Study to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of JNJ-42756493 (Erdafitinib) in Participants With Advanced Hepatocellular Carcinoma

The purpose of this study is to determine recommended Phase 2 dose \[RP2D\]) and the objective response rate of JNJ-42756493 (erdafitinib) in advanced hepatocellular carcinoma (HCC) participants with fibroblast growth factor (FGF) 19 amplification.

This is an open-label (all people know the identity of the intervention), multicenter (when more than one hospital or medical school team work on a medical research study), 2 parts (First, dose escalation Phase and second, dose expansion Phase) study to evaluate the safety, pharmacokinetics, pharmacodynamics, and clinical responses of JNJ-42756493 (erdafitinib) in Asian participants with advanced HCC. The duration of study will be approximately 11 months per participant. The study consists of 2 periods: Screening (28 days before study commences on Day 1); Open-label Treatment (dose escalation portion of the trial \[Part 1\]), participants are enrolled into cohorts at increasing dose levels of JNJ-42756493 (erdafitinib) in 28 day treatment cycles. Part 2, the cohort expansion part of the trial, will further explore the recommended phase 2 dose (RP2D) of JNJ-42756493 (erdafitinib) as determined in Part 1; and follow-up Phase (up to 6 months). Blood samples will be collected for evaluation of safety, pharmacokinetics, pharmacodynamics, and predictive biomarkers at pre-dose and post-dose of study treatment. Recommended Phase 2 dose (RP2D) for JNJ-42756493 (erdafitinib) will be evaluated primarily. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* Histologically or cytologically confirmed hepatocellular carcinoma (HCC). (histology or cytology from prior tumor biopsy specimen is acceptable). For Part 1 continuous dosing regimen and Part 2, HCC participants must have fibroblast growth factor (FGF) 19 amplification based on central laboratory results
* Participant must have advanced disease and meet all the following criteria: Disease progression after previous surgical or local-regional therapy, if any; Disease ineligible for surgical or local-regional therapy or systemic therapy; Received no more than 1 line of systemic therapy (Participants who are intolerant to previous systemic therapy are allowed.)
* Cirrhotic status of Child-Pugh class A: Participants with Child-Pugh class B score of 7 may be considered in Part 2 if no pharmacokinetic (PK) and safety issues are identified in Part 1 from subjects with Child-Pugh class A
* Eastern Cooperative Oncology Group (ECOG) performance status score 0 or 1
* Participants with adequate bone marrow, liver, renal function, and electrolytes according to protocol-defined criteria within the 14 days before the first dose of study drug
* Negative pregnancy test (urine or serum beta human chorionic gonadotropin \[beta (b)-hCG\]) at Screening for women of child bearing potential who are sexually active

Exclusion Criteria:

* Received systemic chemotherapy, targeted therapies, definitive radiotherapy, or treatment with an investigational anticancer agent within 2 weeks (in the case of nitrosoureas and mitomycin C, within 6 weeks; in the case of immunotherapy, within 4 weeks) before the first administration of study drug
* Prior liver transplant
* Known fibrolamellar HCC or mixed cholangiocarcinoma and HCC
* Clinically active serious infections greater than (\>) Common Terminology Criteria for adverse events (AEs) grade 2
* Participants with persistent calcium or phosphate \> upper limits of normal (ULN) during screening (within 14 days prior to Day 1 of Cycle 1 up until pre-dose of Cycle 1) and despite medical management of calcium or phosphate levels