For patients with RET-fusion+ NSCLC who progress on RET inhibitors, do you repeat tumor molecular profiling before selecting subsequent therapy?  

Yes, I repeat molecular profiling, ideally with both repeat tissue and liquid biopsy.

I think it's always important to know a tumor's genotype after progression on a targeted agent, because of emerging literature of the effectiveness of TKIs based on the resistance mechanism.  However, in SOC practice, there is no validated approach to sequencing RET TKIs based on the genomics o...

At our institution, we obtain both liquid and tissue biopsy if feasible and repeat molecular profiling to determine mechanism of acquired resistance that may be amenable to other targeted therapy approaches, including evaluation for suitable clinical trials.

If patient is willing, another biopsy (tissue and/or liquid) for next gen sequencing may give insight to understand the mechanism of resistance to RET TKI that could be helpful to select next line of therapy and clinical trial.

I routinely do - though, I would not consider it standard as the information is unlikely to guide therapy. There are trials where knowing whether RET point mutations are present could guide eligibility - and it is increasingly possible to enroll on these trials remotely. We have seen off target resi...