Phase 1b Trial of Lenvatinib Plus Pembrolizumab in Participants With Selected Solid Tumors

Inclusion Criteria:

* Histologically and/or cytologically confirmed selected solid tumor types that have progressed after treatment with standard therapies or for which there are no other appropriate therapies available.

The selected tumor types are: non-small cell lung cancer, predominantly clear cell renal cell carcinoma, endometrial carcinoma, urothelial carcinoma, squamous cell carcinoma of the head and neck, or melanoma (excluding uveal melanoma)

* At least 1 measurable target lesion according to modified Response Evaluation Criteria In Solid Tumors (RECIST) 1.1
* Participants must have an Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS) of 0 to 1.
* Adequate liver function as evidenced by bilirubin ≤1.5×ULN and alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) ≤3×ULN (in the case of liver metastases ≤5×ULN). In case ALP is \>3×ULN (in the absence of liver metastases) or \>5×ULN (in the presence of liver metastases) AND the participant also is known to have bone metastases, the liver-specific ALP must be separated from the total and used to assess the liver function instead of the total ALP.
* Males or females age ≥20 years at the time of informed consent
* Life expectancy of 12 weeks or more
* Voluntary agreement to provide written informed consent and the willingness and ability to comply with all aspects of the protocol

Exclusion Criteria:

* Prior anticancer treatment within 28 days (or 5 times the half-life time, whichever is shorter) or any investigational agent within 28 days prior to the first dose of study drugs. All toxicities related to prior treatments must be resolved to Grade ≤1 (except alopecia).
* Prior treatment with lenvatinib or any anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, excluding cancer types such as melanoma and non-small cell lung cancer where prior treatment with one anti-PD-1, anti-PD-L1, or anti-PD-L2 agent is allowed
* Participants must have recovered adequately from any complications from major surgery prior to starting therapy.
* New York Heart Association congestive heart failure of grade II or above, unstable angina, myocardial infarction within the past 6 months, or serious cardiac arrhythmia associated with significant cardiovascular impairment within the past 6 months
* Prolongation of QTc (Fridericia formula) interval to \>480 milliseconds (ms)
* Active infection (any infection requiring systemic treatment)
* Participant is known to be positive for Human Immunodeficiency Virus (HIV), Hepatitis B, or Hepatitis C
* Known intolerance to either of the study drugs (or any of the excipients)
* History of organ allograft
* Any medical or other condition which, in the opinion of the investigator, would preclude participation in a clinical trial
* Has a history of (non-infectious) pneumonitis that required steroids or current pneumonitis, or has a history of interstitial lung disease
* Females who are breastfeeding or pregnant at Screening or Baseline.
* Females of childbearing potential.
* Participants must be on a stable dose of the same oral hormonal contraceptive product for at least 4 weeks before dosing with study drug and for the duration of the study.