BioCryst Begins Enrollment in Pivotal APeX-P Trial Evaluating ORLADEYO® (berotralstat) in
Pediatric Patients with Hereditary Angioedema

January 26, 2023

RESEARCH TRIANGLE PARK, N.C., Jan. 26, 2023 (GLOBE NEWSWIRE) -- BioCryst Pharmaceuticals, Inc. (Nasdaq: BCRX) today announced the
enrollment of the first patient in the pivotal APeX-P trial evaluating oral, once-daily ORLADEYO® (berotralstat) in pediatric hereditary angioedema
(HAE) patients who are 2 to <12 years of age.

“Today’s announcement marks a very important step in our continuing efforts to reduce the burden of therapy for people living with HAE around the
world with oral, once-daily ORLADEYO. Pediatric patients are a particularly important group where the challenges posed by disease and treatment
can be significant to these children and their families, especially given the uncertainty they face as they are newly diagnosed during childhood. It is
imperative that we strive to help normalize patients’ lives, as early experiences can have a lasting impact on how HAE is perceived – and managed –
for their entire lifetimes. We are excited by the opportunity to introduce this new pediatric formulation of ORLADEYO that could significantly reduce the
treatment burden for children and families impacted by HAE,” said Dr. Ryan Arnold, chief medical officer of BioCryst.

ORLADEYO is the first and only oral therapy designed specifically to prevent HAE attacks in adult and pediatric patients 12 years and older. First
approved by the U.S. Food and Drug Administration (FDA) in December 2020, ORLADEYO is available in many global markets.

APeX-P is an open-label trial designed to evaluate the pharmacokinetics (PK) and safety of ORLADEYO in pediatric HAE patients (2 to <12 years of
age). The trial will consist of an initial 12-week standard-of-care (SOC) treatment period, followed by a subsequent open-label ORLADEYO treatment
period lasting 48 weeks, with continuation up to 144 weeks. Patients will be enrolled into four dose cohorts, with body weight being used to determine
assignment to each cohort. Higher weight cohorts (Cohorts 1 and 2) will enroll first and in parallel, and safety assessments and PK modelling from all
available PK data will then be used to confirm the weight bands for sequentially enrolling Cohorts 3 and 4. The effectiveness of ORLADEYO in
APeX-P will be summarized using descriptive statistical methods. The primary endpoint of APeX-P is the characterization of the PK profile of
ORLADEYO in patients aged 2 to <12 years.

Following the completion of APeX-P, BioCryst plans to submit a supplemental New Drug Application (sNDA) for the potential expanded use of
ORLADEYO for prophylaxis to prevent attacks in pediatric HAE patients.

For more information about the APeX-P trial, visit ClinicalTrials.gov and search NCT number NCT05453968.

About ORLADEYO® (berotralstat)
ORLADEYO® (berotralstat) is the first and only oral therapy designed specifically to prevent attacks of hereditary angioedema (HAE) in adult and
pediatric patients 12 years and older. One capsule of ORLADEYO per day works to prevent HAE attacks by decreasing the activity of plasma
kallikrein.

U.S. Indication and Important Safety Information

INDICATION
ORLADEYO® (berotralstat) is a plasma kallikrein inhibitor indicated for prophylaxis to prevent attacks of hereditary angioedema (HAE) in adults and
pediatric patients 12 years and older.

Limitations of use
The safety and effectiveness of ORLADEYO for the treatment of acute HAE attacks have not been established. ORLADEYO should not be used for
the treatment of acute HAE attacks. Additional doses or dosages of ORLADEYO higher than 150 mg once daily are not recommended due to the
potential for QT prolongation.

IMPORTANT SAFETY INFORMATION

An increase in QT prolongation was observed at dosages higher than the recommended 150 mg once-daily dosage and was concentration
dependent.

The most common adverse reactions (≥10% and higher than placebo) in patients receiving ORLADEYO were abdominal pain, vomiting, diarrhea,
back pain, and gastroesophageal reflux disease.

A reduced dosage of 110 mg taken orally once daily with food is recommended in patients with moderate or severe hepatic impairment (Child-Pugh B
or C) and in patients taking chronically administered P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) inhibitors (eg, cyclosporine).

Berotralstat is a substrate of P-gp and BCRP. P-gp inducers (eg, rifampin, St. John’s wort) may decrease berotralstat plasma concentration, leading to
reduced efficacy of ORLADEYO. The use of P-gp inducers is not recommended with ORLADEYO.

ORLADEYO at a dose of 150 mg is a moderate inhibitor of CYP2D6 and CYP3A4. For concomitant medications with a narrow therapeutic index that
are predominantly metabolized by CYP2D6 or CYP3A4, appropriate monitoring and dose titration is recommended. ORLADEYO at a dose of 300 mg
is a P-gp inhibitor. Appropriate monitoring and dose titration is recommended for P-gp substrates (eg, digoxin) when coadministering with
ORLADEYO.

The safety and effectiveness of ORLADEYO in pediatric patients <12 years of age have not been established.

There are insufficient data available to inform drug-related risks with ORLADEYO use in pregnancy. There are no data on the presence of berotralstat
in human milk, its effects on the breastfed infant, or its effects on milk production.

To report SUSPECTED ADVERSE REACTIONS, contact BioCryst Pharmaceuticals, Inc. at 1-833-633-2279 or FDA at 1-800-FDA-1088
or www.fda.gov/medwatch.

Please see full Prescribing Information.

About BioCryst Pharmaceuticals
BioCryst Pharmaceuticals discovers novel, oral, small-molecule medicines that treat rare diseases in which significant unmet medical needs exist and
an enzyme plays a key role in the biological pathway of the disease. Oral, once-daily ORLADEYO® (berotralstat) is approved in the United States and
many global markets. BioCryst has active programs to develop oral medicines for multiple targets across the complement system, including
BCX10013, an oral Factor D inhibitor in clinical development. RAPIVAB® (peramivir injection) is approved in the U.S. and multiple global markets, with
post-marketing commitments ongoing. For more information, please visit the company’s website at www.biocryst.com.

Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding BioCryst’s plans and expectations for ORLADEYO. These
statements involve known and unknown risks, uncertainties and other factors which may cause actual results, performance or achievements to be
materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These statements
reflect our current views with respect to future events and are based on assumptions and are subject to risks and uncertainties. Given these
uncertainties, you should not place undue reliance on these forward-looking statements. Some of the factors that could affect the forward-looking
statements contained herein include: the ongoing COVID-19 pandemic, which could create challenges in all aspects of BioCryst’s business, including
without limitation delays, stoppages, difficulties and increased expenses with respect to BioCryst’s and its partners’ development, regulatory
processes and supply chains, negatively impact BioCryst’s ability to access the capital or credit markets to finance its operations, or have the effect of
heightening many of the risks described below or in the documents BioCryst files periodically with the Securities and Exchange Commission;
BioCryst’s ability to successfully implement its commercialization plans for, and to commercialize, ORLADEYO, which could take longer or be more
expensive than planned; the commercial viability of ORLADEYO, including its ability to achieve market acceptance; BioCryst’s ability to successfully
expand the approved indications for ORLADEYO; ongoing and future preclinical and clinical development of products and product candidates may not
have positive results; BioCryst may not be able to enroll the required number of subjects in planned clinical trials; BioCryst may not advance human
clinical trials as expected; the FDA or other applicable regulatory agency may require additional studies beyond the studies planned for products and
product candidates, may not provide regulatory clearances which may result in delay of planned clinical trials, may impose certain restrictions,
warnings, or other requirements on products and product candidates, may impose a clinical hold with respect to product candidates, or may withhold,
delay, or withdraw market approval for products and product candidates; BioCryst’s ability to successfully manage its growth and compete effectively;
risks related to the international expansion of BioCryst’s business; and actual financial results may not be consistent with expectations, including that
revenue, operating expenses and cash usage may not be within management's expected ranges. Please refer to the documents BioCryst files
periodically with the Securities and Exchange Commission, specifically BioCryst’s most recent Annual Report on Form 10-K, Quarterly Reports on
Form 10-Q, and Current Reports on Form 8-K, which identify important factors that could cause the actual results to differ materially from those
contained in BioCryst’s forward-looking statements.

BCRXW

Investor Contact:
John Bluth
+1 919 859 7910
jbluth@biocryst.com

Media Contact:
Catherine Collier Kyroulis
+1 917 886 5586
ckyroulis@biocryst.com