What the phases mean:
- Phase 1a: First-in-human testing. The primary goal is safety: "Is this drug safe in humans at all?" A small group of patients receives escalating doses to find the maximum tolerated dose.
- Phase 1b: Expansion phase. Now that safety is established, more patients receive the drug to gather preliminary efficacy data.
- Phase 2: Larger group testing efficacy and further safety.
- Phase 3: Large-scale comparison against the current standard of care.
- Phase 4: Post-approval monitoring.
MCHS context: AL-605 is in Phase 1a/b, which means it's still in early stages and primarily about safety and dose-finding. The fact that it's reaching patients at all is a milestone, but results are still preliminary. For MCHS specifically, the CDK2 inhibitor would need to be repurposed (used for a different condition than originally designed), meaning we'd need convincing preclinical data before a neuroinflammation trial could launch.