QTc prolongation. In our search for a safer nitroimidazole, we discovered JBD0131 (2). It exhibited excellent anti-mycobacterial activity against M. tuberculosis H37Rv in vitro and in vivo, improved PK and absorption, reduced QT prolongation potential of delamanid. JBD0131 is currently in clinical development in China for pulmonary tuberculosis (CTR20202308).

Discovery and preclinical profile of sudapyridine (WX-081), a novel anti-tuberculosis agent.

Multidrug resistant tuberculosis (MDR-TB) remains a major human health challenge. Bedaquiline was approved in 2012 by the US FDA, and listed by WHO as a treatment for multidrug-resistant tuberculosis (MDR-TB) in 2018. However, the side effects of bedaquiline including the risk of unexplained mortality, QTc prolongation and hepatotoxicity limit its wide clinical use. Based on bedaquiline, we describe herein discovery and development of a novel diarylpyridine series, which led to identification of WX-081 (sudapyridine, 21l). It displayed excellent anti-mycobacterial activity against M. tuberculosis H37Rv in vitro and in vivo and low cytotoxicity; additionally WX-081 had excellent pharmacokinetic parameters in animals, better lung exposure and lower QTc prolongation potential compared to bedaquiline. WX-081 is currently under clinical phase II development (NCT04608955).

Safety, Tolerability, and Pharmacokinetics of the Novel Hepatitis B Virus Expression Inhibitor GST-HG131 in Healthy Chinese Subjects: a First-in-Human Single- and Multiple-Dose Escalation Trial.

GST-HG131, a novel dihydroquinolizinone (DHQ) compound, has been shown to reduce circulating levels of HBsAg in animals. This first-in-human trial evaluated the safety, tolerability, and pharmacokinetic profile of GST-HG131 in healthy Chinese subjects. This was a double-blind, randomized, placebo-controlled phase Ia clinical trial that was conducted in two parts. Part A was a single-ascending-dose (SAD; GST-HG131 10 30, 60, 100, 150, 200, 250 or 300 mg or placebo) study, which also assessed the food effect of GST-HG131 100 mg. Part B was a multiple-ascending-dose (MAD; GST-HG131 30, 60 or 100 mg or placebo BID) study. Tolerability assessments included adverse events, vital signs, 12-lead electrocardiogram, physical examination, and clinical laboratory tests. PK analyses were conducted in blood, urine, and fecal samples. Single doses of GST-HG131 ≤ 300 mg and multiple doses of GST-HG131 ≤ 60 mg were generally safe and well tolerated; however, multiple dosing was stopped at GST-HG131 100 mg, as pre-defined stopping rules specified in the protocol were met (Grade II drug related AEs of nausea and dizziness in >50% of subjects). In the SAD study, median tmax of GST-HG131 was 1-6 h, and t1/2 ranged from 3.88 h to 14.3 h. PK parameters were proportional to dose. Exposure was reduced after food intake. In the MAD study, steady-state was attained on day 4, and there was no apparent plasma accumulation of GST-HG131 on day 7 (Racc < 1.5). In conclusion, GST-HG131 exhibited an acceptable safety profile in healthy subjects at single doses ranging from 10-300 mg and multiple doses (BID) ranging from 30-60 mg, and the MAD doses (30 mg and 60 mg BID) that potentially meet the therapeutic AUC requirements. These findings imply GST-HG131 has potential as a therapeutic option for CHB infection. (This study has been registered at ClinicalTrials.gov under identifier NCT04499443.).

Discovery and preclinical profile of LX-039, a novel indole-based oral selective estrogen receptor degrader (SERD).

We previously described the discovery of a novel indole series compounds as oral SERD for ER positive breast cancer treatment. Further SAR exploration focusing on substitutions on indole moiety of compound 12 led to the discovery of a clinical candidate LX-039. We report herein its profound anti-tumor activity, desirable ER antagonistic characteristics combined with favorable pharmacokinetic and preliminary safety properties. LX-039 is currently in clinical trial (NCT04097756).

Discovery and preclinical evaluations of WX-0593, a novel ALK inhibitor targeting crizotinib-resistant mutations.

ALK gene rearrangements are oncogenic drivers in approximately 5% of NSCLC. Crizotinib, a first generation ALK inhibitor, is widely prescribed for ALK-positive NSCLC in clinic. Resistance to crizotinib and other ALK inhibitors has been problematic. Addressing resistance, here we describe discovery and development of a novel, proprietary spirocyclic diamine-substituted aryl phosphine oxide series of inhibitors, which led to the identification of WX-0593 (16a) as a potent ALK inhibitor. WX-0593 inhibited the activity of both wild type and resistant mutants of ALK in vitro, showed strong antitumor activity in a crizotinib-resistant mouse PDX model. WX-0593 is currently under development in phase II/III clinical trials.

Design, Synthesis, and Characterization of TNP-2198, a Dual-Targeted Rifamycin-Nitroimidazole Conjugate with Potent Activity against Microaerophilic and Anaerobic Bacterial Pathogens.

TNP-2198, a stable conjugate of a rifamycin pharmacophore and a nitroimidazole pharmacophore, has been designed, synthesized, and evaluated as a novel dual-targeted antibacterial agent for the treatment of microaerophilic and anaerobic bacterial infections. TNP-2198 exhibits greater activity than a 1:1 molar mixture of the parent drugs and exhibits activity against strains resistant to both rifamycins and nitroimidazoles. A crystal structure of TNP-2198 bound to a Mycobacterium tuberculosis RNA polymerase transcription initiation complex reveals that the rifamycin portion of TNP-2198 binds to the rifamycin binding site on RNAP and the nitroimidazole portion of TNP-2198 interacts directly with the DNA template-strand in the RNAP active-center cleft, forming a hydrogen bond with a base of the DNA template strand. TNP-2198 is currently in Phase 2 clinical development for the treatment of Helicobacter pylori infection, Clostridioides difficile infection, and bacterial vaginosis.

Design, syntheses and evaluations of novel indole derivatives as orally selective estrogen receptor degraders (SERD).

Most estrogen receptor positive (ER +) breast cancers depend on ER signaling pathway to develop. Clinical application of SERD fulvestrant effectively degraded ER, blocked its function and prolonged progression free survival of ER + breast cancer patients. However, current SERD suffers from limited bioavailability, therefore is given as intramuscular (IM) injection. In this paper, we report herein a novel indole series compounds with nanomolar range ER degradation potencies and oral systemic exposures. Selected compounds suppressed tumor growth in vivo in ER + MCF7 breast cancer CDX model via p.o. administration. All those data supported further optimizations of this analog to develop preclinical candidate as oral SERD for ER + breast cancer's treatment.

Therapeutic Effect and Mechanisms of the Novel Monosulfactam 0073.

This study aimed to evaluate the antimicrobial activity of the novel monosulfactam 0073 against multidrug-resistant Gram-negative bacteria in vitro and in vivo and to characterize the mechanisms underlying 0073 activity. The in vitro activities of 0073, aztreonam, and the combination with avibactam were assessed by MIC and time-kill assays. The safety of 0073 was evaluated using 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and acute toxicity assays. Murine thigh infection and pneumonia models were employed to define in vivo efficacy. A penicillin-binding protein (PBP) competition assay and confocal microscopy were conducted. The inhibitory action of 0073 against ß-lactamases was evaluated by the half-maximal inhibitory concentration (IC50), and resistance development was evaluated via serial passage. The monosulfactam 0073 showed promising antimicrobial activity against Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii isolates producing metallo-ß-lactamases (MBLs) and serine ß-lactamases. In preliminary experiments, compound 0073 exhibited safety both in vitro and in vivo In the murine thigh infection model and the pneumonia models in which infection was induced by P. aeruginosa and Klebsiella pneumoniae, 0073 significantly reduced the bacterial burden. Compound 0073 targeted several PBPs and exerted inhibitory effects against some serine ß-lactamases. Finally, 0073 showed a reduced propensity for resistance selection compared with that of aztreonam. The novel monosulfactam 0073 exhibited increased activity against ß-lactamase-producing Gram-negative organisms compared with the activity of aztreonam and showed good safety profiles both in vitro and in vivo The underlying mechanisms may be attributed to the affinity of 0073 for several PBPs and its inhibitory activity against some serine ß-lactamases. These data indicate that 0073 represents a potential treatment for infections caused by ß-lactamase-producing multidrug-resistant bacteria.

Synergistic Activity of Nitroimidazole-Oxazolidinone Conjugates against Anaerobic Bacteria.

The introductions of the bicyclic 4-nitroimidazole and the oxazolidinone classes of antimicrobial agents represented the most significant advancements in the infectious disease area during the past two decades. Pretomanid, a bicyclic 4-nitroimidazole, and linezolid, an oxazolidinone, are also part of a combination regimen approved recently by the US Food and Drug Administration for the treatment of pulmonary, extensively drug resistant (XDR), treatment-intolerant or nonresponsive multidrug-resistant (MDR) Mycobacterium tuberculosis (TB). To identify new antimicrobial agents with reduced propensity for the development of resistance, a series of dual-acting nitroimidazole-oxazolidinone conjugates were designed, synthesized and evaluated for their antimicrobial activity. Compounds in this conjugate series have shown synergistic activity against a panel of anaerobic bacteria, including those responsible for serious bacterial infections.

Discovery and evaluation of novel nitrodihydroimidazooxazoles as promising anti-tuberculosis agents.

New analogues of antitubercular drug Delamanid were prepared, seeking drug candidates with enhanced aqueous solubility and high efficacy. The strategy involved replacement of phenoxy linker proximal to the 2-nitroimidazooxazole of Delamanid by piperidine fused 5 or 6-membered ring heterocycles (ring A). The new compounds were all more hydrophilic than Delamanid, and several class of analogues showed remarkable activities against M. bovis. And among these series, the tetrahydro-naphthyridine-linked nitroimidazoles displayed excellent antimycobacterial activity against both replicating (MABA) and nonreplicating (LORA) M. tb H37Rv and low cytotoxicity. Compared to Delamanid, these new compounds (6, 7, 45) demonstrated dramatically improved physicochemical properties and are suitable for further in vitro and in vivo evaluation.

Synthesis of carbohydrate conjugated 6A,6D-bifunctionalized ß cyclodextrin derivatives as potential liver cancer drug carriers.

Galactosyl and lactosyl conjugated 6A,6D-bifunctionlized ß cyclodextrin derivatives were designed and synthesized as the potential liver cancer drug carriers through SN2 replacement and click reactions in order to increase liver cancer drug's targeting ability, solubility and stability. The synthetic methods and strategies to obtain the designed compounds were discussed.