Varda tests cancer-drug crystallisation in space
W-7 is Varda's third launch and fourth of 2026 (image: Varda)
Before a solid medicine can be absorbed, its active ingredient generally needs to dissolve. For some promising cancer-drug compounds, achieving predictable dissolution is a formulation challenge, tied partly to how their molecules assemble into solid material.
Varda Space Industries, a California company developing spacecraft for pharmaceutical processing and re-entry, is investigating that problem in orbit. Its W-7 mission launched on 20 October 2026 carrying an experiment on a compound belonging to a class known as PROTACs. The company is exploring whether microgravity can produce crystalline material with properties that make these complex molecules easier to formulate into medicines.
How PROTAC cancer drugs recruit the cell’s disposal machinery
PROTAC stands for proteolysis-targeting chimera. These molecules bring a chosen protein together with an enzyme called an E3 ubiquitin ligase. This enables the target to be tagged with ubiquitin, a molecular signal directing it to the proteasome, the cell’s protein-breakdown machinery.
The approach gives drug developers a way to remove proteins involved in disease. For example, the US National Cancer Institute describes how the PROTAC compound vepdegestrant recruits this machinery to break down oestrogen receptors, which can support the growth of certain cancers.
Bringing the target and disposal machinery together requires several connected molecular components. Varda says these relatively large, complex compounds can be difficult to formulate because their crystallinity can be poor or inconsistent, complicating both dissolution and subsequent manufacturing. Controlling the solid material is therefore an important part of developing a usable medicine.
Why drug crystals matter for formulation and manufacturing
Crystallisation arranges molecules into an ordered solid. The resulting structure and particle characteristics influence how pharmaceutical material behaves during production and use, including how it dissolves. Different crystalline arrangements of the same substance, known as polymorphs, can have different properties even though the underlying drug molecule remains unchanged.
For a manufacturer, obtaining a useful crystal form is one part of the task; producing it consistently is another. Small seed crystals can provide a starting structure on which more dissolved molecules assemble, helping initiate the growth of a selected crystalline form.
Speaking to Axios, Varda chief strategy officer Michael Reilly described producing seed quantities in space that could subsequently be propagated on Earth. In that approach, a small orbital batch could help start a larger manufacturing process on the ground. This would concentrate orbital processing on obtaining useful seed material while allowing further crystal growth to take place in terrestrial facilities.
How microgravity changes drug crystallisation
Microgravity offers a way to change the conditions under which those initial crystals form. On Earth, particles settle under gravity, while density differences can drive currents within liquids. These processes affect the supply of molecules to growing crystals and the conditions around them.
In orbit, the spacecraft and its contents remain in continuous free fall around Earth, creating microgravity. Sedimentation and buoyancy-driven convection are greatly reduced, allowing researchers to investigate crystallisation under different physical conditions.
Pharmaceutical research aboard the International Space Station has already shown how this can inform processing on Earth. In a study published in npj Microgravity in 2019, researchers from MSD, the pharmaceutical company also known as Merck & Co., and collaborators investigated pembrolizumab, the antibody medicine marketed as Keytruda.
Their space-grown crystalline suspensions had a more uniform particle-size distribution and lower viscosity than comparable ground samples. The researchers then used the findings to develop terrestrial crystallisation methods, applying mixing and temperature control to produce uniform suspensions with properties suitable for investigating injectable formulations.
The antibody study illustrates a complementary route to the seed-crystal approach: using orbital experiments to identify processing methods that can subsequently be reproduced on Earth.
How Varda returns pharmaceutical material to Earth
To study material processed in orbit, researchers also need a reliable way to recover it. Varda’s free-flying W-series platform operates independently of a space station, carrying automated equipment that can heat, mix and cool pharmaceutical material without astronauts. After orbital operations, a return capsule separates from the spacecraft, enters the atmosphere behind a protective heat shield and descends by parachute for recovery.
For pharmaceutical research, recovery also means preserving the material’s physical form through the stresses of spaceflight and atmospheric re-entry.
Varda and its collaborators have already demonstrated this with ritonavir, an antiviral medicine. A study made available as a ChemRxiv preprint reported successful recovery of Form III generated in orbit, a metastable crystal form that can persist under suitable conditions despite another form being more stable. Samples representing other physical forms of ritonavir also showed strong stability.
The researchers examined stability against factors including vibration, acceleration, radiation and temperature. Recovering the orbital material in its intended form demonstrated that the return journey could preserve the output of pharmaceutical processing for analysis on Earth.
Varda’s collaboration with United Therapeutics
Varda is applying that capability beyond its ritonavir work. Alongside W-7, it is collaborating with United Therapeutics, a US biotechnology company developing treatments for rare pulmonary disease. Announced in May 2026, the partnership envisages multiple missions processing small-molecule medicines, exploring formulations with improved stability, absorption or delivery characteristics.
This gives Varda a pharmaceutical collaboration through which to apply its spacecraft and processing capabilities to specific formulation objectives. The work brings together its orbital engineering with United Therapeutics’ expertise in drug development.
For W-7, the opportunity is to give developers of protein-degrading cancer medicines another way to obtain useful crystalline material. If suitable crystals can seed further growth on Earth, a small orbital batch could support a much larger production process, making space one specialised stage in manufacturing medicines for patients on the ground.
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