New Study Shows More Than Half of Teens with Peanut Allergy Visited the E.R., More Than One-Third Required Hospitalization Due to Accidental Exposure to Peanut

— 4 in 10 Teens believe they have a great or very great chance or
certainty of dying from accidental exposure —

NEW ORLEANS–(BUSINESS WIRE)–Aimmune Therapeutics, Inc. (Nasdaq: AIMT), a biopharmaceutical company
developing treatments for life-threatening food allergies, today
announced results of a new study of U.S. adolescents with peanut allergy
that found more than half required a visit to the emergency room or
urgent care and one-third required hospitalization as a result of peanut
exposure in the past 12 months, despite the fact that 100% of those
surveyed reported actively avoiding peanut products. The study findings
were presented here today in a poster session at the International
Society for Pharmacoeconomics Outcomes Research (ISPOR) 2019 Annual
Meeting in New Orleans.

“These results illustrate how peanut avoidance, in practical day-to-day
terms, provides neither the protection nor the confidence that patients
are able to appropriately manage their disease in the real world,” said
William McCann, M.D., senior author and Director, Vice President and
Chief Medical Officer of Allergy Partners, the large single-specialty
allergy practice in the U.S., focusing on treating asthma and allergic
disease with locations across 20 states. “In addition to the urgent
medical interventions that are required, these findings elucidate the
anxiety felt by these adolescents who live in daily fear of accidental
exposure, respiratory distress and even death. Clearly, the strategy of
avoidance is not working given the amount of medical interventions these
teens require. New options are needed for these patients to help
alleviate the constant fear and serious consequences of accidental
exposures.”

Study Design

The study, titled “Real-World Experience of Peanut-Allergic Adolescents
in the United States: Health-Related Concerns and Resource Utilization
for Peanut Allergy” (abstract #PRS60), was conducted to better
understand the experience of peanut allergic adolescents and their use
of healthcare resources to manage peanut allergy and health-related
concerns. The study recruited 102 adolescents ages 13 to 17 (mean age:
14.7 years) with self-reported, physician-diagnosed peanut allergy using
commercial research panels. Study participants took an online survey,
which included the Food Allergy Independent Measure (FAIM) to assess
perceived risk and expectations of allergy outcomes.

Study Results
Key findings were as follows:

Use of Healthcare Resources for Peanut Allergy in Past Year

• 57% of respondents required at least one visit to an emergency room or
  urgent care facility and 37% required at least one hospitalization
  stay of overnight or longer as a result of peanut exposure, despite
  100% of survey participants saying they actively avoided peanut
  products.
• 55% reported at least one unscheduled visit to an allergist due to a
  reaction.
• 60% reported at least one use of an epinephrine autoinjector and 27%
  reported needing an epinephrine autoinjector without having access to
  one.

Health-Related Concerns of Peanut Allergy

• 35% of respondents said they felt “not at all confident,” “not very
  confident” or “somewhat confident” managing peanut allergy reactions.
• 44% of respondents said they felt “not at all in control,” “not very
  much in control” or “somewhat in control” of their peanut allergy
  despite the fact that 93% had been prescribed an epinephrine
  autoinjector (with 88% carrying it 75% or more of the time), and 100%
  said they actively avoided peanut products.
• 46% reported physical symptoms experienced during a reaction as the
  most concerning aspect of peanut allergy, with respiratory symptoms
  considered the most worrisome (reported by 75%). Other concerning
  aspects were having quick access to needed care (25%), impact on
  social interactions (10%), impact on mental health (10%), and impact
  on family (9%).
• 40% of respondents said there was a “great chance,” “very great
  chance” or a “certainty” of death resulting from accidentally eating
  something to which they were allergic.

The abstract of the ISPOR 2019 presentation can be found at www.ispor.org,
and the poster presentation can be found in the News & Events section of
Aimmune Therapeutics’ website at www.aimmune.com.

About Peanut Allergy

Peanut allergy, a common type of food allergy, has become increasingly
prevalent in recent years, particularly among children (Sicherer 2010).
Recent claims-based data suggest that approximately 2.2% of all children
and adolescents in the United States (1.25 million) have peanut allergy
(Lieberman 2018). Individuals with peanut allergy who are exposed to
peanuts can develop various allergic symptoms that range in severity and
onset. The most severe systemic allergic reaction is anaphylaxis, which
may be life-threatening and requires immediate treatment with
epinephrine (Boyce 2010). Currently, no curative treatments exist for
peanut allergy, and recommended management strategies include avoiding
peanuts and appropriately treating symptoms of a reaction (Boyce 2010;
Sitton 2018). Given the potential severity of symptoms and need for
close management, living with food allergies such as peanut allergy
present day-to-day concerns and challenges for allergic individuals and
their families (Cummings 2010), and contribute to increased healthcare
resource utilization and economic burden (Gupta 2013).

About Aimmune Therapeutics

Aimmune Therapeutics, Inc., is a biopharmaceutical company developing
oral treatments for life-threatening food allergies. The company’s Characterized
Oral Desensitization
ImmunoTherapy
(CODIT™) approach is intended to provide meaningful levels of protection
against allergic reactions resulting from exposure to food allergens by
desensitizing patients with defined, precise amounts of key allergens.
Aimmune’s first investigational biologic product, AR101, is being
developed as a treatment to reduce the frequency and severity of adverse
events following exposure to peanut. The BLA for AR101 is under review
by the U.S. FDA, which in 2015 granted AR101 Breakthrough Therapy
Designation for the desensitization of peanut-allergic patients 4 to 17
years of age. Aimmune expects to file for marketing approval of AR101 in
Europe in mid-2019. Aimmune has filed an IND application for its second
product, AR201 for the treatment of egg allergy, and intends to start a
randomized phase 2 clinical trial in mid-2019. For more information,
please see www.aimmune.com.

Forward-Looking Statements

Statements contained in this press release regarding matters that are
not historical facts are “forward-looking statements” within the meaning
of the Private Securities Litigation Reform Act of 1995. Because such
statements are subject to risks and uncertainties, actual results may
differ materially from those expressed or implied by such
forward-looking statements. Such statements include, but are not limited
to, statements regarding: Aimmune’s expectations regarding the potential
benefits of AR101; Aimmune’s expectations regarding the review of the
BLA for AR101; Aimmune’s expectations regarding the planned timing and
filing for marketing approval of AR101 in Europe; Aimmune’s expectations
on the timing of initiating a Phase 2 clinical trial for AR201; and
Aimmune’s expectations regarding potential applications of the CODIT™
approach to treating life-threatening food allergies. Risks and
uncertainties that contribute to the uncertain nature of the
forward-looking statements include: the expectation that Aimmune will
need additional funds to finance its operations; Aimmune’s or any of its
collaborative partners’ ability to initiate and/or complete clinical
trials; the unpredictability of the regulatory process; the possibility
that Aimmune’s or any of its collaborative partners’ clinical trials
will not be successful; Aimmune’s dependence on the success of AR101;
Aimmune’s reliance on third parties for the manufacture of Aimmune’s
product candidates; possible regulatory developments in the United
States and foreign countries; and Aimmune’s ability to attract and
retain senior management personnel. These and other risks and
uncertainties are described more fully in Aimmune’s most recent filings
with the Securities and Exchange Commission, including its Quarterly
Report on Form 10-Q for the quarter ended March 31, 2019. All
forward-looking statements contained in this press release speak only as
of the date on which they were made. Aimmune undertakes no obligation to
update such statements to reflect events that occur or circumstances
that exist after the date on which they were made.

This press release concerns AR101, a product candidate that is under
clinical investigation, and AR201, a product candidate that Aimmune
expects will be under clinical investigation in 2019. Neither AR101 nor
AR201 has been approved for marketing by the FDA or the European
Medicines Agency (EMA). AR101 and AR201 are currently limited to
investigational use, and no representation is made as to their safety or
effectiveness for the purposes for which they are being investigated.

Contacts

Investors:
Eric Bjerkholt
(650) 376-5582
[email protected]

Media:
Jerica
Pitts
(312) 858-3469
[email protected]