Onboard a SpaceX flight last week was a remarkable piece of cargo – a hi-tech box destined for the International Space Station to grow ultra-pure protein crystals, with the aim of producing self-injected cancer drugs.

A British startup, BioOrbit, has developed the drug-crystallisation technology at its labs in London and launched Box-E, a compact unit the size of a microwave, on the 15 May rocket from Kennedy Space Center in Florida.

The unit will stay in orbit for about six weeks where the effective weightlessness, or microgravity, enables pharmaceutical compounds to crystallise into pure, highly stable structures that enable drug formulations not achievable on Earth.

Once back on terra firma, these crystals can be turned into cancer medications that patients can keep in a fridge and inject themselves at home or at work, instead of having to go to hospital to have immunotherapies infused intravenously over several hours. The drugs also have a longer shelf life.

Dr Katie King, co-founder and chief executive of BioOrbit, who completed her PhD in nanomedicine at Cambridge University and did an internship at Nasa, describes the orbital tests as a “big step change towards large-scale production of protein crystals in space”. Gravity negatively impacts crystallisation, she says.

“That becomes really critical for protein drugs, antibody drugs because they are very large and very flexible molecules. So through going to space you see a much better, more superior crystallisation process than what you can achieve here on Earth.”

For cancer treatments, a big dose is needed and the liquid can become too thick to use in an injection pen, King says. “Which is why we don’t have these treatments at home already. Through using crystals, you can get these really concentrated formulations that will have a low enough viscosity that they can still flow through the needle.”

Hundreds of experiments onboard the space station have already shown that the process works. Scientists from the US pharma company Merck produced protein crystals for its bestselling cancer medicine Keytruda to turn it into a quick injection instead of a lengthy IV infusion. This new route of delivery was approved by the US health regulator in September.

“Box-E is the first step moving towards mass manufacture in a way that will transform cancer treatment, reduce hospital visits and support patients in receiving therapies at home,” says King, who is the daughter of the TV presenter and maths whiz Carol Vorderman.

Despite the huge expense of sending the drugs into space, King argues the switch to self-injection at home could end up saving the NHS and other health systems “millions, potentially billions” of pounds.

Assuming the orbital tests are successful, multiple Box-E units could be stacked together to ramp up the pace of pharmaceutical manufacturing in space. BioOrbit is aiming to process thousands of litres of fluid per box every year, and is confident it could produce enough for a blockbuster drug with a handful of boxes in constant use.

Last month BioOrbit, founded in 2023 by King and the medical doctor and cancer researcher Leonor Teles, raised £9.8m from investors, led by the UK venture capital group LocalGlobe and Paris-based VC firm Breega, to take its technology into orbit and build the hardware to mass produce crystals.

BioOrbit won a £250,000 contract from the UK’s Space Agency in March to manufacture drugs in microgravity.

This week Elon Musk’s SpaceX set out its stock market flotation prospectus, which mentions in-space manufacturing of pharmaceuticals and other materials as a key revenue stream, and estimates a $22.7tn market in enterprise applications. BioOrbit wants to be part of that.

However, King says it will take at least five years until the new cancer drug formulations hit the market, as they need to be tested in clinical trials and get approved by health regulators.

She adds that the crystallisation technology can also be used for other treatments. About 70% of the world’s biggest-selling drugs are administered intravenously at hospitals or doctor’s offices.

To make its cancer drugs, BioOrbit will partner up with pharmaceutical companies, and has already had interest from several multinational groups, including in the UK and the US.

The Californian startup Varda Space Industries has also flown small capsules into space to process pharmaceuticals, and is working with the US biotech United Therapeutics Corporation to develop improved treatments for rare lung disease.