Como dizer "Em fase de teste(s)" em inglês

Português: em fase de teste, sendo testado para se saber se funciona, é seguro, etc.
Inglês: undergoing trials

Trial: a process of testing to find out whether something works effectively and is safe. - Longman

Exemplos:

1. ''Called the Cognition System, the high-tech hairnet is undergoing trials in the U.S. If these prove successful, the device could be tested in the...''
2. A new class of anticancer drug is undergoing trials in the UK and the USA, the UK Institute of Cancer Resea-rch has announced.
3. The device is undergoing trials at the Oklahoma University Health Sciences Center as part of the FDA 510(k) clearance process.
4. Microcapsule delivery systems developed in part through data provided by previous Shuttle research missions have been patented and are undergoing trials.