If a crew on a multi-year trip to Mars has to make its own medicine, the drug worth making first is a bone-building osteoporosis shot.
That is the upshot of a ranking published July 9 in npj Microgravity ↗. Researchers led by John Donovan scored 26 peptide drugs on how well each would suit on-demand manufacturing on a long spaceflight. Teriparatide, a fragment of parathyroid hormone sold as Forteo for osteoporosis, came out on top with 17 points out of 20.
Why space needs a pharmacy it can build
A three-year mission cannot pack a three-year supply of temperature-sensitive biologics. Drugs degrade faster in space. Radiation and cramped storage work against shelf life, and resupply from Earth is impossible once a ship is underway. The workaround the field keeps circling is in-situ production. Carry engineered cells and the hardware to grow small batches of a drug on demand, rather than the finished drug itself. Peptides are the first target, because many are short enough to be made by a living cell (recombinant production) instead of assembled by chemistry.
How they scored
Donovan's team rated each of the 26 peptides on two axes, ten criteria in all, each worth zero to two points. The first axis was operational and clinical relevance. It asked whether the drug is approved, how well it stores, and how much it matters for a specific spaceflight health risk, drawing on NASA's own risk roadmap. The second axis was recombinant production feasibility. It asked the manufacturing questions: how long the amino-acid chain is, whether anyone has made it in cells before, how complex the dosing is, and whether it needs post-translational modifications. Those modifications are extra chemical decorations that a simple cell culture cannot easily add.
Teriparatide scored well on both. It is short, it is already produced recombinantly, and it treats a problem astronauts face. Bone loss in microgravity is one of the central hazards of long spaceflight. Crews on the space station shed bone despite hours of daily exercise. Teriparatide is one of the few drugs that builds bone back rather than just slowing its loss. Abaloparatide, a close cousin that hits the same receptor, and amylin, a metabolic hormone, tied for second at 16 points. A cluster at 14 points took in angiotensin II, the antibiotic daptomycin, GLP-1 agonists, and the immune-stimulating factors G-CSF and GM-CSF.
What the ranking is, and is not
This is a feasibility scorecard, not a bioreactor in orbit. Nobody has manufactured teriparatide on a spacecraft, and the paper does not claim otherwise. It ranks candidates against a set of criteria so that whoever builds the first off-world pharmacy has a short list to start from. The scores are judgments applied to public data. A different panel weighting the criteria differently could reshuffle the order.
The exercise surfaces a mismatch. The traits that make a peptide easy to manufacture far from a pharmacy are a short chain, no exotic chemistry, and a cell that can already produce it. Those run almost opposite to what the blockbuster market rewards, where long-acting modified peptides and elaborate formulations win. The drugs best suited to a Mars medicine cabinet are not, mostly, the drugs pulling in the headlines.
Peptidemodel hosts cards for teriparatide ↗ and abaloparatide ↗, both built against the PTH1R target ↗ their bone-building effect runs through, alongside the GLP-1 agonists ↗ that landed a tier lower on the space list.