ARROW (thyroid cohorts)
ARROW is the single-arm study behind the second RET inhibitor's thyroid approvals.
ORR 71% in treatment-naive RET-mutant MTC and 60% after prior cabozantinib/vandetanib; 89% in RET-fusion thyroid cancer. Accelerated approval December 2020; the MTC indication was later withdrawn in the US (2023) when the confirmatory trial was not pursued, leaving selpercatinib as the RET-selective option for MTC.
Setting
RET-mutant medullary and RET-fusion thyroid cancer: pralsetinib
Phase
Phase 1/2
Sponsor
Blueprint Medicines
Registry
Headline result
ORR 71% (naive MTC), 89% (RET-fusion thyroid).
Reported
2021
Replication
LIBRETTO-001/531 with selpercatinib show the same RET-selective effect.
In plain words
What these results mean for people, not percentages
Objective response rate, treatment-naive RET-mutant MTCresponse endpoint
- 71 out of 100 people had their tumour shrink with Pralsetinib.
- There was no comparison group, so this number cannot tell you how much of the effect is due to the treatment.
- A response rate counts how many people had their tumours shrink by a set amount; shrinking is encouraging but does not by itself show that people live longer or feel better.
- These results apply to the people the trial enrolled: RET-mutant medullary and RET-fusion thyroid cancer: pralsetinib. People in a different situation may not see the same effect.
- The trial selected people by a biomarker (RET); the result should not be assumed for people whose cancer does not have it.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.