Legacy modernisation for a pharma manufacturer

The client is a Swiss pharmaceutical manufacturer running a validated legacy system at the heart of GxP-regulated operations. In pharma, any change to a validated computerised system triggers revalidation, which makes even small updates slow and expensive.

The business needed to move faster and modernise its technology, but could not accept any approach that left the system, even briefly, in an unvalidated state.

A validated legacy core made every change slow and risky, because touching a GxP-regulated system means revalidation, not just a deploy. The regulatory overhead turned routine improvements into major undertakings.

A full rewrite was off the table: the revalidation burden and business risk of replacing the whole system at once were simply too high. The safe-looking option of 'start again' was in fact the riskiest.

The manufacturer needed to modernise incrementally without ever leaving the system in an unvalidated state. Continuous compliance was a hard constraint that shaped the entire approach.

We applied the strangler-fig pattern, carving capabilities out into services behind a stable interface so the legacy core kept running throughout. Nothing was switched off until its replacement was proven, so the system stayed live and compliant the whole way.

Each new service was validated before it took traffic, and legacy modules were retired only once the replacement was proven in a parallel run. That kept the system continuously validated rather than gambling on a cutover.

We prioritised the modules where change friction was costing the business most, so the earliest work delivered the biggest reduction in day-to-day pain. Value landed early rather than at the end of a long programme.