Genital warts - sinecatechins
Many of the most familiar pharmaceutical medicines were originally extracted from natural sources such as plants and algae, and many more are modified versions of these chemical extracts. However, few herbal medicines have had formal clinical trials that prove they work, relying on folklore and word of mouth.
Many of the most familiar pharmaceutical medicines were originally extracted from natural sources such as plants and algae, and many more are modified versions of these chemical extracts. However, few herbal medicines have had formal clinical trials that prove they work, relying on folklore and word of mouth.
One plant extract that is currently undergoing clinical trials is a polyphenols extract from green tea. It is being tested to show its effectiveness as a treatment for genital warts, which are caused by the human papilloma virus. It is sold under the brand names Veregen and Polyphenon E by German company MediGene, and the extract itself is made by Japanese company Mitsui Norin.
Extracted from the low caffeine green tea Camellia sinensis, by far the largest component of the product by weight is a group of chemicals called catechins. It also contains small amounts of other ingredients, including caffeine, theobromine and gallic acid. It has been approved for the topical treatment of genital warts in the US for a couple of years. Its mode of action is unknown, but MediGene believes that it is able to penetrate the skin and has immunomodulatory effects, as well as acting on the infected cells themselves, where they have effects on cytokines and interferons. Several clinical trials have now taken place.
A randomised, double blind, vehicle controlled trial was carried out in 502 male and female patients aged 18 or over who had between 2 and 30 anogenital warts, with a total wart area ranging from 12 to 600mm.1 Patients applied the ointment, either 10% or 15%, or a vehicle without the sinecatechins, three times a day for a maximum of 16 weeks, or until complete clearance of all warts, followed by a 12 week treatment-free follow-up to assess recurrence. A total of 57% of those who used the 15% ointment and 56% of those using the 10% ointment experienced complete clearance of all baseline and newly occurring warts. This compares with just 34% of those who used the vehicle alone. They were least likely to recur in the group who used the stronger ointment.
A similar regimen was used in a second clinical trial, this time in 503 patients with anogenital warts.2 This time, 53% using the stronger ointment and 51% of those using the 10% product found that all their warts cleared up during the trial period, compared with 37% who used the vehicle. A better response was seen in women than men - 60% of women and 45% of men across both groups given active ointment achieved complete clearance of all warts. In total, 78% of all those using either strength of active ointment showed wart clearance rates of at least 50%. Recurrence rates during the follow-up period were below 6%.