Here’s an unusual twist for you. Many readers will be familiar – to their regret, most likely – with the story of T*ring Pharmaceuticals (name redacted slightly in order to not defame a great scientist whose name was tacked on to this outfit for no reason other than advertising). Their first idea was to go after praziquantel (PZQ, trade name Biltricide) as a likely acquisition – an old generic drug whose price could be jacked up in order to soak insurance payers. (That one didn’t work out for them, so they went on to do that for pyrimethamine (Daraprim) to great, er, fame).
Praziquantel itself now costs a two to four hundred dollars for a course of therapy in the US, but there are relatively few such courses of therapy here. That’s because it’s mostly used for schistosomiasis and other fluke-worm diseases, which are (thankfully) uncommon here, but these remain real problems in tropical regions, especially where access to clean water is difficult. The WHO estimates that the cost of treatment in sub-Saharan Africa is about $0.30, but the recommendation is for several courses in childhood, given across the at-risk population without individual diagnosis, so that adds up. Repeat treatment of those specifically identified with the infection is also beneficial. Merck Serono donates the drug to the WHO, who send it on to national treatment programs with enough resources to administer it, and USAID also pitches in.
But the cost is still an issue; there are too many people in Africa, South America, and Asia who would benefit, and there are not enough praziquantel doses to treat them with the funding available. Some 250 million people actually suffer from schistosomiasis itself, and the number of people you’d want to treat to keep the disease down is surely far higher than that. That last article article mentions that there are signs of resistance developing as well, which is not good news.
Interestingly, the compound’s mode of action is still somewhat unclear. It appears to disturb calcium ion channels in the worms themselves, and may also interfere with adenosine uptake (none of these species can make their own). As a side chemistry issue, I wrote here about a crowdsourcing project to find a good enantiospecific route to the compound, which is now given as a racemate although it’s the (R) enantiomer that does all the work. That next-to-last link has an interesting finding: one problem with dosing the drug is that it has a particularly bitter and foul taste, but that taste seems to be largely from the inactive enantiomer (!)
So this new paper could be of some interest. The authors, a multicenter team of researchers from the Democratic Republic of the Congo, Belgium, Luxembourg, and just down the road from me at Worcester Polytech, have gone back to an earlier treatment for such worm infections, tea infusions of Artemisia, which is known by the folk name of wormwood for a reason. Two Artemisia species were examined (200 patients for each), with tea give 3 times a day for seven days in comparison to the standard 6-tablet course of praziquantel in another 400 patients. There were some differences between the two tea treatments (particularly between male and female patients), but overall the Artemisia treatment appears to have actually been faster and more effective than praziquantel.
It’s quite reasonable to think that this is due to artemisinin, the well-known natural product from this genus that is also used to treat malaria. The compound was found in the 1980s to be an antihelminthic – in fact, I believe that was the research effort that then discovered its efficacy against the malaria parasites. Artemisinin and related compounds have been tried out in Africa for schistosomiasis, but malaria has been the main focus for the drug. The interesting thing is that only one of the two species used in this trial actually produce artemisinin itself, so there must be other compounds involved. Attempts to use Artemisia tea itself for malaria have not been that successful, with most patients appearing to be underdosed by this route. In this case, though, since the problem is confined to the GI tract and the liver, an oral infusion of this sort directly from the plant would seem to be enough to do the job.
Whether or not this can scale to use in affected areas, I do not know. But the Artemisia species involved are found in these parts of the world, and the hope is that growing and harvesting these could turn into a local industry that could be more beneficial and cost-effective than importing praziquantel. There’s going to be some arguing about the effectiveness of the tea route versus dried-plant tablets, etc., but those are the kinds of things that can be sorted out in real-world practice. For now, this looks like something that could help ease the burden of schistosomiasis and a number of other related diseases that human beings should not have to be infected with, and that’s an excellent thing.