You will be provided with the titles and abstracts of a collection of medical RCT reports studying a clinical question -- for instance, the efficacy of an intervention on some medical outcome. Please write a few sentences synthesizing the findings of these reports, which could serve as a conclusion section for a systematic review article. Your response should not include any other text. The RCT reports are below.



Title 1:
Herbal medicines in migraine prevention Randomized double-blind placebo-controlled crossover trial of a feverfew preparation.
Abstract 1:
The efficacy of feverfew capsules on migraine prophylaxis was investigated in a randomized double-blind, placebo-controlled crossover study in which 50 patients, who had not used feverfew before, participated. The capsules were filled with a dried alcoholic extract of feverfew on microcristalline cellulose and contained 0.5 mg parthenolide. The patients used one capsule (feverfew or placebo) a day. Fourty four patients completed the 9 month study. Both treatment groups suffered the same number of migraine attacks. A prophylactic effect could not be demonstrated for our feverfew preparation, but the patients seemed to have a tendency to use fever symptomatic drugs during the period they used feverfew. This result was not in accordance with the results from two other studies. The difference may be explained by the fact that both other studies included patients who previously reported positive experiences with feverfew preparations for migraine prophylaxis.
                Copyright © 1996 Gustav Fischer Verlag · Stuttgart · Jena · New York. Published by Elsevier GmbH.. All rights reserved.


Title 2:
The efficacy and safety of Tanacetum parthenium (feverfew) in migraine prophylaxis--a double-blind, multicentre, randomized placebo-controlled dose-response study.
Abstract 2:
Tanacetum parthenium (feverfew), is a well-known herb for the prophylactic treatment of migraine. The primary objective was to show a dose-response of a new stable extract (MIG-99) reproducibly manufactured with supercritical CO2 from feverfew (T. parthenium). Furthermore, the study should provide data on the safety and tolerability of MIG-99. In a randomized, double-blind, multicentre, controlled trial with an adaptive design, the clinical efficacy and safety of three dosages of MIG-99 (2.08 mg; 6.25 mg; 18.75 mg t.i.d.) were compared with placebo. The patients (n = 147) suffered from migraine with and without aura according to International Headache Society (IHS) criteria and were treated with one of the study medications for 12 weeks after a 4-week baseline period. The primary efficacy parameter was the number of migraine attacks during the last 28 days of the treatment period compared with baseline. Secondary endpoints were total and average duration and intensity of migraine attacks, mean duration of the single attack, number of days with accompanying migraine symptoms, number of days with inability to work due to migraine as well as type and amount of additionally taken medications for the treatment of migraine attacks. The design of the study included a pre-planned adaptive interim analysis for patients with at least four migraine attacks within the baseline period. With respect to the primary and secondary efficacy parameter, a statistically significant difference was not found between the overall and the confirmatory intention-to-treat (ITT) sample in the exploratorily analysed four treatment groups. The frequency of migraine attacks for the predefined confirmatory subgroup of patients (n = 49) with at least four migraine attacks during the baseline period decreased in a dose-dependent manner (P = 0.001). The highest absolute change of migraine attacks was observed under treatment with 6.25 mg t.i.d. (mean +/- SD = -1.8 +/- 1.5 per 28 days) compared with placebo (-0.3 +/- 1.9; P = 0.02). Overall, 52 of 147 (35%) patients reported at least one adverse event (AE). The incidence of AEs in the active treatment groups was similar to that in the placebo group, and no dose-related effect was observed in any safety parameter. MIG-99 failed to show a significant migraine prophylactic effect in general. Accordingly, in the ITT analysis a dose-response relationship could not be observed. MIG-99 was shown to be effective only in a small predefined subgroup of patients with at least four attacks during the 28-day baseline period where the most favourable benefit-risk ratio was observed with a dosage of three capsules of 6.25 mg MIG-99 extract per day. Because of the low number of patients, these findings need to be verified in a larger sample. The incidence of AEs was similar for all treatment groups.


Title 3:
Efficacy of feverfew as prophylactic treatment of migraine.
Abstract 3:
Seventeen patients who ate fresh leaves of feverfew daily as prophylaxis against migraine participated in a double blind placebo controlled trial of the herb: eight patients received capsules containing freeze dried feverfew powder and nine placebo. Those who received placebo had a significant increase in the frequency and severity of headache, nausea, and vomiting with the emergence of untoward effects during the early months of treatment. The group given capsules of feverfew showed no change in the frequency or severity of symptoms of migraine. This provides evidence that feverfew taken prophylactically prevents attacks of migraine, and confirmatory studies are now indicated, preferably with a formulation controlled for sesquiterpene lactone content, in migraine sufferers who have never treated themselves with this herb.
There is insufficient evidence from randomised, double-blind trials to suggest an effect of feverfew over and above placebo for preventing migraine. It appears from the data reviewed that feverfew presents no major safety problems.