X0306 4 2016-02-01 0 0001509190 ARATANA THERAPEUTICS, INC. PETX 0001201050 TOOMAN CRAIG A C/O ARATANA THERAPEUTICS, INC. 11400 TOMAHAWK CREEK PARKWAY, SUITE 340 LEAWOOD KS 66211 0 1 0 0 CHIEF FINANCIAL OFFICER COMMON STOCK 2016-02-01 4 S 0 2806 3.3628 D 102424 D The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 25, 2015, and represents shares sold to cover tax liability incident to the vesting of shares of restricted stock. This sale constitutes the final sale under such trading plan. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.33 to $3.39, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. /s/ Craig A. Tooman 2016-02-02