Arrowhead Pharmaceuticals Reports Fiscal 2018 Year End Results

Conference Call and Webcast Today at 4:30 p.m. EST

PASADENA, Calif.–(BUSINESS WIRE)–Dec. 11, 2018–
Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced financial
results for its fiscal 2018 fourth quarter and year ended September 30,
2018. The company is hosting a conference call at 4:30 p.m. EST to
discuss results.

Conference Call and Webcast Details

Investors may access a live audio webcast on the Company’s website at http://ir.arrowheadpharma.com/events.cfm.
For analysts that wish to participate in the conference call, please
dial 855-215-6159 or 315-625-6887 and provide Conference ID 6744427.

A replay of the webcast will be available on the company’s website
approximately two hours after the conclusion of the call and will remain
available for 90 days. An audio replay will also be available
approximately two hours after the conclusion of the call and will be
available for 3 days. To access the audio replay, dial 855-859-2056 or
404-537-3406 and provide Conference ID 6744427.

Selected Fiscal 2018 and Recent Events

• Hosted an Analyst R&D Day in September 2017 to highlight the following:
  • The Targeted RNAi Molecule platform, or TRiM^TM, which
    utilizes ligand-mediated delivery and is designed to enable
    tissue-specific targeting, while being structurally simple. The
    TRiM^TM platform offers several potential competitive
    advantages including:
    • A more sophisticated RNAi trigger selection and screening
      process that identifies potent sequences rapidly in locations
      that RNAi competitors may miss
    • Multiple routes of administration including subcutaneous,
      intravenous, and inhaled
    • Faster time to clinical candidates
    • Optimal pharmacologic activity and long duration-of-effect
    • Potentially wide safety margins
    • Simplified manufacturing at reduced cost
    • And, the promise of taking RNAi to tissues beyond the liver
  • Presented new clinical data at HEP DART 2017 and EASL 2018
    demonstrating up to 5.3 Log10 reduction in HBV s-antigen and a
    Sustained Host Response in 50% of hepatitis B patients following
    first generation RNAi therapy, ARC-520, in the 2001 open label
    extension study
    • One patient serocleared all viral markers, including HBsAg
  • Began a Phase 1 study of ARO-AAT, Arrowhead’s second generation
    subcutaneously administered RNAi therapeutic being developed as a
    treatment for a rare genetic liver disease associated with alpha-1
    antitrypsin deficiency
  • Began a Phase 1/2 study of ARO-HBV, a third-generation
    subcutaneously administered RNAi therapeutic candidate being
    developed as a potential treatment for patients with chronic
    hepatitis B virus infection
  • Announced that Amgen had administered the first dose of AMG 890,
    formerly ARO-LPA, in a Phase 1 clinical study, which earned
    Arrowhead a $10 million milestone payment
  • Presented clinical data on ARO-AAT at the Alpha-1 National
    Education Conference and at the AASLD Liver Meeting 2018
    demonstrating:
    • Three monthly doses of 300 mg ARO-AAT led to reductions in
      serum alpha-1 antitrypsin to below the level of quantitation
      in 100% of subjects
    • Reductions were sustained for greater than 14 weeks indicating
      that quarterly or less frequent dosing appears feasible
    • Single and multiple doses of ARO-AAT appeared to be
      well-tolerated at all doses tested
  • Presented clinical data on ARO-HBV at the World
    Gastroenterologists Summit and at the AASLD Liver Meeting 2018
    demonstrating:
    • Mean HBsAg reduction of -1.9 Log10 (-98.7%) with a range of
      -1.3 Log10 (-95.0%) to -3.8 Log10 (-99.98%)
    • ARO-HBV appeared to be well-tolerated at monthly doses up to
      400 mg
  • Signed a license agreement with Janssen Pharmaceuticals, Inc.,
    part of the Janssen Pharmaceuticals Companies of Johnson &
    Johnson, for ARO-HBV and a collaboration agreement for up to three
    RNAi therapeutic candidates that use our proprietary TRiM^TM
    platform against new targets to be selected by Janssen
    • The total potential deal value is approximately $3.7 billion
      plus royalties on commercial sales
    • Received $175 million as an upfront payment and received $75
      million in the form of an equity investment by Johnson &
      Johnson Innovation – JJDC, Inc., at a price of $23.00 per
      share of Arrowhead common stock
  • Hosted an R&D Day in October 2018 to discuss in more detail our
    emerging pipeline of RNAi therapeutics that leverage the TRiM^TM
    platform
  • Filed for regulatory clearance to begin a Phase 1 study of
    ARO-ANG3, an RNAi-based investigational medicine targeting
    angiopoietin like protein 3 (ANGPTL3) being developed for the
    treatment of dyslipidemias and metabolic diseases

Selected Fiscal 2018 Year End Financial Results

About Arrowhead Pharmaceuticals

Arrowhead Pharmaceuticals develops medicines that treat intractable
diseases by silencing the genes that cause them. Using a broad portfolio
of RNA chemistries and efficient modes of delivery, Arrowhead therapies
trigger the RNA interference mechanism to induce rapid, deep, and
durable knockdown of target genes. RNA interference, or RNAi, is a
mechanism present in living cells that inhibits the expression of a
specific gene, thereby affecting the production of a specific protein.
Arrowhead’s RNAi-based therapeutics leverage this natural pathway of
gene silencing.

For more information, please visit www.arrowheadpharma.com,
or follow us on Twitter @ArrowheadPharma.
To be added to the Company’s email list and receive news directly,
please visit http://ir.arrowheadpharma.com/email-alerts.

Safe Harbor Statement under the Private Securities Litigation Reform
Act:

This news release contains forward-looking statements within the
meaning of the “safe harbor” provisions of the Private Securities
Litigation Reform Act of 1995. These statements are based upon our
current expectations and speak only as of the date hereof. Our actual
results may differ materially and adversely from those expressed in any
forward-looking statements as a result of various factors and
uncertainties, including the safety and efficacy of our product
candidates, the duration and impact of regulatory delays in our clinical
programs, our ability to finance our operations, the likelihood and
timing of the receipt of future milestone and licensing fees, the future
success of our scientific studies, our ability to successfully develop
and commercialize drug candidates, the timing for starting and
completing clinical trials, rapid technological change in our markets,
and the enforcement of our intellectual property rights. Our most recent
Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q
discuss some of the important risk factors that may affect our business,
results of operations and financial condition. We assume no obligation
to update or revise forward-looking statements to reflect new events or
circumstances.

Source: Arrowhead Pharmaceuticals, Inc.

View source version on businesswire.com: https://www.businesswire.com/news/home/20181211005916/en/

Source: Arrowhead Pharmaceuticals Inc.

Arrowhead Pharmaceuticals, Inc.
Vince Anzalone, CFA
626-304-3400
ir@arrowheadpharma.com

Investors and Media:
LifeSci Advisors, LLC
Brian Ritchie
212-915-2578
britchie@lifesciadvisors.com
www.lifesciadvisors.com