U.S. Food and Drug Administration Approves Puma’s NERLYNX™ (neratinib) for Extended Adjuvant Treatment of HER2-Positive Early Stage Breast Cancer

  • Neratinib becomes the first anti-HER2 treatment to be FDA-approved
    as extended adjuvant therapy for early-stage HER2-positive breast
    cancer following adjuvant trastuzumab-based therapy.
  • Treatment with neratinib resulted in a 34% reduction in the risk of
    invasive disease recurrence or death versus placebo after patients
    completed one year of therapy following a trastuzumab-based regimen.
  • Neratinib addresses an unmet medical need, as up to 25% of
    HER2-positive early-stage breast cancer patients treated with
    trastuzumab-based adjuvant treatment experience a recurrence.

LOS ANGELES–(BUSINESS WIRE)–Puma Biotechnology, Inc. (Nasdaq: PBYI) today announced that the U.S.
Food and Drug Administration (FDA) has approved NERLYNX™ (neratinib),
formerly known as PB272, a once-daily oral tyrosine kinase inhibitor for
the extended adjuvant treatment of adult patients with early stage
HER2-overexpressed/amplified breast cancer, following adjuvant
trastuzumab-based therapy. Puma expects neratinib to become commercially
available in September 2017 and to be marketed as NERLYNX.

FDA approval was based on the Phase III ExteNET trial, a multicenter,
randomized, double-blind, placebo-controlled trial of neratinib
following adjuvant trastuzumab treatment. Women (n=2,840) with
early-stage HER2-positive breast cancer and within two years of
completing adjuvant trastuzumab were randomized to receive either
neratinib (n=1420) or placebo (n=1420) for one year.

The results of the ExteNET trial demonstrated that after two years of
follow-up, invasive disease-free survival (iDFS) was 94.2% in patients
treated with neratinib compared with 91.9% in those receiving placebo
(HR 0.66; 95% CI: 0.49, 0.90, p=0.008).

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, weight loss, and urinary tract infection. The most
common adverse reaction leading to discontinuation was diarrhea, which
was observed in 16.8% of neratinib-treated patients. Hepatotoxicity or
increases in liver transaminases led to drug discontinuation in 1.7% of
neratinib-treated patients.

“The fear of recurrence is ever present in the minds of most women with
breast cancer, from the moment they are diagnosed to long after they
finish adjuvant treatment,” said Marisa C. Weiss, M.D., Chief Medical
Officer and Founder of Breastcancer.org. “New and effective innovative
therapeutic options provide huge hope to patients and their families,
giving them a better chance of overcoming breast cancer with a chance
for a full life.”

“Despite advances in the treatment of early stage HER2-positive breast
cancer, there remains a need for further therapeutic improvements in
order to attempt to further reduce the risk of disease recurrence,” said
Puma Biotechnology CEO and President Alan H. Auerbach. “We are pleased
to be able to bring this new medicine to patients with breast cancer. We
would like to express our appreciation to the patients, caregivers and
physicians who contributed to the neratinib clinical development program
and, more specifically, the ExteNET trial.”

The full prescribing information for NERLYNX will be made available at WWW.NERLYNX.COM.
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 NERLYNX dose and
continued during the first 2 cycles (56 days) of treatment and as needed
thereafter. A Marketing Authorisation Application for neratinib is under
review by the European Medicines Agency (EMA).

About HER2-Positive Breast Cancer

Approximately 20 to 25 percent of breast cancer tumors over-express the
HER2 protein. HER2-positive breast cancer is often more aggressive than
other types of breast cancer, increasing the risk of disease progression
and death. Although research has shown that trastuzumab can reduce the
risk of early stage HER2-positive breast cancer returning after surgery,
up to 25% of patients treated with trastuzumab experience recurrence.

Indication

NERLYNX™ is a tyrosine kinase inhibitor indicated for the extended
adjuvant treatment of adult patients with early stage
HER2-overexpressed/amplified breast cancer, to follow adjuvant
trastuzumab-based therapy.

Patient Support

Puma has developed the Puma Patient Lynx support program to provide
patients and healthcare providers with assistance related to questions
on accessing neratinib and referrals to resources that can help with reimbursement
and financial assistance. More information on the Puma Patient Lynx
program can be found at www.NERLYNX.com
or (1-855-816-5421).

Important Safety Information

There are possible side effects of NERLYNX. Patients must contact their
doctor right away if they experience any of these symptoms. NERLYNX
treatment may be stopped or the dose may be lowered if the patient
experiences any of these side effects.

Diarrhea

Diarrhea is a common side effect of NERLYNX. The diarrhea
may be severe, and you may get dehydrated. Your healthcare provider
should prescribe the medicine loperamide for you during your first 2
cycles (56 days) of NERLYNX and then as needed. To help prevent or
reduce diarrhea:

  • You should start taking loperamide with your first dose of NERLYNX.
  • Keep taking loperamide during the first 2 cycles (56 days) of NERLYNX
    treatment and then as needed. Your healthcare provider will tell you
    exactly how much and how often to take loperamide.
  • While taking loperamide, you and your healthcare provider should try
    to keep the number of bowel movements that you have at 1 or 2 bowel
    movements each day.
  • Tell your healthcare provider if you have more than 2 bowel movements
    in 1 day, or you have diarrhea that does not go away.

Contact your healthcare provider right away if you have severe
diarrhea or if you have diarrhea along with weakness, dizziness, or
fever.

Liver Problems

Changes in liver function tests are common with NERLYNX. The patient’s
doctor will do tests before starting treatment, monthly during the first
3 months, and then every 3 months as needed during treatment with
NERLYNX. NERLYNX treatment may be stopped or the dose may be lowered if
your liver tests show severe problems. Symptoms of liver problems may
include tiredness, nausea, vomiting, pain in the right upper
stomach-area (abdomen), fever, rash, itching, yellowing of your skin or
whites of your eyes.

Pregnancy

Patients should tell their doctor if they are planning to become
pregnant, are pregnant, plan to breastfeed, or are breastfeeding.
NERLYNX can harm your unborn baby. Birth control should be used while a
patient is receiving NERLYNX and for at least 1 month after the last
dose. If patients are exposed to NERLYNX during pregnancy, they must
contact their healthcare provider right away.

Common side effects in patients treated with NERLYNX

In clinical studies, the most common side effects seen in patients
taking NERLYNX were diarrhea, nausea, abdominal pain, fatigue, vomiting,
rash, stomatitis (dry or inflamed mouth, or mouth sores), decreased
appetite, muscle spasms, dyspepsia, changes in liver blood tests
results, nail problems, dry skin, abdominal distention, weight loss, and
urinary tract infection.

Patients should tell their doctor right away if they are experiencing
any side effects. Report side effects to the FDA at 1-800-FDA-1088 or
 http://www.FDA.gov/medwatch.
Patients and caregivers may also report side effects to Puma
Biotechnology at 1-844-NERLYNX (1-844-637-5969).

Please see Full Prescribing Information, available at www.NERLYNX.com.

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. The Company in-licenses the global development and
commercialization rights to three drug candidates—PB272 (neratinib
(oral)), PB272 (neratinib (intravenous)) and PB357. Neratinib is a
potent irreversible tyrosine kinase inhibitor that blocks signal
transduction through the epidermal growth factor receptors, HER1, HER2
and HER4. Currently, the Company is primarily focused on the development
of the oral version of neratinib, and its most advanced drug candidates
are directed at the treatment of HER2-positive breast cancer. The
Company believes that neratinib has clinical application in the
treatment of several other cancers as well, including non-small cell
lung cancer and other tumor types that over-express or have a mutation
in HER2. 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 the Company’s expectation that neratinib will
become commercially available in September 2017. All forward-looking
statements included in this press release involve risks and
uncertainties that could cause the Company’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 fact that the
Company has no product revenue and no products approved for marketing,
the Company’s dependence on PB272, which is still under development and
may never receive regulatory approval, the challenges associated with
conducting and enrolling clinical trials, the risk that the results of
clinical trials may not support the Company’s drug candidate claims,
even if approved, the risk that physicians and patients may not accept
or use the Company’s products, the Company’s reliance on third parties
to conduct its clinical trials and to formulate and manufacture its drug
candidates, risks pertaining to securities class action, derivative and
defamation lawsuits, the Company’s dependence on licensed intellectual
property, and the other risk factors disclosed in the periodic and
current reports filed by the Company with the Securities and Exchange
Commission from time to time, including the Company’s Annual Report on
Form 10-K for the year ended December 31, 2016. Readers are cautioned
not to place undue reliance on these forward-looking statements, which
speak only as of the date hereof. The Company assumes no obligation to
update these forward-looking statements, except as required by law.

Contacts

Puma Biotechnology, Inc.
Alan H. Auerbach or Mariann Ohanesian, +1
424 248 6500
info@pumabiotechnology.com
ir@pumabiotechnology.com
or
Russo
Partners
David Schull or Amiad Finkelthal, +1-212-845-4200
david.schull@russopartnersllc.com
amiad.finkelthal@russopartnersllc.com