MS disease activity in RESTORE: a randomized 24-week natalizumab treatment interruption study.

OBJECTIVE: RESTORE was a randomized, partially placebo-controlled exploratory study evaluating multiple sclerosis (MS) disease activity during a 24-week interruption of natalizumab. METHODS: Eligible patients were relapse-free through the prior year on natalizumab and had no gadolinium-enhancing lesions on screening brain MRI. Patients were randomized 1:1:2 to continue natalizumab, to switch to placebo, or to receive alternative immunomodulatory therapy (other therapies: IM interferon ß-1a [IM IFN-ß-1a], glatiramer acetate [GA], or methylprednisolone [MP]). During the 24-week randomized treatment period, patients underwent clinical and MRI assessments every 4 weeks. RESULTS: Patients (n = 175) were randomized to natalizumab (n = 45), placebo (n = 42), or other therapies (n = 88: IM IFN-ß-1a, n = 17; GA, n = 17; MP, n = 54). Of 167 patients evaluable for efficacy, 49 (29%) had MRI disease activity recurrence: 0/45 (0%) natalizumab, 19/41 (46%) placebo, 1/14 (7%) IM IFN-ß-1a, 8/15 (53%) GA, and 21/52 (40%) MP. Relapse occurred in 4% of natalizumab patients and in 15%-29% of patients in the other treatment arms. MRI disease activity recurred starting at 12 weeks (n = 3 at week 12) while relapses were reported as early as 4-8 weeks (n = 2 in weeks 4-8) after the last natalizumab dose. Overall, 50/167 patients (30%), all in placebo or other-therapies groups, restarted natalizumab early because of disease activity. CONCLUSIONS: MRI and clinical disease activity recurred in some patients during natalizumab interruption, despite use of other therapies. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with MS taking natalizumab who are relapse-free for 1 year, stopping natalizumab increases the risk of MS relapse or MRI disease activity as compared with continuing natalizumab.

Risk of natalizumab-associated progressive multifocal leukoencephalopathy.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is associated with natalizumab treatment. We quantified the risk of PML in patients with multiple sclerosis, according to the presence or absence of three risk factors: positive status with respect to anti-JC virus antibodies, prior use of immunosuppressants, and increasing duration of natalizumab treatment. METHODS: We used data from postmarketing sources, clinical studies, and an independent Swedish registry to estimate the incidence of PML among natalizumab-treated patients with multiple sclerosis, according to positive or negative status with respect to anti-JC virus antibodies, prior or no prior use of immunosuppressants, and duration of treatment (1 to 24 months vs. 25 to 48 months). Blood samples were available for anti-JC virus antibody testing from 5896 patients with multiple sclerosis and from 54 patients with multiple sclerosis who were treated with natalizumab and in whom PML later developed. RESULTS: As of February 29, 2012, there were 212 confirmed cases of PML among 99,571 patients treated with natalizumab (2.1 cases per 1000 patients). All 54 patients with PML for whom samples were available before the diagnosis were positive for anti-JC virus antibodies. When the risk of PML was stratified according to three risk factors, the risk of PML was lowest among the patients who were negative for anti-JC virus antibodies, with the incidence estimated to be 0.09 cases or less per 1000 patients (95% confidence interval [CI], 0 to 0.48). Patients who were positive for anti-JC virus antibodies, had taken immunosuppressants before the initiation of natalizumab therapy, and had received 25 to 48 months of natalizumab treatment had the highest estimated risk (incidence, 11.1 cases per 1000 patients [95% CI, 8.3 to 14.5]). CONCLUSIONS: Positive status with respect to anti-JC virus antibodies, prior use of immunosuppressants, and increased duration of natalizumab treatment, alone or in combination, were associated with distinct levels of PML risk in natalizumab-treated patients with multiple sclerosis. (Funded by Biogen Idec and Elan Pharmaceuticals.).

Pharmacokinetics of oral tonapofylline and its acyl-glucuronide metabolite in patients with mild and moderate hepatic impairment.

The objective of the study was to evaluate the effect of hepatic impairment on the pharmacokinetics of tonapofylline. Patients with mild or moderate hepatic impairment were enrolled in parallel with demographically matched healthy subjects. All study participants received a single 75-mg oral tonapofylline capsule. The pharmacokinetic parameters for both tonapofylline and its active metabolite, acyl-glucuronide (tonapofylline-AG), were affected by hepatic impairment significantly (P < .1) except for time to peak plasma concentration (t(max)), terminal half-life (t(½)), and apparent volume of distribution based on the terminal phase (Vdz/F). In the mild group, peak plasma concentration (C(max)), area under the time-concentration curve from time 0 to 48 hours postdose (AUC(48 h)), and from time 0 to infinity (AU(Cinf)) of tonapofylline modestly increased as compared with the control healthy subjects (GMR 1.62, 1.57, and 1.53, respectively). The extent of increase of these parameters for tonapofylline-AG was more profound than tonapofylline with geometric mean ratio (GMR) ranging from 2.02 to 2.08. Moderate hepatic impairment was also associated with modest increases of C(max), AUC(48 h), and AUC(inf) of tonapofylline (GMR 1.41, 1.98, and 2.08, respectively). Similar to the mild group, the increase of these parameters were higher for tonapofylline-AG with GMR ranging from 2.80 to 3.86. Single oral 75-mg tonapofylline was safe and well tolerated in patients with mild or moderate hepatic impairment.

Anti-John Cunnigham virus antibody prevalence in multiple sclerosis patients: baseline results of STRATIFY-1.

OBJECTIVE: A study was undertaken to define the prevalence of anti-JC virus (JCV) antibodies in multiple sclerosis (MS) patients and to evaluate the analytical false-negative rate of a 2-step anti-JC virus antibody assay. METHODS: STRATIFY-1 is an ongoing, longitudinal, observational study of relapsing MS patients in the United States who are being treated or considering treatment with natalizumab. Baseline serum and plasma samples were collected for anti-JC virus antibody detection using an analytically validated, 2-step, virus-like particle-based enzyme-linked immunosorbent assay. Urine was collected for JC virus DNA detection. RESULTS: At baseline (n = 1,096), overall anti-JC virus antibody prevalence was 56.0% (95% confidence interval [CI], 53.0-59.0) in STRATIFY-1 patients, with an assay false-negative rate of 2.7% (95% CI, 0.9-6.2). Prevalence was significantly lower in females (53.4%; 95% CI, 49.9-56.8) than males (64.3%; 95% CI, 58.2-70.0) and increased with age, p = 0.0019 and p = 0.0001, respectively. Prevalence was similar in patients regardless of natalizumab exposure or prior immunosuppressant use, p = 0.9709 and p = 0.6632, respectively. STRATIFY-1 results were generally consistent with those observed in another large North American cohort, TYGRIS-US (n = 1,480). INTERPRETATION: Baseline results from STRATIFY-1 are consistent with other studies utilizing this assay that demonstrate a 50 to 60% prevalence of anti-JC virus antibodies, a low false-negative rate, and an association of increasing age and male gender with increasing anti-JC virus antibody prevalence. Neither natalizumab exposure nor prior immunosuppressant use appear to affect prevalence. Longitudinal data from STRATIFY-1 will confirm the stability of anti-JC virus antibody prevalence over time.

Costs and cost-effectiveness of carotid stenting versus endarterectomy for patients at increased surgical risk: results from the SAPPHIRE trial.

OBJECTIVES: To evaluate the cost-effectiveness of carotid stenting vs. carotid endarterectomy using data from the SAPPHIRE trial. BACKGROUND: Carotid stenting with embolic protection has been introduced as an alternative to carotid endarterectomy for prevention of cerebrovascular and cardiovascular events among patients at increased surgical risk. METHODS: Between August 2000 and July 2002, 310 patients with an accepted indication for carotid endarterectomy but at high risk of complications were randomized to and subsequently underwent either carotid stenting (n = 159) or endarterectomy (n = 151). Clinical outcomes, resource use, costs, and quality of life were assessed prospectively for all patients over a 1-year period. Life expectancy, quality-adjusted life expectancy, and health care costs beyond the follow-up period were estimated for patients alive at 1 year, based on observed clinical events during the first year of follow-up. RESULTS: Although initial procedural costs were significantly higher for stenting than for endarterectomy (mean difference: $4,081/patient; 95% CI, $3,849-$4,355), mean post-procedure length of stay was shorter for stenting (1.9 vs. 2.9 days; P < 0.001) with significant associated cost offsets. As a result, initial hospital costs were just $559/patient higher with stenting (95% CI, $3,470 less to $2,289 more). Neither follow-up costs after discharge nor total 1-year costs differed significantly. The incremental cost-effectiveness ratio for stenting compared with endarterectomy was $6,555 per quality-adjusted life year (QALY) gained, with over 98 percent of bootstrap estimates < $50,000/QALY gained. CONCLUSIONS: Although carotid stenting with embolic protection is more costly than carotid endarterectomy, by commonly accepted standards, stenting is an economically attractive alternative to endarterectomy for patients at high surgical risk.