ChEMBL lists various properties at pages for substances. I would like to copy some of the data that resides under "Max phase for indication" over to Wikidata. For that it would be good to know the exact definition that ChEMBL uses for "Max phase for indication". Unfortunately I can't find it on their website. Is a definition available somewhere?
This refers to the phase a compound has "achieved" in a clinical trial.
Phases are typically ordered from 1 to 4 (although phases 1-3 are most talked about, as they are needed to bring a drug to market):
Phase 1: Testing of drug on healthy volunteers for dose-ranging
Phase 2: Initial testing of drug on patients to assess efficacy and safety
Phase 3: Testing of drug on patients to assess efficacy, effectiveness and safety (larger test group)
Finally, there is Phase 4 (referred to in your example), which is after a drug has been approved (by e.g. the FDA or the EMEA): here, the effects of a drug while used on the general patient population are monitored.
Your example has been approved (i.e. it can be brought to market, or might already be available), while others might still be in ongoing clinical trials. Others might have been "killed" earlier due to e.g. toxicity or side effects. Or have not even entered clinical trials (which would be the majority of compounds).