 This is an open label, 2-period, fixed-sequence study in 15 healthy adult subjects under fed conditions. On Day 1 of Period 1 Treatment A, a single oral dose of neratinib will be administered followed by PK sampling for 72 hours. In Period 2 Treatment B, multiple oral doses of lansoprazole will be administered once daily for 7 consecutive days with a single oral dose of neratinib administered on Day 5. PK sampling for neratinib will be taken for 72 hours following neratinib dosing on Day 5. The washout period will be at least 14 days between each neratinib dose. 