Lung & Respiratory Care

Biography

Biography: Stephan Koelsch

Abstract

Iota-carrageenan (I-C) is active against respiratory viruses in vitro and was effective as nasal spray in three clinical trials with common cold patients. To further investigate I C, a fourth randomized, placebo-controlled, double-blind clinical trial was conducted in 200 adult patients with self-diagnosed colds that were confirmed by baseline symptom scores. Respiratory viruses were quantified at baseline and on treatment day 3 or 4. Primary endpoint was the mean total symptom score of 8 cold symptoms on Days 2 to 4. The primary endpoint did not demonstrate a statistically significant difference between I-C and placebo but showed a trend towards I-C benefit. Exploratory analyses indicated significant reduction of cold symptoms in the I-C group and also substantiated I-C’s activity against rhinovirus. To observe trends rather than statistically significant outcomes obviously was based on an unexpected low power of the trial. In particular, the proportion of virus-positive patients was smaller than anticipated. Only 23.6% had rhinovirus in contrast to 50-90% in other studies. This low frequency of rhinovirus-positive patients in the ICICC study demonstrates that there may often be a trade-off when the standard design for cold studies is used. When a controlled study tries to recruit patients at the earliest stages of a cold, patients may incorrectly believe they are coming down with a cold, prior to full blown cold symptoms. Hence, the peculiarities of the ICICC study may trigger a discussion among the scientific community about more suitable study designs to investigate common cold treatments.