PBYI Puma Biotechnology Inc

On October 19, 2016, Puma Biotechnology, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc. and J.P. Morgan Securities LLC, as representatives of the underwriters named therein (the “Underwriters”), in connection with the public offering, issuance and sale by the Company of 3,750,000 shares of the Company’s common stock, par value $0.0001 per share, at the public offering price of $40.00 per share, less underwriting discounts and commissions, pursuant to an effective registration statement on Form S-3 (File No. 333-201603) and a related prospectus supplement filed with the Securities and Exchange Commission. Under the terms of the Underwriting Agreement, the Company also granted the Underwriters an option exercisable for 30 days to purchase up to an additional 562,500 shares of its common stock at the public offering price, less underwriting discounts and commissions. On October 20, 2016, the Underwriters exercised their option to purchase additional shares in full.

The Company expects to receive net proceeds from the offering of approximately $161.8 million, after deducting underwriting discounts and commissions and estimated offering expenses. The Company intends to use the net proceeds of the offering for the overall development of its drug candidates, including, but not limited to, research and development and clinical trial expenditures, pre-commercialization activities and general corporate and working capital purposes.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended, other obligations of the parties and termination provisions. The offering is expected to close on or about October 25, 2016.

The above description of the Underwriting Agreement is qualified in its entirety by reference to the full text of the Underwriting Agreement, a copy of which is filed as Exhibit 1.1 hereto and is incorporated herein by reference. Latham & Watkins LLP, counsel to the Company, has issued an opinion to the Company, dated October 21, 2016, regarding the validity of the shares of common stock to be issued and sold in the offering. A copy of the opinion is filed as Exhibit 5.1 to this Current Report on Form 8-K.