Comparing two natural product Covid proposals
The Herald has a story headlined Pineapples could be key to treating virus about a proposed treatment for early COVID infection. CNN (and various other sources) has a story about oleander extract† as a proposed treatment.
In both cases, the proposal is based on lab studies that have not be formally published, though the oleander one is available as a preprint.
More importantly, though, the Australian pineapple-based treatment is heading into proper clinical trials. In lab tests it has been shown to disable the spike protein that the coronavirus uses for docking to cells. A safety study is about to start, and has an entry in the ANZ clinical trial registry. The treatment isn’t especially dangerous (it’s the enzyme that makes the inside of your mouth sore when you eat raw pineapple) but there’s no good data yet on the exact range of side-effects it is when squirted up your nose on a regular basis. If the side-effects aren’t too bad, the next step will presumably be a controlled trial looking at the effects on the virus, and then a larger controlled trial looking at whether it actually benefits the patients. That’s the usual testing procedure for new treatments.
The US oleander-based treatment† has lab test data showing it stops cells being infected. The manufacturer wants to get the drug into use rapidly, either in controlled trials or, if necessary, by calling it a ‘dietary supplement’† and evading drug approval rules.
In this case, the need for safety studies is obvious. The data on viral replication in the lab looked at concentrations down to 0.05 mg/ml, or 50ng/ml. The lethal† blood concentration has been estimated as 10ng/ml. A previous study of it as a cancer treatment saw ‘dose-limiting toxicities’ at about 2ng/ml — and this is ‘dose-limiting toxicity’ in the context of untreatable cancers, so it has to be pretty brutal.
There will obviously be some low enough dose that’s safe, but there’s currently not the slightest reason to expect those low doses to be effective. You should want lab studies at plausible human doses, and probably animal studies, before you tried giving this to patients, and before you tried advertising it to the President of the United States and the broader public.
† Do not eat/drink/smoke oleander. It will kill you unpleasantly.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »