Puma Biotechnology and Knight Therapeutics Enter into Exclusive License Agreement to Commercialize NERLYNX® (neratinib) in Canada

LOS ANGELES–(BUSINESS WIRE)–Puma Biotechnology, Inc. (Nasdaq: PBYI), a biopharmaceutical company,
announced that it has entered into an exclusive License Agreement with
Knight Therapeutics Inc. (TSX: GUD) that grants Knight the exclusive
right to commercialize NERLYNX® (neratinib) in Canada.

Puma Biotechnology filed a new drug submission for NERLYNX® with Health
Canada in July 2018 for the extended adjuvant treatment of adult
patients with early stage HER2-overexpressed/amplified breast cancer
following adjuvant trastuzumab-based therapy. Under the terms of the
License Agreement, Knight will be responsible for all commercial
activities and future regulatory submissions for NERLYNX® in Canada.
Puma will receive upfront and milestone payments up to $7.2 million USD
throughout the term of this agreement, as well as double digit royalties
on net sales of NERLYNX in Canada.

“Our new agreement with Knight demonstrates our commitment to bringing
NERLYNX to patients around the world while continuing to focus our
commercial resources on the U.S. market,” stated Alan H. Auerbach, Chief
Executive Officer and President of Puma. “We are confident this new
partnership will help patients in Canada access NERLYNX at the earliest
opportunity.”

“We are excited to partner with Puma to offer a new treatment option to
Canadian breast cancer patients,” said Jonathan Ross Goodman, Chief
Executive Officer of Knight. “While adjuvant trastuzumab-based therapy
has been shown to reduce the risk of recurrence in early stage
HER2-positive breast cancer, up to 25% of patients treated with adjuvant
trastuzumab will have a recurrence. NERLYNX® has been shown to
significantly reduce the risk of recurrence in those patients who were
previously treated with trastuzumab.”

Neratinib was approved by the U.S. Food and Drug Administration (FDA) in
July 2017 for the extended adjuvant treatment of adult patients with
early stage HER2-positive breast cancer following adjuvant
trastuzumab-based therapy, and is marketed in the United States as
NERLYNX® (neratinib) tablets.

About Puma Biotechnology

Puma Biotechnology, Inc. is a biopharmaceutical company with a focus on
the development and commercialization of innovative products to enhance
cancer care. Puma in-licenses the global development and
commercialization rights to three drug candidates — PB272 (neratinib,
oral), PB272 (neratinib, intravenous) and PB357. Neratinib, oral was
approved by the U.S. Food and Drug Administration in July 2017 for the
extended adjuvant treatment of adult patients with early stage
HER2-overexpressed/amplified breast cancer, following adjuvant
trastuzumab-based therapy, and is marketed in the United States as
NERLYNX® (neratinib) tablets. NERLYNX was granted marketing
authorization by the European Commission for the extended adjuvant
treatment of hormone receptor-positive HER2-positive early stage breast
cancer in September 2018. NERLYNX is a registered trademark of Puma
Biotechnology, Inc.

Further information about Puma Biotechnology may be found at www.pumabiotechnology.com.

Important Safety Information Regarding NERLYNX® (neratinib)
U.S. Indication

NERLYNX® (neratinib) tablets, for oral use

INDICATIONS AND USAGE: NERLYNX is a kinase inhibitor indicated
for the extended adjuvant treatment of adult patients with HER2
overexpressed/amplified breast cancer, to follow adjuvant
trastuzumab-based therapy.

CONTRAINDICATIONS: None

WARNINGS AND PRECAUTIONS:

Diarrhea: Aggressively manage diarrhea occurring despite
recommended prophylaxis with additional antidiarrheals, fluids, and
electrolytes as clinically indicated. Withhold NERLYNX in patients
experiencing severe and/or persistent diarrhea. Permanently discontinue
NERLYNX in patients experiencing Grade 4 diarrhea or Grade≥ 2 diarrhea
that occurs after maximal dose reduction.

• Hepatotoxicity: Monitor liver function tests monthly for the
first 3 months of treatment, then every 3 months while on treatment and
as clinically indicated. Withhold NERLYNX in patients experiencing Grade
3 liver abnormalities and permanently discontinue NERLYNX inpatients
experiencing Grade 4 liver abnormalities.

• Embryo-Fetal Toxicity: NERLYNX can cause fetal harm. Advise
patients of potential risk to a fetus and to use effective contraception.

ADVERSE REACTIONS: The most common adverse reactions (≥ 5%) were
diarrhea, nausea, abdominal pain, fatigue, vomiting, rash, stomatitis,
decreased appetite, muscle spasms, dyspepsia, AST or ALT increase, nail
disorder, dry skin, abdominal distention, epistaxis, weight decreased
and urinary tract infection.

To report SUSPECTED ADVERSE REACTIONS, contact Puma Biotechnology,
Inc. at 1-844-NERLYNX (1-844-637-5969) and
www.NERLYNX.com
or FDA at 1-800-FDA-1088 or
www.fda.gov/medwatch.

DRUG INTERACTIONS:

  • Gastric acid reducing agents: Avoid concomitant use with proton pump
    inhibitors (PPI) and H2-receptor antagonists. Separate NERLYNX by 3
    hours after antacid dosing.
  • Strong or moderate CYP3A4 inhibitors: Avoid concomitant use.
  • Strong or moderate CYP3A4 inducers: Avoid concomitant use.
  • P-glycoprotein (P-gp) substrates: Monitor for adverse reactions of
    narrow therapeutic agents that are P-gp substrates when used
    concomitantly with NERLYNX.

USE IN SPECIFIC POPULATIONS:

•Lactation: Advise women not to breastfeed.

Please see Full
Prescribing Information
for additional safety information.

To help ensure patients have access to NERLYNX, Puma has implemented the
Puma Patient Lynx support program to assist patients and health care
providers with reimbursement support and referrals to resources that can
help with financial assistance. More information on the Puma Patient
Lynx program can be found at www.NERLYNX.com
or 1-855-816-5421.

The recommended dose of NERLYNX is 240 mg (six 40 mg tablets) given
orally once daily with food, continuously for one year. Antidiarrheal
prophylaxis should be initiated with the first dose of NERLYNX and
continued during the first 2 months (56 days) of treatment and as needed
thereafter.

Further information about Puma Biotechnology can be found at www.pumabiotechnology.com.

Forward-Looking Statements

This press release contains forward-looking statements, including
statements regarding timeframes for regulatory approval and
commercialization of NERLYNX in Canada. All forward-looking statements
involve risks and uncertainties that could cause Puma’s actual results
to differ materially from the anticipated results and expectations
expressed in these forward-looking statements. These statements are
based on current expectations, forecasts and assumptions, and actual
outcomes and results could differ materially from these statements due
to a number of factors, which include, but are not limited to, the risk
factors disclosed in the periodic and current reports filed by Puma with
the Securities and Exchange Commission from time to time, including
Puma’s Annual Report on Form 10-K for the year ended December 31, 2017.
Readers are cautioned not to place undue reliance on these
forward-looking statements, which speak only as of the date hereof. Puma
assumes no obligation to update these forward-looking statements, except
as required by law.

Contacts

Alan H. Auerbach or Mariann Ohanesian, Puma Biotechnology, Inc., +1 424
248 6500
info@pumabiotechnology.com
ir@pumabiotechnology.com

David Schull or Alex Fudukidis, Russo Partners, +1-212-845-4271
david.schull@russopartnersllc.com
alex.fudukidis@russopartnersllc.com