Fulranumab in Patients With Pain Associated With Postherpetic Neuralgia and Postraumatic Neuropathy: Efficacy, Safety, and Tolerability Results From a Randomized, Double-blind, Placebo-controlled, Phase-2 Study.

OBJECTIVE: Fulranumab is an antibody that specifically neutralizes the biological activity of human nerve growth factor. This multicenter, phase-2, randomized, double-blind (DB), placebo-controlled study evaluated the analgesic efficacy and safety of fulranumab in postherpetic neuralgia (PHN) and posttraumatic neuropathy (PTN) patients. METHODS: Patients (18 to 80 y) with inadequately controlled moderate-to-severe pain received study medication (subcutaneous injection) every 4 weeks. PHN patients were randomized (3:2:2:3) to receive either placebo or one of 3 doses of fulranumab: 1 mg (1 mgQ4 wk), 3 mg (3 mgQ4 wk), or 10 mg (10 mgQ4 wk). PTN patients were randomized (1:1) to receive either placebo or fulranumab 10 mgQ4 wk. RESULTS: The US Food and Drug Administration placed a clinical hold (December 23, 2010) on all trials of antinerve growth factor drugs, including fulranumab, due to identified risks of osteonecrosis or rapidly progressing osteoarthritis; therefore, only 49 (of 150 planned) PHN patients and 34 (of 50 planned) PTN patients completed the DB efficacy evaluation. There was no significant difference (P>0.05, fulranumab vs. placebo) for change in 7-day average of daily pain intensity scores from DB baseline to end of 12-week DB efficacy phase in PHN or PTN patients (primary endpoint). No significant difference was found with fulranumab versus placebo (P>0.05) in other efficacy measures in either PHN or PTN patients. The most common treatment-emergent adverse events (>10% incidence) in PTN patients were sinusitis, carpal tunnel syndrome, and headache, whereas in PHN patients it was arthralgia. DISCUSSION: Fulranumab did not demonstrate efficacy in either PHN or PTN patients, but was generally well-tolerated in this small underpowered and abbreviated study.

Fulranumab for treatment of diabetic peripheral neuropathic pain: A randomized controlled trial.

OBJECTIVE: To assess efficacy and safety of fulranumab, a fully human monoclonal antibody against nerve growth factor, in patients with diabetic peripheral neuropathic pain (DPNP). METHODS: In this phase II, double-blind, placebo-controlled trial, patients with moderate to severe DPNP were randomized to treatments with fulranumab (1, 3, or 10 mg) or placebo administered subcutaneously every 4 weeks. RESULTS: Because of early study termination (clinical hold) by the US Food and Drug Administration, 77 (intent-to-treat) of the planned 200 patients were enrolled. The primary endpoint, the mean reduction of average daily pain at week 12 compared with baseline, showed a positive dose-response relationship (p = 0.014, 1-sided); the pair-wise comparison between the 10-mg group and placebo was significant (unadjusted p = 0.040, 2-sided). An exploratory responder analysis revealed that a greater proportion of patients in the 10-mg group reported ≥30% reduction in the average DPNP intensity compared with placebo at week 12 (p = 0.006). Although not statistically significant, several secondary endpoints showed directionally similar results to the primary efficacy dose-response relationship. During the combined efficacy and safety extension phases, the top 3 treatment-emergent adverse events in the combined fulranumab group were arthralgia (11%), edema peripheral (11%), and diarrhea (9%). No cases of joint replacement or death were reported. CONCLUSION: Despite early study termination, fulranumab treatment resulted in dose-dependent efficacy and was generally well tolerated. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in patients with DPNP, fulranumab 10 mg reduces pain by 1.2 points on an 11-point scale compared with placebo.

Double-blind crossover study to assess potential differences in cytochrome P450 3A4 activity in healthy subjects receiving ondansetron plus dexamethasone, with and without aprepitant.

PURPOSE: Because glucocorticoids and the neurokinin-1 receptor antagonist aprepitant influence CYP3A4 activity, this study assessed whether aprepitant added to a 5-HT(3) antagonist and glucocorticoid would affect CYP3A4 induction. METHODS: In this double-blind, 2-period crossover study, 12 subjects were randomized to receive a triple regimen (oral aprepitant [A] 125 mg, intravenous ondansetron [O] 32 mg, and oral dexamethasone [D] 12 mg day 1; A 80 mg and D 8 mg days 2-3; D 8 mg day 4) in 1 of 2 periods, and a dual regimen (O 32 mg and D 20 mg day 1; D 8 mg bid days 2-4); the D dose was adjusted to account for known dexamethasone/aprepitant interaction. Oral (2 mg) and intravenous (1 mg) stable isotope ((13)C(5) (15)N(1))-labeled midazolam were simultaneously given as probes on days -1, 6, 8, 15, and 22 of each period. If the a priori 90% confidence interval for the day 6 geometric mean oral midazolam AUC(0-∞) ratio (triple/dual regimen) of fold-change from baseline was above 0.5, it would be concluded that there was no clinically meaningful between-regimen difference in CYP3A4 activity. RESULTS: Day 6 oral midazolam AUC(0-∞) geometric mean fold-change from baseline was 0.84 (0.30-1.58 with A, 0.46-1.69 without A). The ratio of geometric mean oral midazolam AUC(0-∞) fold-changes was 1.00 (90% confidence interval 0.80, 1.25). CONCLUSIONS: Aprepitant plus a 5-HT(3) antagonist and dexamethasone is unlikely to have a significant additional inductive effect on CYP3A4 activity beyond that of the dual regimen.

Lack of effect of aprepitant on the pharmacokinetics of docetaxel in cancer patients.

BACKGROUND: Aprepitant is a selective neurokinin-1 receptor antagonist that is effective for the prevention of nausea and vomiting caused by highly emetogenic chemotherapy. In vitro, aprepitant is a moderate inhibitor of the CYP3A4 enzyme, which is involved in the clearance of several chemotherapeutic agents. In this study we examined the potential for aprepitant to affect the pharmacokinetics and toxicity of intravenously administered docetaxel, a chemotherapeutic agent that is primarily metabolized by CYP3A4. METHODS: A total of 11 cancer patients (4 male, 7 female, aged 50-68 years) were enrolled in this multicenter, randomized, open-label, two-period, crossover study. Patients received a single infusion of docetaxel monotherapy, 60-100 mg/m(2), on two occasions at least 3 weeks apart. During one of the cycles (treatment A), patients received docetaxel alone. During the alternate cycle (treatment B), they also received aprepitant 125 mg orally 1 h prior to docetaxel infusion (day 1), and a single oral dose of aprepitant 80 mg on days 2 and 3. The pharmacokinetic profile of docetaxel was assessed over 30 h following docetaxel infusion. Blood counts were monitored on days 1, 4, 7, and 14. RESULTS: Ten patients completed the study. Concomitant administration of aprepitant did not cause any statistically or clinically significant changes in docetaxel pharmacokinetics. Values for docetaxel alone (treatment A) versus docetaxel with aprepitant (treatment B) were as follows: geometric mean AUC(0-last) was 3.26 vs 3.17 microg h/ml (P>0.25; ratio B/A 0.97); geometric mean AUC(0-infinity) 3.51 vs 3.39 microg h/ml (P>0.25; ratio B/A 0.96); geometric mean C(max) was 3.53 vs 3.37 microg/ml (P>0.25; ratio B/A 0.95); and geometric mean plasma clearance was 23.3 vs 24.2 l/h/m(2) (P>0.25; ratio B/A 1.04). The corresponding harmonic mean half-life values were 10.1 and 8.5 h. The two treatment regimens had similar tolerability profiles; the median absolute neutrophil count nadirs were 681/mm(3) during treatment with docetaxel alone and 975/mm(3) during aprepitant coadministration. CONCLUSIONS: Aprepitant had no clinically significant effect on either the pharmacokinetics or toxicity of standard doses of docetaxel in cancer patients. Aprepitant at clinically recommended doses may have a low potential to affect the pharmacokinetics of intravenous chemotherapeutic agents metabolized by CYP3A4.