I would like to quote this comment from an earlier discussion on HN: https://news.ycombinator.com/item?id=39544442.

> Perfect crystals. Also, the proof-of-concept drug was ritonavir, and it's nearly impossible to consistently grow large crystals of it on Earth. All of the labs that work with ritonavir are contaminated by a more stable form ("polymorph") that rapidly converts any ritonavir crystals into a less-useful form.

In short: yes, you're correct, but I am just parroting somebody else; personally, I posses no actual knowledge of chemistry involved.