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Anthony W Fox

Publications and source records attributed to Anthony W Fox.

6 recordsLinked to original sources
PubMed2002

Evidence-based assessment of pregnancy outcome after sumatriptan exposure.

OBJECTIVE: Assessment of best available evidence for tolerability of sumatriptan after inadvertent exposure during pregnancy. BACKGROUND: Migraine's demography suggests that inadvertent exposure to acute therapies is likely during the earliest undiagnosed stages of pregnancy. The tolerability of such therapies under these conditions is not amenable to clinical trial for ethical reasons. In the United States, sumatriptan is currently labeled pregnancy category C (ie, not recommended for use during pregnancy unless the potential benefit justifies the potential risk to the fetus). METHODS: Three types of adverse events were studied: spontaneous abortion, fetal abnormality, and obstetric complications. Traditional evidence-based criteria were used to assess a search-protocol product of four clinical studies and two case reports. RESULTS: The single positive finding ("preterm delivery" without low birth weight) was in the smallest study; this study was retrospective and the finding was externally inconsistent with the other three larger studies, all of which were prospective. No study followed children for more than 4 years, which is the period needed to identify the maximum number of congenital anomalies. Rigorous teratological technique was generally not employed. Post hoc power calculations were used to provide parameters of the hazard detectable by these studies in aggregate. CONCLUSIONS: Pregnancy categories B and C both seem feasible for sumatriptan. Within the limits of the examined studies, there is no evidence for any specific effect of sumatriptan on pregnancy outcome. Patients inadvertently exposed to sumatriptan during an early stage of pregnancy should be reassured by these data.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Comparison of therapeutic gain with therapeutic ratio for the assessment of selective 5HT(1B/1D) agonist efficacy in migraine.

OBJECTIVE: Comparison of use of therapeutic gain (TG) and therapeutic ratio (TR) for relative assessments of selective 5HT(1B/1D) agonist efficacy in the acute treatment of migraine. BACKGROUND: Comparison of selective 5HT(1B/1D) agonist efficacy in the acute treatment of migraine is complicated by the impracticality of conducting high-quality head-to-head active comparator trials for all permutations of drug, dose, and route of administration; the clinical trials that are available are usually noncontemporaneous, and have fluctuating active and placebo response rates (ARR and PRR, respectively) for the necessarily subjective endpoints. The standard primary endpoint is conversion of headache score 2 (moderate pain) or score 3 (severe pain) into score 0 (no pain) or score 1 (mild pain) at a single timepoint (usually 2 or 4 hours postdose). Two principal methods have been used for comparison of ARR between studies: TG = ARR - PRR and TR = ARR/PRR. Secondary endpoints can be treated in the same way, although the 24-hour remedication rate is the only secondary endpoint that is subject to regulatory authority standardization. Does either TG or TR have an advantage over the other? METHODS: Efficacy data were collected from published sources and included pain score conversion at 2- and 4-hour, as well as 24-hour remedication rates. TG and TR were calculated for each endpoint, as shown above. The ranges of these variables were found from all observed measures. Correlations between TG and TR were found using least squares methods. The 95% confidence intervals (CI) for TG and TR were then found for all clinical trials, and for the whole range of observed PRR. RESULTS: Values for TR and TG generally were well correlated for pain score conversion at 2 hours postdose (n = 51 clinical trials). Deviations from this correlation were greatest for drugs that were evidently very efficacious. When standardized for the observed ranges of PRR and ARR, the 95% CI for TR were narrower than for TG. A subset of these studies also reported 4-hour data (n = 23 clinical trials), but the correlation between TR and TG was again good, with narrower 95% CI for TR than TG. For the 24-hour remedication data (n = 18 trials), PRR was less variable; TR and TG again correlated well, but there was little difference in their relative 95% CI. CONCLUSIONS: For comparison of drugs in noncontemporaneous studies, when PRR fluctuates, relative ranges for TR are narrower than for TG. For assessing single clinical trial results (ie, point estimates of efficacy) TR will generally be relatively nearer to its mean than TG. For both these reasons, TR is a more robust statistic than TG.

Acute Disease↗