Pharmacokinetics and safety of GST-HG171, a novel 3CL protease inhibitor, in Chinese subjects with impaired and normal liver function.

GST-HG171 is a potent, broad-spectrum, orally bioavailable small-molecule 3C-like (3CL) protease inhibitor that was recently approved for treating mild to moderate coronavirus disease 2019 patients in China. Since cytochrome P450 (CYP) enzymes, primarily CYP3A, are the main metabolic enzymes of GST-HG171, hepatic impairment may affect its pharmacokinetic (PK) profile. Aiming to guide clinical dosing for patients with hepatic impairment, this study, using a non-randomized, open-label, single-dose design, assessed the impact of hepatic impairment on the PK, safety, and tolerability of GST-HG171. Patients with mild and moderate hepatic impairment along with healthy subjects were enrolled (n = 8 each), receiving a single oral dose of 150 mg GST-HG171, with concurrent administration of 100 mg ritonavir to sustain CYP3A inhibition before and after GST-HG171 administration (-12, 0, 12, and 24 hours). Compared to subjects with normal hepatic function, the geometric least-squares mean ratios (90% confidence intervals) for GST-HG171's maximum plasma concentration (Cmax), area under the concentration-time curve up to the last quantifiable time (AUC0-t), and area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC0-∞) in subjects with mild hepatic impairment were 1.14 (0.99, 1.31), 1.07 (0.88, 1.30), and 1.07 (0.88, 1.29), respectively. For moderate hepatic impairment, the ratios were 0.87 (0.70, 1.07), 0.82 (0.61, 1.10), and 0.82 (0.61, 1.10), respectively. Hepatic impairment did not significantly alter GST-HG171's peak time (Tmax) and elimination half-life (T1/2). GST-HG171 exhibited good safety and tolerability in the study. Taken together, mild to moderate hepatic impairment minimally impacted GST-HG171 exposure, suggesting no need to adjust GST-HG171 dosage for patients with mild to moderate hepatic impairment in the clinic.Clinical TrialsRegistered at ClinicalTrials.gov (NCT06106113).

Efficacy and safety of GST-HG171 in adult patients with mild to moderate COVID-19: a randomised, double-blind, placebo-controlled phase 2/3 trial.

Background: GST-HG171 is a potent, broad-spectrum, orally bioavailable small-molecule 3C like protease inhibitor that has demonstrated greater potency and efficacy compared to Nirmatrelvir in pre-clinical studies. We aimed to evaluate the efficacy and safety of orally administered GST-HG171 plus Ritonavir in patients with coronavirus disease 2019 (COVID-19) infected with emerging XBB and non-XBB variants. Methods: This randomised, double-blind, placebo-controlled phase 2/3 trial was conducted in 47 sites in China among adult patients with mild-to-moderate COVID-19 with symptoms onset ≤72 h. Eligible patients were randomised 1:1 to receive GST-HG171 (150 mg) plus Ritonavir (100 mg) or corresponding placebo tablets twice daily for 5 days, with stratification factors including the risk level of disease progression and vaccination status. The primary efficacy endpoint was time to sustained recovery of clinical symptoms within 28 days, defined as a score of 0 for 11 COVID-19-related target symptoms for 2 consecutive days, assessed in the modified intention-to-treat (mITT) population. This trial was registered at ClinicalTrials.gov (NCT05656443) and Chinese Clinical Trial Registry (ChiCTR2200067088). Findings: Between Dec 19, 2022, and May 4, 2023, 1525 patients were screened. Among 1246 patients who underwent randomisation, most completed basic (21.2%) or booster (74.9%) COVID-19 immunization, and most had a low risk of disease progression at baseline. 610 of 617 who received GST-HG171 plus Ritonavir and 603 of 610 who received placebo were included in the mITT population. Patients who received GST-HG171 plus Ritonavir showed shortened median time to sustained recovery of clinical symptoms compared to the placebo group (13.0 days [95.45% confidence interval 12.0-15.0] vs. 15.0 days [14.0-15.0], P = 0.031). Consistent results were observed in both SARS-CoV-2 XBB (45.7%, 481/1053 of mITT population) and non-XBB variants (54.3%, 572/1053 of mITT population) subgroups. Incidence of adverse events was similar in the GST-HG171 plus Ritonavir (320/617, 51.9%) and placebo group (298/610, 48.9%). The most common adverse events in both placebo and treatment groups were hypertriglyceridaemia (10.0% vs. 14.7%). No deaths occurred. Interpretation: Treatment with GST-HG171 plus Ritonavir has demonstrated benefits in symptom recovery and viral clearance among low-risk vaccinated adult patients with COVID-19, without apparent safety concerns. As most patients were treated within 2 days after symptom onset in our study, confirming the potential benefits of symptom recovery for patients with a longer duration between symptom onset and treatment initiation will require real-world studies. Funding: Fujian Akeylink Biotechnology Co., Ltd.

Phase I study, and dosing regimen selection for a pivotal COVID-19 trial of GST-HG171.

This study is aimed to evaluate the safety, tolerability, and pharmacokinetics (PK), as well as to select an appropriate dosing regimen for the pivotal clinical trial of GST-HG171, an orally bioavailable, potent, and selective 3CL protease inhibitor by a randomized, double-blind, and placebo-controlled phase I trial in healthy subjects. We conducted a Ph1 study involving 78 healthy subjects to assess the safety, tolerability, and PK of single ascending doses (150-900 mg) as well as multiple ascending doses (MADs) (150 and 300 mg) of GST-HG171. Additionally, we examined the food effect and drug-drug interaction of GST-HG171 in combination with ritonavir through a MAD regimen of GST-HG171/ritonavir (BID or TID) for 5 days. Throughout the course of these studies, no serious AEs or deaths occurred, and no AEs necessitated study discontinuation. We observed that food had no significant impact on the exposure of GST-HG171. However, the presence of ritonavir substantially increased the exposure of GST-HG171, which facilitated the selection of the GST-HG171/ritonavir dose and regimen (150/100 mg BID) for subsequent phase II/III trials. The selected dose regimen was achieved through concentrations continuously at 6.2-9.9-fold above the levels required for protein-binding adjusted 50% inhibition (IC50) of viral replication in vitro. The combination of 150 mg GST-HG171/100 mg ritonavir demonstrated favorable safety and tolerability profiles. The PK data obtained from GST-HG171/ritonavir administration guided the selection of appropriate dose for a pivotal phase II/III trial currently in progress. (This study has been registered at ClinicalTrials.gov under identifier NCT05668897).

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).

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.).

Safety, Tolerability, and Pharmacokinetics of the Novel Hepatitis B Virus Capsid Assembly Modulator GST-HG141 in Healthy Chinese Subjects: a First-in-Human Single- and Multiple-Dose Escalation Trial.

Hepatitis B virus capsid assembly modulators (HBV CAMs) are promising, clinically validated therapeutic agents for the treatment of chronic hepatitis B (CHB). The safety, tolerability, and pharmacokinetic (PK) profiles of GST-HG141, a novel HBV CAM, were evaluated in healthy Chinese volunteers. This phase Ia study included two parts: a double-blinded, randomized, placebo-controlled single-ascending-dose (SAD) (50, 100, 200, 300, 400, or 500 mg) study comprising a food-effect investigation (300 mg) and a multiple-ascending-dose (MAD) (100 or 200 mg twice daily) study. GST-HG141 reached the maximum plasma concentration (Cmax) at 1.25 to 3.00 h (median Tmax). The exposure exhibited a linear increase, while the mean half-life (t1/2) ranged from 13.096 h to 22.121 h. The exposure of GST-HG141 (300 mg) was higher after food intake by about 2.4-fold. In the MAD study, steady state was reached at around day 5, and the mean trough steady-state concentrations were 423 and 588 ng/ml for 50- and 100-mg cohorts, respectively. The ratios of GST-HG141 accumulation were <1.5. GST-HG141 was well tolerated in healthy Chinese subjects. The rates of adverse events in the GST-HG141 cohort did not differ from those of the placebo cohort. GST-HG141 was tolerated in healthy Chinese subjects. The safety and PK profiles of GST-HG141 support the further evaluation of its efficacy in individuals with CHB. (This study has been registered in ClinicalTrials.gov under identifier NCT04536337.).

First-in-Man Safety, Tolerability, and Pharmacokinetics of a Novel and Highly Selective Inhibitor of Matrix Metalloproteinase-12, FP-025: Results from Two Randomized Studies in Healthy Subjects.

BACKGROUND AND OBJECTIVES: Matrix metalloproteinases (MMPs) are proteases with different biological and pathological activities, and many have been linked to several diseases. Targeting individual MMPs may offer a safer therapeutic potential for several diseases. We assessed the safety, tolerability, and pharmacokinetics of FP-025, a novel, highly selective oral matrix metalloproteinase-12 inhibitor, in healthy subjects. METHODS: Two randomized, double-blind, placebo-controlled studies were conducted. Study I was a first-in-man study, evaluating eight single ascending doses (SADs) (50-800 mg) in two formulations: i.e., neat FP-025 in capsule (API-in-Capsule) and in an amorphous solid dispersion (ASD-in-Capsule) formulation. In Study II, three multiple ascending doses (MADs) (100, 200, and 400 mg, twice daily) of FP-025 (ASD-in-Capsule) were administered for 8 days, including a food-effect evaluation. RESULTS: Ninety-six subjects were dosed. Both formulations were well tolerated with one adverse event (AE) reported in the 800 mg API-in-Capsule SAD group and seven AEs throughout the MAD groups. The exposure to FP-025 was low with the API-in-Capsule formulation; it increased dose-dependently with the ASD-in-Capsule formulation, with which exposure to FP-025 increased in a greater-than-dose-proportional manner at lower doses (≤ 100 mg) but less proportionally at higher doses. The elimination half-life (t1/2) was between 6 (Study I) and 8 h (Study II). Accumulation of FP-025 was approximately 1.7-fold in the MAD study. Food intake delayed the rate of absorption, but without effect in the extent of absorption or bioavailability. CONCLUSION: FP-025 was well tolerated and showed a favorable pharmacokinetic profile following ASD-in-Capsule dosing. Efficacy studies in target patient populations, including asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis, are warranted. TRIAL REGISTRATION NUMBER: www.clinicaltrials.gov : NCT02238834 (Study I); NCT03304964 (Study II). Trial registration date: Study I was registered on 12 September 2014 while study II was registered on 9 October 2017.

A phase 3, open-label, multicenter study of a 6-month pre-mixed depot formulation of leuprolide mesylate in advanced prostate cancer patients.

OBJECTIVES: To determine the safety, efficacy and pharmacokinetic (PK) profile of a pre-mixed depot formulation of leuprolide mesylate subcutaneous injectable suspension (LMIS) 50 mg for up to 1 year of treatment for subjects with advanced prostate cancer. PATIENTS AND METHODS: In this open-label, multicenter study, prostate cancer patients with indication for androgen ablation therapy received two subcutaneous injection of LMIS 50 mg 6 months apart and were followed for an additional 6 months. Two efficacy primary end points were the percentage of subjects with a serum testosterone level ≤ 50 ng/dL by Day 28 as well as the percentage of subjects with similar testosterone suppression from Day 28 to Day 336. RESULTS: Of the 137 enrolled subjects, 15 (10.9%) subjects did not complete the study, including 5 subjects who terminated early due to an adverse event. By Day 28, 98.5% (95% confidence interval 94.8-99.8) of the subjects achieved a castrate testosterone level. At the end of the study, 97% and 95.9% of the subjects had serum testosterone level ≤ 50 ng/dL and ≤ 20 ng/dL, respectively. LMIS 50 mg significantly reduced serum prostate-specific antigen levels after its first injection and this PSA declination effect remained until the end of the study. No statistically significant change was observed in worsening bone pain or urinary symptom assessments during the study. Hot flush (48.9%) and hypertension (14.6%) were the two most common adverse events reported. CONCLUSIONS: LMIS 50 mg, administered at 6-month intervals, effectively suppressed serum testosterone level, and demonstrated a consistent safety profile.

Safety, tolerability and pharmacodynamics of a skeletal muscle activator in amyotrophic lateral sclerosis.

This study was designed to evaluate the safety and tolerability of single doses of CK-2017357, an orally bioavailable fast skeletal muscle troponin activator, in patients with amyotrophic lateral sclerosis (ALS), and to explore pharmacodynamic markers related to strength, endurance, and function. Sixty-seven patients with ALS received single doses of placebo, CK-2017357 at 250 mg and 500 mg in random order, separated by one week. Safety measures assessments were performed, as well as tests of pulmonary function, limb muscle strength and endurance, and global impression of change. Pharmacokinetics of both CK-2017357 and riluzole were studied. Sixty-three patients completed all three dosing periods. CK-2017357 was well tolerated, with dizziness and general fatigue being the most frequent adverse events. Both patients and investigators perceived a dose-dependent benefit of CK-2017357 as measured by global impression of change. Maximum voluntary ventilation and submaximal handgrip endurance also improved. Only small changes were seen in maximal strength. In conclusion, single doses of 250 mg and 500 mg of CK-2017357 were safe and well tolerated by patients with ALS. Measures of endurance appear to be improved in a dose-related fashion, and both patients and investigators perceived a global benefit. Further study of this agent is warranted.

2'-C-Methyl branched pyrimidine ribonucleoside analogues: potent inhibitors of RNA virus replication.

RNA viruses are the agents of numerous widespread and often severe diseases. Their unique RNA-dependent RNA polymerase (RDRP) is essential for replication and, thus, constitutes a valid target for the development of selective chemotherapeutic agents. In this regard, we have investigated sugar-modified ribonucleoside analogues as potential inhibitors of the RDRP. Title compounds retain 'natural' pyrimidine bases, but possess a beta-methyl substituent at the 2'-position of the D- or L-ribose moiety. Evaluation against a broad range of RNA viruses, either single-stranded positive (ssRNA+), single-stranded negative (ssRNA-) or double-stranded (dsRNA), revealed potent activities for D-2'-C-methyl-cytidine and -uridine against ssRNA+, and dsRNA viruses. None of the L-enantiomers were active. Moreover, the 5'-triphosphates of the active D-enantiomers were found to inhibit the bovine virus diarrhoea virus polymerase. Thus, the 2'-methyl branching of natural pyrimidine ribonucleosides transforms physiological molecules into potent, broad-spectrum antiviral agents that merit further development.

Synthesis and pharmacokinetics of valopicitabine (NM283), an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine.

In our search for new therapeutic agents against chronic hepatitis C, a ribonucleoside analogue, 2'-C-methylcytidine, was discovered to be a potent and selective inhibitor in cell culture of a number of RNA viruses, including the pestivirus bovine viral diarrhea virus, a surrogate model for hepatitis C virus (HCV), and three flaviviruses, namely, yellow fever virus, West Nile virus, and dengue-2 virus. However, pharmacokinetic studies revealed that 2'-C-methylcytidine suffers from a low oral bioavailability. To overcome this limitation, we have synthesized the 3'-O-l-valinyl ester derivative (dihydrochloride form, valopicitabine, NM283) of 2'-C-methylcytidine. We detail herein for the first time the chemical synthesis and physicochemical characteristics of this anti-HCV prodrug candidate, as well as a comparative study of its pharmacokinetic parameters with those of its parent nucleoside analogue, 2'-C-methylcytidine.

Synthesis, physicochemical and pharmacokinetic studies of potential prodrugs of beta-L-2'-deoxycytidine, a selective and specific anti-HBV agent.

beta-L-2'-Deoxycytidine (beta-L-dC) is a potent, selective and specific anti-hepatitis B virus (HBV) agent. To improve its oral bioavailability, several derivatives involving sugar or base acylation, as well N4-derivatization with an N,N-(dimethylamino)methylene function, were synthesized. The physicochemical characteristics (including chemical stabilities, solubilities and distribution coefficient values) and pharmacokinetics of these compounds were determined and compared with those of the parent drug, beta-L-dC.

Phase I and pharmacokinetic study of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) using a single intravenous dose schedule.

PURPOSE: To perform a phase I and pharmacokinetics study of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) a new ribonucleotide reductase inhibitor using a single intravenous (2-h) schedule every 4 weeks. 3-AP was given at a starting dose of 5 mg/m(2) with escalation based on a modified Fibonacci scheme. PATIENTS AND METHODS: A total of 27 patients with advanced cancer were entered into the study. Doses of 3-AP ranged from 5 mg/m(2) to 105 mg/m(2). Blood and urine samples were collected and 3-AP was measured by HPLC. RESULTS: A total of 46 courses were evaluable. One patient developed grade 4 thrombocytopenia at the lowest dose level, and one patient had grade 3 anemia. Two patients developed grade 3 coagulation abnormalities. The only other toxicities of more than grade l occurring in more than 10% of patients were fever and asthenia. No toxicities were observed at the highest dose level. Peak serum concentration of 3-AP increased linearly with dose. No tumor responses were observed in this heavily pretreated population, although eight patients had stabilization of their disease. CONCLUSIONS: Relevant tumor inhibitory concentrations were achieved without significant toxicity using doses up to 105 mg/m(2) on this single intravenous dose schedule. Prolonged administration schedules and combinations with other cytotoxic agents, strategies predicted to have greater antitumor efficacy according to preclinical studies, are under investigation.

Tumor-targeted Salmonella expressing cytosine deaminase as an anticancer agent.

The study was designed to evaluate whether TAPET-CD, an attenuated strain of Salmonella typhimurium expressing Escherichia coli cytosine deaminase (CD), was capable of converting nontoxic 5-fluorocytosine (5-FC) to the active antitumor agent 5-fluorouracil (5-FU). The antitumor effect of TAPET-CD plus 5-FC against subcutaneously implanted colon tumors was also evaluated. TAPET-CD was given to tumor-bearing mice by a single bolus intravenous administration followed with 5-FC by intraperitoneal administration. TAPET-CD accumulated in tumors at levels 1000-fold higher than that in normal tissues and high levels of 5-FU were detected in tumors in mice treated with both TAPET-CD and 5-FC. No 5-FU could be detected in normal tissues. Inhibition of tumor growth was observed in mice treated with either TAPET-CD alone or TAPET-CD in combination with 5-FC (TAPET-CD/5-FC), but not with 5-FC alone. TAPET-CD/5-FC inhibited tumor growth by 88%-96%, compared to TAPET-CD alone, which inhibited tumor growth by 38%-79%. These data suggest that tumor-targeting Salmonella could be used to deliver prodrug-converting enzyme selectively to tumors and produced anti-tumor effects when the corresponding prodrug was also given.

Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma.

PURPOSE: A strain of Salmonella typhimurium (VNP20009), attenuated by chromosomal deletion of the purI and msbB genes, was found to target to tumor and inhibit tumor growth in mice. These findings led to the present phase I study of the intravenous infusion of VNP20009 to patients with metastatic cancer. PATIENTS AND METHODS: In cohorts consisting of three to six patients, 24 patients with metastatic melanoma and one patient with metastatic renal cell carcinoma received 30-minute intravenous bolus infusions containing 10(6) to 10(9) cfu/m(2) of VNP20009. Patients were evaluated for dose-related toxicities, selective replication within tumors, and antitumor effects. RESULTS: The maximum-tolerated dose was 3 x 10(8) cfu/m(2). Dose-limiting toxicity was observed in patients receiving 1 x 10(9) cfu/m(2), which included thrombocytopenia, anemia, persistent bacteremia, hyperbilirubinemia, diarrhea, vomiting, nausea, elevated alkaline phosphatase, and hypophosphatemia. VNP20009 induced a dose-related increase in the circulation of proinflammatory cytokines, such as interleukin (IL)-1beta, tumor necrosis factor alpha, IL-6, and IL-12. Focal tumor colonization was observed in two patients receiving 1 x 10(9) cfu/m(2) and in one patient receiving 3 x 10(8) cfu/m(2). None of the patients experienced objective tumor regression, including those patients with colonized tumors. CONCLUSION: The VNP20009 strain of Salmonella typhimurium can be safely administered to patients, and at the highest tolerated dose, some tumor colonization was observed. No antitumor effects were seen, and additional studies are required to reduce dose-related toxicity and improve tumor localization.

Pharmacokinetics, mass balance, and tissue distribution of a novel DNA alkylating agent, VNP40101M, in rat.

VNP40101M (1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(2 methylamino)carbonyl] hydrazine), a novel DNA alkylating agent, is currently under clinical development for the treatment of cancer in Phase I clinical trials. This study investigated the pharmacokinetics, mass balance, and tissue distribution of [14C]-VNP40101M in rats following a single intravenous dose of 10 mg/kg. After 7 days, the total recovery of radioactivity was 85% for males and 79% for females. Most of the radioactivity was eliminated within 48 hours through urine (70%), with less excreted in feces (6%). Tissue contained relatively high radioactive residues with the highest concentrations in kidneys, liver, lung, and spleen. After 7 days, tissue still contained 9% of the dose. At both 5 minutes and 1 hour post-dose, brain contained relatively high radioactivity (5.9 and 3.3 micro g equivalence/g and 50% and 30% of the blood concentration, respectively), suggesting that VNP40101M penetrated the blood-brain barrier. The elimination half-life of VNP40101M was approximately 20 minutes, the peak plasma concentration (Cmax) averaged 11.3 micro g/mL, the volume of distribution (Vss) averaged 0.91 L/kg, and the total body clearance (Cl) averaged 33.5 mL/min/kg. The metabolite profile in urine was complex, indicating VNP40101M was extensively metabolized. There were no apparent sex differences in pharmacokinetic parameters of VNP40101M in the rat.