A Study of Selpercatinib (LY3527723) in Participants With RET-Mutant Medullary Thyroid Cancer

PFS is defined as the time from randomization until the occurrence of documented disease progression by the BICR, per Response Evaluation Criteria in Solid Tumors (RECIST 1.1) criteria, or death from any cause in the absence of BICR-documented progressive disease. Progressive Disease (PD) was at least a 20% increase in the sum of the diameters of target lesions, with reference being the smallest sum and an absolute increase of at least 5 mm, or unequivocal progression of non-target lesions, or 1 or more new lesions.

Time frame: Baseline to Progressive Disease or Death from Any Cause, Whichever Occurs First, Up to 39 Months

Population: All randomized participants, even if a participant did not take the assigned treatment, did not receive the correct treatment, or otherwise did not follow the protocol. Censored participants: Selpercatinib - 167; Cabozantinib or Vandetanib - 66

Comparative tolerability defined as a comparison of the proportion of time on treatment with high side effect bother as assessed by the FACT-GP5. The FACT-GP5 is a single question used to assess the overall bother of the treatment side effects. It is scored using a 5-point rating scale (0 = not at all; 1 = a little bit; 2 = somewhat; 3 = quite a bit; and 4 = very much), where lower scores reflect less bother from treatment side effects. Time with high side effect bother (i.e.) score of 3 or 4 is reported here and was derived as follows: cumulative amount of time, in weeks, during which a participant reports high side effect bother divided by the total duration of therapy (weeks), derived as (date of last study treatment dose - date of first study treatment dose + 1) divided by 7.

Time frame: Baseline to Progressive Disease, Unacceptable Toxicity or Death from Any Cause Up to 39 Months

Population: All participants who received the first dose of study treatment prior to the interim efficacy analysis and at least 6 months prior to the data cutoff date. Analysis of tolerability will be based on the actual treatment a participant received on the first study treatment administration regardless of which treatment they were randomized to receive (as treated).

DoR by BICR is defined as the time from the date that measurement criteria for complete response (CR) or partial response (PR) (whichever is first recorded) are first met by the BICR or investigator assessment, as applicable, until the first date that disease is recurrent or documented disease progression is observed, per RECIST 1.1 criteria, or the date of death from any cause in the absence of documented disease progression or recurrence. Progressive Disease (PD) was at least a 20% increase in the sum of the diameters of target lesions, with reference being the smallest sum and an absolute increase of at least 5 mm, or unequivocal progression of non-target lesions, or 1 or more new lesions.

Time frame: Date of CR or PR to Date of Disease Progression or Death Due to Any Cause Up to 39 Months

Population: All randomized participants, even if a participant did not take the assigned treatment, did not receive the correct treatment, or otherwise did not follow the protocol. Censored participants: Selpercatinib - 119, Cabozantinib or Vandetanib - 25

ORR is defined as the number of participants who achieved the best overall response (BOR) of CR or PR divided by the total number of participants randomized to each treatment arm. ORR per RECIST 1.1 as assessed by BICR.

Time frame: Baseline through Disease Progression or Death Up to 39 Months

Population: All randomized participants, even if a participant did not take the assigned treatment, did not receive the correct treatment, or otherwise did not follow the protocol.

Overall survival (OS) is defined as the time from randomization until death from any cause. If the participant is alive or lost to follow-up at the time of data analysis, OS data will be censored on the last date the participant is known to be alive.

Time frame: Baseline

Progression-free survival 2 (PFS2) is defined as the time from randomization to disease progression (radiographic or symptomatic progression as determined by the investigator) on the next line of treatment or death from any cause in the absence of observed disease progression. If the participant is alive at the cutoff for analysis, and disease progression has not been observed, PFS2 data will be censored on the latest date of last progression-free assessment or start of the next line of treatment.

Time frame: Baseline

Time frame: Baseline

TFFS by BICR is defined as the time from randomization to the first occurrence of: * documented radiographic disease progression per RECIST 1.1 as assessed by BICR; or * unacceptable toxicity leading to treatment discontinuation as assessed by the investigator. Progressive Disease (PD) was at least a 20% increase in the sum of the diameters of target lesions, with reference being the smallest sum on study and an absolute increase of at least 5 mm, or unequivocal progression of non-target lesions, or 1 or more new lesions. To qualify as an event, the toxicity must be from an intolerable AE (defined as any study drug-related AE that meets protocol guidance for treatment discontinuation, with the exception of alopecia); or death (due to any cause).

Time frame: Baseline to Progressive Disease, Unacceptable Toxicity or Death from Any Cause Up to 39 Months

Population: All randomized participants, even if a participant did not take the assigned treatment, did not receive the correct treatment, or otherwise did not follow the protocol. Censored participants: Selpercatinib - 166; Cabozantinib or Vandetanib - 61