Haisco Pharmaceutical Group Co., Ltd.

Crisugabalin, a novel third-generation ligand targeting the α2δ subunit of voltage-gated calcium channels, has been approved in China for the treatment of pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. Existing research suggests that ligands for the α2δ subunit of voltage-gated calcium channels may carry a risk of abuse. To evaluate the abuse potential of crisugabalin, five well-recognized animal models were utilized in these preclinical studies. Firstly, an intravenous self-administration paradigm was implemented in rats that were self-administering propofol to assess the reinforcing effects of crisugabalin. Secondly, a rat drug discrimination study was employed to determine the pharmacological similarity between crisugabalin and the training drug midazolam. Then, a conditioned place preference (CPP) paradigm in rats was utilized to evaluate the rewarding properties of crisugabalin. After that, a spontaneous withdrawal study was conducted in rats chronically treated with crisugabalin to examine the liability of developing physical dependence. Finally, a mouse pentylenetetrazol-induced convulsion model was used following chronic exposure to crisugabalin to assess its potential for physical dependence. The results indicated that crisugabalin showed no positive reinforcing effects and did not display midazolam-like discriminative stimulus effects. Moreover, crisugabalin did not induce significant CPP in rats and there was no risk of physical dependence in the pentylenetetrazol-induced convulsion model. In the rat spontaneous withdrawal study, crisugabalin demonstrated a very low level of physical dependence. These findings suggest that crisugabalin has minimal to no potential for abuse, thereby establishing itself as a safer option relative to pregabalin and mirogabalin.

HSK21542, a potent and peripherally-restricted kappa opioid receptor (KOR) agonist, is currently being developed to treat postoperative pain and pruritus. Given that conventional opioids (MOR agonists) are widely recognized for their toxicological impacts on the reproductive system and embryonic development, we evaluated the effects of HSK21542 accordingly. The results showed that HSK21542 did not influence male and female fertility or early embryonic development in rats. HSK21542 also did not show significant manifestations of pre- and post-natal development toxicity in rats. In the embryo-fetal developmental study, even though there was a 3.5 % increase in incidence of fetuses with incomplete ossification of thoracic vertebral centrum in the 4 mg/kg/day group, the plasma exposure of HSK21542 in rats at the no observed adverse effect level (NOAEL) was 82.3 times higher than that of human exposure at 1 μg/kg. On the other hand, exposure to HSK21542 during pregnancy in rabbits did not show any teratogenic risk, only causing a minor impact on bone ossification in fetuses. In conclusion, HSK21542 has a favorable safety profile with only minor effects on the embryo-fetal developmental outcomes.

Anrikefon (HSK21542), a potent and selective peripheral kappa opioid receptor (KOR) agonist developed by Haisco, effectively blocks pain and itch signals.

To develop a population pharmacokinetic (PK) model for anrikefon and conduct exposure-response (E-R) analysis for safety and efficacy in postoperative pain patients.

The Population PK analysis uses NONMEM software with data from six trials. E-R relationships were assessed using safety and efficacy data from three trials. Covariate screening and Bayesian post-hoc simulations identified relevant factors and compared exposure metrics. The fixed dosing regimen was evaluated by simulation. Safety and efficacy endpoints were evaluated using logistic regression and E_max models.

A three-compartment model with linear elimination accurately described anrikefon's PK, incorporating weight through allometric scaling. Significant covariates affecting clearance included creatinine clearance, total bilirubin, albumin, aspartate transaminase, and age. Fixed and weight-based dosing showed similar exposures. No apparent E-R trend was observed for safety endpoints. The E_max model indicated that most of subjects achieved over 90% of the maximum effect for SPID_0-24 h at 1.0 μg/kg. Safety analysis confirmed this dose was well tolerated with no safety issues.

This study provides valuable insights into dose selection, PK variability, and safety and efficacy endpoints.