A phase 3, randomized, double-blind, sham-controlled trial of SI-6603 (condoliase) in patients with radicular leg pain associated with lumbar disc herniation.

BACKGROUND CONTEXT: SI-6603 (condoliase) is a chemonucleolytic agent approved in Japan in 2018 for the treatment of lumbar disc herniation (LDH) associated with radicular leg pain. Condoliase, a mucopolysaccharidase with high substrate specificity for glycosaminoglycans (GAGs), offers a unique mechanism of action through the degradation of GAGs in the nucleus pulposus. As LDH management is currently limited to conservative approaches and surgical intervention, condoliase could offer a less invasive treatment option than surgery for patients with LDH. PURPOSE: The Discover 6603 study (NCT03607838) evaluated the efficacy and safety of a single-dose injection of SI-6603 (condoliase) vs sham for the treatment of radicular leg pain associated with LDH. STUDY DESIGN/SETTING: A randomized, double-blind, sham-controlled, phase 3 study conducted across 41 sites in the United States. PATIENT SAMPLE: Male and female participants (N=352; aged 30-70 years) with contained posterolateral LDH and unilateral radiculopathy/radicular leg pain for greater than 6 weeks. OUTCOME MEASURES: The primary endpoint was the change from baseline (CFB) in average worst leg pain score at 13 weeks, assessed using the 100-mm visual analogue scale. Key secondary endpoints were CFB in average worst leg pain score at 52 weeks, herniation volume at 13 weeks, and Oswestry Disability Index (ODI) score at 13 weeks. Safety evaluations included adverse events (AEs) and imaging findings. METHODS: Participants were randomized 1:1 to receive a single intradiscal injection of condoliase (1.25 units) or sham injection followed by 52 weeks of observation. The primary and key secondary endpoints were assessed using a mixed model for repeated measures (MMRM) analysis and a protocol-specified multiple imputation (MI) sensitivity analysis on the modified intention-to-treat (mITT) population. A prespecified serial gatekeeping algorithm was used for multiple comparisons. Safety endpoints included AEs, laboratory tests, vital signs, imaging (by X-ray and magnetic resonance imaging [MRI]), and occurrence of posttreatment lumbar surgery. RESULTS: Of the 352 randomized participants, 341 constituted the mITT population (condoliase n=169; sham n=172) and the safety population (condoliase n=167; sham n=174). For the primary endpoint, the condoliase group showed significantly greater improvement in CFB in worst leg pain at Week 13 (least squares mean [LSM] CFB: -41.7) compared with sham injection (-34.2; LSM difference: -7.5; 95% confidence interval [CI]: -14.1, -0.9; p=.0263) based on the MMRM analysis. CFB in worst leg pain at Week 52 favored condoliase vs sham, but the difference was not statistically significant (p=.0558), which halted the serial gatekeeping testing algorithm and dictated that the CFB in herniation volume and ODI scores at Week 13 would be considered nonsignificant, regardless of their p-values. Treatment group differences in CFB in herniation volume and ODI score favored the condoliase group vs sham at all timepoints. The MI sensitivity analysis showed differences in CFB in worst leg pain at Week 13 (p=.0223) and Week 52 (p=.0433) in favor of the condoliase group. Treatment-emergent AEs (TEAEs) were more common in the condoliase group (≥1 TEAE: 71.9%; ≥1 treatment-related TEAE: 28.1%) compared with the sham group (≥1 TEAE: 60.3%; ≥1 treatment-related TEAE: 10.3%). Of the TEAEs, spinal MRI abnormalities and back pain occurred most frequently. No treatment-related serious AEs occurred. CONCLUSIONS: Condoliase met its primary endpoint of significantly improving radicular leg pain at Week 13 and was generally well tolerated in patients with LDH. Chemonucleolysis with condoliase has the potential to provide a less invasive treatment option than surgery for those unresponsive to conservative treatment strategies.

Condoliase chemonucleolysis for lumbar disc herniation: A post-hoc follow-up study of patients in previous clinical trials.

BACKGROUND: Chemonucleolysis with condoliase significantly improved clinical symptoms in patients with lumbar disc herniation. We evaluated the surgical intervention rate and outcomes for >1 year after condoliase treatment. METHODS: This was a follow-up study of patients who received condoliase or placebo in two previous randomized, placebo-controlled clinical trials with 1-year follow-ups. A post-treatment surgery survey and on-site examination were administered and patients' data from the clinical trial records and additional interview data were analyzed to evaluate the surgical intervention rate. Patients' lumbar disease symptoms, Oswestry Disability Index, and imaging features were evaluated. RESULTS: Among the patients (condoliase, n = 228; placebo, n = 128) enrolled in the clinical trials, additional post-treatment surgery data were available for 231 patients after the clinical trials ended, and 179 patients underwent post-trial examinations, at least 5 years and 17 months after the end of the clinical trials. The surgical intervention rate in the placebo and condoliase groups was 20.7% (95% confidence interval: 14.2-29.7) and 13.4% (95% confidence interval: 8.8-20.2), respectively. The mean change in Oswestry Disability Index score from pre-injection in placebo and condoliase groups was -24.7 ± 15.0 and -32.7 ± 18.6 (between-group difference: -8.0 ± 17.3; 95% confidence interval: -13.2 to -2.7). Modic Type 2 changes were observed, particularly in the condoliase group. No relationship between lumbar disease symptoms and change in imaging features was found. CONCLUSIONS: This follow-up study more than 1 year revealed no new safety concerns of condoliase. However, because the study had several limitations, such as large loss of follow-up, further research is needed.

Diclofenac-hyaluronate conjugate (diclofenac etalhyaluronate) intra-articular injection for hip, ankle, shoulder, and elbow osteoarthritis: a randomized controlled trial.

BACKGROUND: To evaluate the efficacy and safety of intra-articular injection of diclofenac etalhyaluronate (DF-HA) in patients with osteoarthritis (OA) of the hip, ankle, shoulder, or elbow. METHODS: In this randomized, placebo-controlled, double-blind study in Japan, Japanese patients aged ≥20 years diagnosed with OA of the hip, ankle, shoulder, or elbow were randomly assigned 1:1 to DF-HA 30 mg or placebo (citric acid-sodium citrate buffered solution). Subjects received three injections of the study drug in each joint cavity every 4 weeks and were assessed for 12 weeks after the first injection. The primary endpoint was the mean change from baseline in a diary-based 11-point numerical rating scale (NRS) for pain over 12 weeks, analyzed for each joint. Treatment-emergent adverse events were recorded, and morphological changes in each joint were evaluated radiographically. RESULTS: The study drug (DF-HA vs placebo) was injected into 90, 60, 90, or 50 subjects with OA of the hip, ankle, shoulder, or elbow (46 vs 44, 30 vs 30, 45 vs 45, and 25 vs 25, respectively). The group differences in the mean change from baseline in the pain NRS over 12 weeks were - 0.81 (95% confidence interval: - 1.48 to - 0.13), - 0.07 (- 1.03 to 0.89), 0.15 (- 0.48 to 0.78), and 0.61 (- 0.41 to 1.62) for the hip, ankle, shoulder, and elbow joints, respectively, with statistically significant differences observed only in the hip joint. The change from baseline in the hip joint was greater with DF-HA than placebo at all time points from Weeks 1-12. No clinically significant adverse events or radiographic changes were observed. CONCLUSIONS: Intra-articularly administered DF-HA for hip OA produced a rapid response and was safe, with analgesia maintained for 12 weeks when administered every 4 weeks. TRIAL REGISTRATION: JapicCTI-173,678 (First registered date: 21 August 2017).

Efficacy and Safety of Diclofenac-Hyaluronate Conjugate (Diclofenac Etalhyaluronate) for Knee Osteoarthritis: A Randomized Phase III Trial in Japan.

OBJECTIVE: To confirm the efficacy and safety of intraarticular (IA) injection of diclofenac covalently linked to hyaluronic acid (diclofenac etalhyaluronate [DF-HA]; ONO-5704/SI-613) in patients with knee osteoarthritis (OA). METHODS: In a phase III multicenter, randomized, double-blind, placebo-controlled trial, eligible subjects ages 40-75 years with symptomatic knee OA (Kellgren/Lawrence score of 2 or 3) were randomly assigned to receive IA injections of DF-HA 30 mg or placebo (citric acid-sodium citrate buffered solution; 1:1) once every 4 weeks for 20 weeks (a total of 6 injections). Subjects were followed up for 24 weeks. The primary end point was the mean change from baseline to 12 weeks in Western Ontario and McMaster Universities Osteoarthritis Index version 3.1 (WOMAC) pain subscale scores, measured on a 100-mm visual analog scale. Safety was evaluated by adverse event monitoring. RESULTS: All 440 subjects received investigational products (220 received placebo and 220 received DF-HA). The full analysis set and safety population comprised 438 subjects (220 in the placebo group and 218 in the DF-HA group) and 440 subjects, respectively. At 12 weeks, subjects receiving DF-HA showed significant improvement from baseline in the WOMAC pain subscale score (-23.2 mm) compared to subjects receiving placebo ( -17.1 mm), with a difference of -6.1 mm (95% confidence interval -9.4, -2.8; P < 0.001). The difference between groups was significant as early as week 1, and a difference was maintained for 24 weeks, although the difference at week 24 was not significant. Anaphylactic reactions were observed in 2 subjects receiving DF-HA. CONCLUSION: Our findings indicate that treatment with DF-HA results in significant improvement in the WOMAC pain subscale score compared to placebo over 12 weeks. Anaphylactic reactions were observed, and further safety evaluation is needed.

Open-label phase 3 study of diclofenac conjugated to hyaluronate (diclofenac etalhyaluronate: ONO-5704/SI-613) for treatment of osteoarthritis: 1-year follow-up.

BACKGROUND: We evaluated the 1-year safety and efficacy of diclofenac etalhyaluronate (DF-HA), a diclofenac-conjugated hyaluronate, in patients with osteoarthritis (OA). METHODS: In this multi-centre, open-label, noncomparative phase 3 study in Japan, patients with a diagnosis of knee, shoulder, elbow, hip, or ankle OA received an intra-articular (IA) injection of DF-HA 30 mg every 4 weeks for 1 year (13 times in total). The safety outcomes included treatment-emergent adverse events (TEAEs) and target joint structural changes by X-ray imaging tests. Efficacy outcomes included joint pain scores on an 11-point numerical rating scale. Concomitant use of analgesics was not restricted. RESULTS: Overall, 166 eligible patients were enrolled, comprising knee OA (n = 126) and other OA (n = 40). All TEAEs were experienced by 126/166 patients (75.9%). The incidence of treatment-related TEAEs was not associated with the treatment period. No significant worsening of joint status was observed in X-ray imaging tests at week 52 or at last assessment. The mean joint pain scores (± standard deviation) were 5.9 ± 1.2, 4.9 ± 1.9, and 3.1 ± 2.3 at baseline, and weeks 2 and 52, respectively. Improvement of pain score was observed after the first injection and was maintained until week 52 regardless of knee OA or other joint OA. CONCLUSIONS: Repeated IA injections of DF-HA every 4 weeks for 1 year were well tolerated with no clinically significant adverse events indicating they might lead to the long-term improvement of OA symptoms. DF-HA might be a useful treatment for patients with OA. TRIAL REGISTRATION NUMBER: JapicCTI-183855 (First registered date: 6th February 2018).

Sustained-release diclofenac conjugated to hyaluronate (diclofenac etalhyaluronate) for knee osteoarthritis: a randomized phase 2 study.

OBJECTIVE: To evaluate the efficacy and safety of diclofenac etalhyaluronate (DF-HA) (ONO-5704/SI-613), a novel DF-conjugated hyaluronate, in patients with knee OA in Japan. METHODS: In this randomized, double-blind, placebo-controlled phase 2 study, patients were randomly assigned (1:1) to receive either 30 mg of DF-HA or placebo intra-articularly at weeks 0, 4 and 8 and were followed up for 24 weeks. The primary outcomes were changes from baseline in the WOMAC pain subscores, 50-foot walk test pain score and daily pain score. The secondary outcomes were the WOMAC physical function subscores, patient global assessment, responder rate and safety outcome. RESULTS: Overall, 176 patients received the investigational drugs (87 received DF-HA and 89 received placebo). The mean changes in the WOMAC pain subscores and daily pain score from baseline over 12 weeks after the first injection were significantly higher in the DF-HA than placebo group; the mean difference was -7.0 mm [95% CI, -12.7, -1.2; P =0.018] and -0.61 (95% CI, -1.06, -0.16; P =0.008), respectively. The difference in the 50-foot walk test pain score was -5.0 mm (95% CI, -10.3, 0.3; P =0.065). Improvement of pain by DF-HA was observed at week 1 and maintained from week 12 to week 24. Significantly greater improvements in the secondary outcomes were also observed with DF-HA than with placebo. No clinically significant adverse events occurred. CONCLUSION: DF-HA reduced pain in patients with knee OA without major safety concerns. TRIAL REGISTRATION: UMIN Clinical Trials Registry, https://www.umin.ac.jp/ctr/index.htm, UMIN000015858.

A Single Intra-Articular Injection of Gel-200 for Treatment of Symptomatic Osteoarthritis of the Knee Is More Effective than Phosphate Buffered Saline at 6 Months: A Subgroup Analysis of a Multicenter, Randomized Controlled Trial.

OBJECTIVE: Many clinical trials of viscosupplementation have been conducted, although only the Gel-200 (primary) trial included a different patient population. A subgroup analysis of a multicenter, randomized controlled trial comparing the efficacy of single intra-articular injections of Gel-200 with phosphate buffered saline (PBS) was performed to demonstrate its benefit as treatment of osteoarthritis of the knee in a population similar to those of other reported trials of viscosupplementation. DESIGN: The subgroup population was defined as patients in the intention-to-treat (ITT) population who met the specified criteria. Changes from baseline in Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores following treatment with Gel-200 or PBS were derived from a longitudinal model and treatment differences compared between groups at weeks 12 and 26, and over 26 weeks. RESULTS: The subgroup included 311 subjects (152 Gel-200; 159 PBS). Mean improvements from baseline in WOMAC pain subscores in the Gel-200 over PBS groups were statistically significant at week 12 (P = 0.031) and week 26 (P = 0.019). Treatment group differences in WOMAC stiffness and total scores were statistically significant at week 26 (P = 0.023 and P = 0.036, respectively). CONCLUSIONS: The efficacy of Gel-200 following a single injection for knee osteoarthritis was demonstrated in WOMAC pain, stiffness, and total scores as well as clinically important improvements in pain at 26 weeks in this subset of patients with comparable characteristics to populations evaluated in other viscosupplementation treatment trials.

A Pooled Analysis of Two Multicenter, Randomized Controlled Trials of a Single Intra-articular Injection of Gel-200 for Treatment of Osteoarthritis of the Knee.

BACKGROUND AND OBJECTIVE: To perform an integrated analysis of 2 randomized controlled trials (RCTs) to assess the efficacy and safety of a single intra-articular injection of Gel-200 compared with phosphate buffered saline (PBS) for treatment of osteoarthritis of the knee. METHODS: Data from the intention-to-treat (ITT) populations of both RCTs were pooled for this integrated analysis. Mean changes from baseline in Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain subscores were assessed using a longitudinal model; treatment differences were compared between intra-articular Gel-200 and PBS injections. Analyses included secondary outcome measures repeated at individual time points. The safety populations of both RCTs were pooled for an integrated safety analysis to compare adverse events (AEs). RESULTS: The pooled ITT population included 1184 subjects (649 Gel-200; 535 PBS); demographic characteristics were similar between treatment groups. Mean improvements in pain subscores from baseline to week 12 were -24.7 mm in Gel-200 and -21.8 mm in PBS groups, a statistically significant treatment group difference of -2.9 mm (P = .047). From weeks 3 to 26, mean improvements from baseline in pain subscores were -23.8 mm with Gel-200 and -20.8 mm with PBS; this treatment group difference of -3.0 mm was statistically significant (P = .017). The rate of AEs was similar between Gel-200 and PBS treatment groups. CONCLUSION: This integrated analysis demonstrated the efficacy of a single intra-articular injection of Gel-200 compared with PBS for treatment of osteoarthritis of the knee over 26 weeks without major safety concerns. TRIAL REGISTRATION: NCT00449696 and NCT00450112.

A multicenter, randomized, double-blind, dose-finding study of condoliase in patients with lumbar disc herniation.

OBJECTIVE Chemonucleolysis with condoliase has the potential to be a new, less invasive therapeutic option for patients with lumbar disc herniation (LDH). The aim of the present study was to determine the most suitable therapeutic dose of condoliase. METHODS Patients between 20 and 70 years of age with unilateral leg pain, positive findings on the straight leg raise test, and LDH were recruited. All eligible patients were randomly assigned to receive condoliase (1.25, 2.5, or 5 U) or placebo. The primary end point was a change in the worst leg pain from preadministration (baseline) to week 13. The secondary end points were changes from baseline in the following items: worst back pain, Oswestry Disability Index (ODI), SF-36, and neurological examination. For pharmacokinetic and pharmacodynamic analyses, plasma condoliase concentrations and serum keratan sulfate concentrations were measured. The safety end points were adverse events (AEs) and radiographic and MRI parameters. Data on leg pain, back pain, abnormal neurological findings, and imaging parameters were collected until week 52. RESULTS A total of 194 patients received an injection of condoliase or placebo. The mean change in worst leg pain from baseline to week 13 was -31.7 mm (placebo), -46.7 mm (1.25 U), -41.1 mm (2.5 U), and -47.6 mm (5 U). The differences were significant at week 13 in the 1.25-U group (-14.9 mm; 95% CI -28.4 to -1.4 mm; p = 0.03) and 5-U group (-15.9 mm; 95% CI -29.0 to -2.7 mm; p = 0.01) compared with the placebo group. The dose-response improvement in the worst leg pain at week 13 was not significant (p = 0.14). The decrease in the worst leg pain in all 3 condoliase groups was observed from week 1 through week 52. Regarding the other end points, the worst back pain and results of the straight leg raise test, ODI, and SF-36 showed a tendency for sustained improvement in each of the condoliase groups until week 52. In all patients at all time points, plasma condoliase concentrations were below the detectable limit (< 100 µU/ml). Serum keratan sulfate concentrations significantly increased from baseline to 6 hours and 6 weeks after administration in all 3 condoliase groups. No patient died or developed anaphylaxis or neurological sequelae. Five serious AEs occurred in 5 patients (3 patients in the condoliase groups and 2 patients in the placebo group), resolved, and were considered unrelated to the investigational drug. Severe AEs occurred in 10 patients in the condoliase groups and resolved or improved. In the condoliase groups, back pain was the most frequent AE. Modic type 1 change and decrease in disc height were frequent imaging findings. Dose-response relationships were observed for the incidence of adverse drug reactions and decrease in disc height. CONCLUSIONS Condoliase significantly improved clinical symptoms in patients with LDH and was well tolerated. While all 3 doses had similar efficacy, the incidence of adverse drug reactions and decrease in disc height were dose dependent, thereby suggesting that 1.25 U would be the recommended clinical dose of condoliase. Clinical trial registration no.: NCT00634946 (clinicaltrials.gov).

Condoliase for the Treatment of Lumbar Disc Herniation: A Randomized Controlled Trial.

STUDY DESIGN: A randomized, double-blind, placebo-controlled, multicenter phase III clinical trial. OBJECTIVE: To evaluate the efficacy and safety of chemonucleolysis with condoliase in patients with lumbar disc herniation (LDH). SUMMARY OF BACKGROUND DATA: Condoliase is a pure mucopolysaccharidase derived from a bacterium, Proteus vulgaris that has high substrate specificity for chondroitin sulfate and hyaluronic acid in the nucleus pulposus of the intervertebral disc. METHODS: In this study, patients aged 20 to 70 years with unilateral leg pain, positive straight leg raise test, and a contained LDH were recruited in Japan. Patients were treated with a single injection of condoliase (1.25 U) or placebo and were followed for 1 year after administration. The primary endpoint was change in worst leg pain from baseline to week 13. The secondary endpoints included responder rate, and the changes from baseline up to week 52 in the worst leg pain, worst back pain, Oswestry Disability Index, 36-Item Short-Form Health Survey, neurologic examinations, and imaging parameters. RESULTS: A total of 82 and 81 patients received an injection of condoliase and placebo, respectively. The average changes in worst leg pain from baseline to week 13 (primary endpoint) were -49.5 mm in the condoliase group and -34.3 mm in the placebo group, and the difference of -15.2 mm was significant (95% confidence interval, -24.2 to -6.2; P = 0.001). Significant improvements were observed in the condoliase groups, compared with the placebo group, in most secondary endpoints at 1 year after administration. In the condoliase group, back pain, Modic type 1 change, and decrease in disc height were frequently reported, without any clinically relevant consequences. CONCLUSION: Condoliase significantly improved symptoms in patients with LDH and was well tolerated. Condoliase is a novel and potent chemonucleolytic drug for the treatment of LDH. LEVEL OF EVIDENCE: 1.

Effects of CYP2C19 and P450 oxidoreductase polymorphisms on the population pharmacokinetics of clobazam and N-desmethylclobazam in japanese patients with epilepsy.

BACKGROUND: Clobazam (CLB) is a 1,5-benzodiazepine with antiepileptic properties. More than 70% of administered CLB is dealkylated to yield N-desmethylclobazam (N-CLB), a pharmacologically active metabolite, by cytochrome P450 (CYP) 3A4 and CYP2C19. The subsequent inactivation of N-CLB is primarily catalyzed by CYP2C19. Meanwhile, P450 oxidoreductase (POR) is the obligatory electron donor to all microsomal CYP enzymes. The aim of this study was to evaluate the impact of the CYP2C19 and POR genotypes on the pharmacokinetic parameters of CLB and N-CLB. METHODS: This retrospective study included 85 Japanese patients with epilepsy who were treated with CLB. CYP2C19*2, *3, and P450 oxidoreductase (POR) *28 (rs1057868C>T) polymorphisms were evaluated. A total of 128 steady-state concentrations for both CLB and N-CLB were collected from the patients. A nonlinear mixed-effects model identified the pharmacokinetics of CLB and N-CLB; the covariates included CYP2C19 and POR genotypes, weight, gender, daily CLB dose, and coadministered antiepileptic drugs. RESULTS: Among the 85 patients, the allele frequencies of CYP2C19*2, CYP2C19*3, and POR*28 were 27.6%, 12.9%, and 41.2%, respectively. A one-compartment model with first-order absorption and/or elimination showed that the clearance of CLB and N-CLB was significantly lower by 18.1% and 84.9%, respectively, in the CYP2C19 poor metabolizers compared with the homozygous extensive metabolizers. The CLB clearance was 44% higher in subjects homozygous for the POR*28 T allele than in those homozygous for the POR*28 C allele, although the genotypes did not affect the N-CLB clearance. The concomitant use of phenobarbital, phenytoin, and zonisamide significantly affected the CLB clearance, whereas that of carbamazepine, phenytoin, and valproic acid affected the N-CLB clearance. The weight also significantly influenced the CLB clearance and volume of distribution of both CLB and N-CLB. CONCLUSIONS: Our results showed that the CYP2C19 and/or POR genotypes have an impact on the CLB and/or N-CLB clearance. These results suggest that determining the CYP2C19 and/or POR genotypes is helpful for obtaining appropriate serum CLB and N-CLB concentrations and preventing an overdose when starting CLB therapy.

Population estimation regarding the effects of cytochrome P450 2C19 and 3A5 polymorphisms on zonisamide clearance.

We aimed to evaluate the effects of cytochrome P450 (CYP) 2C19 and CYP3A5 polymorphisms on zonisamide (ZNS) clearance. The pharmacokinetics of the 282 ZNS concentrations at a steady state obtained from 99 Japanese epileptic patients was performed with a nonlinear mixed-effect modeling program, using a one-compartment open pharmacokinetic model with first-order elimination. The covariates screened included the total body weight, gender, ZNS daily dose, CYP2C19 and CYP3A5 genotypes, and the coadministered antiepileptic drugs. The final model of ZNS apparent clearance was as follows: CL = 1.22 x (BW/44)0.77 x DOSE(-0.17 x 0.84CYP2C19 hetero EM x 0.70CYP2C19 PM x 1.24CBZ x 1.28PHT x 1.29PB x eetaCL where CL is the apparent oral clearance of ZNS, DOSE is ZNS daily dose, and CYP2C19 heterozygous extensive metabolizer (EM) or CYP2C19 poor metabolizer (PM) is equal to 1 if one or two CYP2C19-defective alleles are carried, respectively; otherwise, it is 0. Carbamazepine (CBZ), phenytoin (PHT), or phenobarbital (PB) is equal to 1 if carbamazepine, phenytoin, or phenobarbital is coadministered, respectively; otherwise, it is 0. etaCL is the independent random error distributed normally with the mean zero and variance equal to omegaCL. The CL of ZNS was lower in the CYP2C19 heterozygous extensive metabolizers and poor metabolizers than in the homozygous extensive metabolizers by 16% and 30%, respectively (P < 0.001). An effect of CYP3A5 polymorphisms was not identified. The coadministration of carbamazepine, phenytoin, or phenobarbital increased the CL of ZNS by 24% to 29%. This report demonstrates that the CYP2C19 genotype affects the ZNS metabolism in Japanese epileptic subjects. The clinical relevance of these changes remains to be explored in future studies.

Association between cytochrome P450 3A5 polymorphism and the lung function in Saskatchewan grain workers.

OBJECTIVE: The activity of the enzymes that metabolize tobacco smoke may affect the susceptibility to chronic obstructive pulmonary disease (COPD). Cytochrome P450 (CYP) 3A5 is expressed selectively over CYP3A4 in human lung, but the association between the CYP3A5 polymorphisms and the airway injury is unknown. METHODS: Two hundred and six male Saskatchewan grain workers participated in this longitudinal study, and their lung function values of forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC), respiratory symptoms, smoking status, and the occupational history were analyzed. RESULTS: A significant interactive effect was observed between the CYP3A5 genotype and current smoking status on FEV1, and the annual decline rates of FEV1 and FVC in current smokers were greater among CYP3A5*1/*3 carriers than CYP3A5*3/*3 carriers (-48.7+/-16.4 vs. -31.5+/-4.7 ml/years, P=0.02; -27.4+/-18.9 vs. -5.8+/-6.5 ml/years, P=0.04). The incidences of chronic cough and COPD were also higher in current smokers with CYP3A5*1/*3 than in nonsmokers and current smokers with CYP3A5*3/*3. The adjusted odds ratios for chronic cough and COPD current smokers with CYP3A5*1/*3 versus nonsmokers with the CYP3A5*3/*3 genotype were 11.4 (P=0.009) and 4.3 (P=0.13), respectively. CONCLUSION: The results suggest that CYP3A5*1 may be a novel genetic risk factor for airway injury in smokers, and that CYP3A5 may play a role in airway injury owing to the bioactivation of chemicals in tobacco smoke.

Association between SCN1A polymorphism and carbamazepine-resistant epilepsy.

AIMS: To establish whether the SCN1A IVS5-91 G > A polymorphism of the SCN1A gene, which encodes the neuronal sodium channel alpha subunit, affects responsiveness to the antiepileptic drugs (AEDS) carbamazepine and/or phenytoin. METHODS: SCN1A IVS5-91 G > A polymorphism was genotyped in 228 Japanese epileptic patients treated with AEDs. The association between AED responsiveness and the polymorphism was estimated by logistic regression analysis, adjusting for clinical factors affecting the outcome of AED therapy. RESULTS: The frequency of the AA genotype was significantly higher in carbamazepine-resistant patients (odds ratio, 2.7; 95% confidence interval (CI), 1.1, 7.1) and was insignificantly higher in AED-resistant patients. CONCLUSIONS: This is the first report demonstrating an association between the SCN1A polymorphism and carbamazepine-resistant epilepsy.

Impact of CYP2C19 polymorphisms on the efficacy of clobazam therapy.

BACKGROUND: Clobazam-induced adverse reactions have been reported in cases with CYP2C19 defective allele(s). However, the relevance of the CYP2C19 genotypes to clobazam therapy remains to be clarified. METHODS: The association between CYP2C19 genotypes and the antiepileptic and adverse effects of clobazam was retrospectively investigated in 110 Japanese subjects, in relation to clobazam and N-desmethylclobazam (N-clobazam) concentrations. RESULTS: There were 41 (37.3%) homozygous extensive metabolizers (EMs), 44 (40.0%) heterozygous EMs, and 25 (22.7%) poor metabolizers (PMs). The response rate was significantly greater in PMs and heterozygous EMs than homozygous EMs with a gene-dose effect (65.2, 47.6 and 33.3%, respectively), and the adjusted odds ratio (95% CI) of PM versus homozygous EMs was 9.88 (2.47-39.56; p = 0.001). However, the genotypes did not affect the development of tolerance or adverse reactions, although the incidence of some adverse symptoms was insignificantly higher in PMs. The N-clobazam concentration (microg/ml) increased with the number of CYP2C19-defective alleles (0.92 +/- 0.61, 2.14 +/- 1.69 and 7.70 +/- 6.04, respectively; p < 0.001), while the clobazam concentration was 1.5-fold greater in those with at least one variant. CONCLUSION: CYP2C19 genotype had an impact on the efficacy of clobazam, thus indicating that N-clobazam plays an important role in long-term clobazam therapy.

ABCC2 haplotype is not associated with drug-resistant epilepsy.

Several studies have investigated the association between the ABCB1 polymorphism and drug-resistant epilepsy. However, the effect of ABCC2 polymorphisms on anti-epileptic drug (AED) responsiveness remains unknown. The ABCC2 polymorphisms have been genotyped in 279 Japanese epileptic patients treated with AEDs. The association between the AED responsiveness and the polymorphisms was estimated by a haplotype-based analysis. No genotype or haplotype was associated with drug-resistant epilepsy. On the other hand, the delGCGC haplotype at G-1774delG, C-24T, G1249A and C3972T was over represented among the epileptic patients with a complication of mental retardation in comparison with those without (32.4% vs 22.0%; P=0.009); and the G-1774delG allele was also associated with mental retardation (P=0.03). No association between the ABCC2 genotypes or haplotypes, and the responsiveness of AEDs was observed, although this finding was inconclusive because of the small sample size.

Potential relationships between transaminase abnormality and valproic acid clearance or serum carnitine concentrations in Japanese epileptic patients.

This study tested the hypothesis that the determinants of mild liver injury are prerequisites for more severe idiosyncratic hepatotoxicity. This study verified whether the possible risk factors for rare idiosyncratic valproic acid (VPA)-induced hepatotoxicity, VPA clearance and/or serum carnitine concentrations are common to those for a mild elevation in transaminases in VPA-treated patients. VPA clearance was calculated in 172 Japanese patients with epilepsy, using a non-linear mixed-effects regression program. Carnitine concentrations were determined in a subset of 60 patients. The relationships between VPA clearance, carnitine concentration and levels of transaminases and ammonia were evaluated by Pearson's correlation coefficients. The final model of VPA apparent clearance (CL/F) was as follows: CL/F (L h(-1) = 0.012 x (BW/40)(0.34) x dose(0.55) x 0.90(gender) x 1.32(PHT) x 1.11(CBZ) x 1.12(PB), where BW = total body weight (kg); gender = 1 if female, 0 if male; PHT/CBZ/PB = 1 if phenytoin, carbamazepine, or phenobarbital, respectively, is coadministrated, otherwise 0. Either a higher VPA clearance or acyl/free carnitine ratio and a lower total and/or free carnitine concentration, but not VPA concentration, were associated with the mild elevation in transaminases or ammonia. These results support the initial hypothesis, while also helping to clarify the mechanism of severe idiosyncratic hepatotoxicity with VPA.

Interactive effect of paraoxonase-1 Q192R polymorphism and smoking history on the lung function decline in grain workers.

PURPOSE: This retrospective longitudinal study investigated the association between the Q192R polymorphism of the high-density lipoprotein-associated multifunctional antioxidant enzyme, paraoxonase-1 (PON1), and lung function decline, while taking into account smoking history. METHODS: The demographic, occupational, and respiratory symptom information and lung function variables were obtained from 216 male Saskatchewan grain workers. RESULTS: An interaction between the PON1 genotypes and smoking status was observed. Current smokers with the 192R allele had a lower forced expiratory volume in the first second (FEV(1)) and FEV(1) per forced vital capacity (FVC). The annual decline rate of FEV(1)/FVC in current smokers was greater among 192R allele carriers than noncarriers (0.58+/-0.05 vs. 0.35+/-0.04 %/yr, p<0.0001). A similar result was observed with FEV(1) (40.9+/-6.4 vs. -33.0+/-7.0 mL/yr, p=0.10). The annual decline rate of FVC was not influenced by the genotypes. CONCLUSIONS: These results strengthened the previous findings of our cross-sectional study, suggesting that the 192R allele may be a novel genetic risk factor for airway injury among current smokers.

Glutathione-S-transferase (GST) M1 null genotype and combined GSTM1 and GSTT1 null genotypes are risk factors for increased serum gamma-glutamyltransferase in valproic acid-treated patients.

BACKGROUND: This study was designed to verify whether the glutathione S-transferase (GST) genotypes affect mild hepatotoxicity in valproic acid (VPA)-treated patients. METHODS: The association between the GSTM1 and GSTT1 genotypes, and the levels of aminotransferases and total bilirubin was retrospectively investigated in 149 Japanese epileptic patients treated with VPA. RESULTS: The adjusted odds ratio (OR) of the GSTM1- vs. GSTM1+ genotype and the GSTM1-/GSTT1-vs. GSTM1+/GSTT1+ genotypes for gamma-glutamyltransferase (GGT) increase over the upper limit of normal were 2.8 [95% confidence interval (CI): 1.1-7.2] and 6.5 (95% CI: 1.5-28.0), respectively. The GSTT1 genotypes alone did not significantly affect the liver function tests. The alanine aminotransferase, aspartate aminotransferase and (gamma-glutamyltransferase) GGT levels in patients treated with VPA >6 months were significantly higher in the GSTM1- than GSTM1+ genotype. The GGT levels were significantly higher in the older subjects receiving polytherapy, and the effects of the polytherapy and age were greater in the GSTM1- genotype. CONCLUSIONS: The GSTM1- and GSTM1-/GSTT1- genotypes may be a genetic risk factor for the increase of GGT in VPA-treated patients. However, it was not possible to clarify whether the GGT increase was caused by VPA-induced hepatotoxicity or not.