A Study of Selpercatinib After Surgery or Radiation in Participants With Non-Small Cell Lung Cancer (NSCLC)

Inclusion Criteria:

• Must have histologically confirmed Stage IB, II, or IIIA NSCLC.

• Must have an activating RET gene fusion in tumor based on polymerase chain reaction (PCR), next generation sequencing (NGS), or another molecular test per sponsor'sapproval.

• Must have received definitive locoregional therapy with curative intent (surgery orradiotherapy) for Stage IB, II, or IIIA NSCLC.

-- Must have undergone the available anti-cancer therapy (including chemotherapy ordurvalumab) or not be suitable for it, based on the investigator's discretion.

• Maximum time allowed between definitive therapy completion and randomization mustbe:

• 10 weeks if no chemotherapy was administered

• 26 weeks if adjuvant chemotherapy was administered

• Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.

• Adequate hematologic, hepatic, and renal function.

• Willingness of men and women of reproductive potential to observe conventional andhighly effective birth control for the duration of the study and for at least 2weeks after last dose of study drug.

Exclusion Criteria:

• Additional oncogenic drivers in NSCLC, if known.

• Evidence of small cell lung cancer.

• Clinical or radiologic evidence of disease recurrence or progression followingdefinitive therapy.

• Known or suspected interstitial fibrosis or interstitial lung disease or history of (noninfectious) pneumonitis that required steroids.

• Clinically significant active cardiovascular disease or history of myocardialinfarction within six months prior to planned start of selpercatinib or prolongationof the QT interval corrected for heart rate using Fridericia's formula (QTcF)greater than 470 milliseconds.

• Have known uncontrolled human immunodeficiency virus (HIV)-1/2 infection.

• Have known active hepatitis B or C.

• Active uncontrolled systemic bacterial, viral, or fungal infection or seriousongoing intercurrent illness, such as hypertension or diabetes, despite optimaltreatment.

• Major surgery within 4 weeks prior to planned start of selpercatinib.

• Clinically significant active malabsorption syndrome or other condition likely toaffect gastrointestinal absorption of the study drug.

• Other malignancy unless nonmelanoma skin cancer, carcinoma in situ of the cervix orother in situ cancers or a malignancy diagnosed greater than or equal to two yearspreviously and not currently active.

• Pregnancy or lactation.

• Prior treatment with a selective RET inhibitor (e.g. selpercatinib or pralsetinib).