Ra Pharmaceuticals Reports First Quarter 2019 Financial Results and Provides Corporate Update

Phase 2 gMG long-term extension data show durability of zilucoplan
treatment effect, with sustained improvements in primary and secondary
endpoints observed at 24 weeks

Initiation of a single, pivotal, 12-week Phase 3 clinical trial in
gMG on track for second half of 2019

Zilucoplan XR achieved rapid and sustained pharmacodynamic inhibition
of complement C5 in non-human primates, supporting once weekly or less
frequent dosing

CAMBRIDGE, Mass.–(BUSINESS WIRE)–Ra
Pharmaceuticals, Inc. (Nasdaq:RARX) today announced financial
results for the first quarter ended March 31, 2019, and provided an
update on recent corporate and clinical developments.

“Zilucoplan’s competitive profile is underscored by the recently
presented results from our Phase 2 long-term extension (LTE) study, in
which clinically meaningful reductions in primary and secondary
endpoints were sustained in patients treated with zilucoplan for 24
weeks,” said Doug Treco, Ph.D., President and Chief Executive Officer of
Ra Pharma. “As an accessible and convenient self-administered therapy,
zilucoplan offers the potential to deliver complement inhibition to a
broad population of patients with generalized myasthenia gravis (gMG).”

Dr. Treco continued: “Building on this momentum, we continue to progress
our zilucoplan life-cycle extension program. The recent presentation of
pre-clinical data for the extended release (XR) zilucoplan program, in
which rapid and sustained pharmacodynamic inhibition of complement
component 5 (C5) was achieved with once-weekly subcutaneous (SC) dosing,
supports our patient-centric approach to the development of convenient
therapies. With initiation of a Phase 2 trial for our second
neuromuscular indication for zilucoplan expected in the second half of
this year, as well as initiation of Phase 1 studies for the zilucoplan
XR program and our oral small molecule C5 inhibitor program expected in
the first half of 2020, we are positioned to build meaningful value as
we advance our mission of expanding access to next-generation therapies
for patients with complement-mediated diseases.”

First Quarter 2019 Highlights and Recent Developments

• In April 2019, Ra Pharma announced the successful completion of
  End-of-Phase 2 interactions with the U.S. Food and Drug Administration
  (FDA) for its Phase 3 clinical trial of zilucoplan in gMG. Based on
  feedback provided by the FDA, the Company plans to initiate a single,
  pivotal, 12-week, Phase 3, randomized, double-blind,
  placebo-controlled trial evaluating the efficacy of a once-daily, SC
  self-administered dose of 0.3 mg/kg of zilucoplan versus placebo in
  the second half of 2019.
• In May 2019, Ra Pharma presented data from its Phase 2 clinical trial
  and open-label LTE study of zilucoplan in patients with gMG at the
  2019 American Academy of Neurology Annual Meeting in Philadelphia, PA.
  In the Phase 2 clinical trial, both zilucoplan doses achieved rapid,
  clinically meaningful, and statistically significant reductions in
  pre-specified primary and secondary endpoints versus placebo at week
  12. In the LTE study, sustained responses were observed for all four
  efficacy endpoints after 24 weeks at the 0.3 mg/kg dose of zilucoplan.
  Placebo patients crossing over to the 0.3 mg/kg dose of zilucoplan
  after 12 weeks experienced rapid, clinically meaningful, and
  statistically significant improvements for all four efficacy endpoints
  from weeks 12 to 24. Treatment with zilucoplan had a favorable safety
  and tolerability profile in the study, consistent with
  previously-completed Phase 1 and Phase 2 studies. There were no
  serious adverse events observed related to treatment with zilucoplan.
• In December 2018, Ra Pharma completed dosing in a Phase 1
  ethno-bridging study in healthy subjects of Japanese and non-Japanese
  descent, enrolling 16 subjects in a multi-dose cohort and 20 subjects
  in a single-dose cohort. Ra Pharma today reports positive results
  from this study, showing that the pharmacokinetic and
  pharmacodynamic profile of zilucoplan was consistent and similar
  across both groups. These results support development of
  zilucoplan for the Japanese market without the need for dose
  modification.
• In April 2019, Ra Pharma presented pre-clinical data for the
  poly(D,L-lactic-co-glycolic acid) XR formulation of zilucoplan at the 6^th
  Annual Peptides Congress in London, UK. Weekly SC doses of the PLGA XR
  formulation of zilucoplan in non-human primates rapidly achieved and
  maintained target drug concentrations for 14 days, sustaining near
  complete pharmacodynamic inhibition throughout this period.

First Quarter 2019 Financial Results

For the first quarter of 2019, the Company reported a net loss of $19.0
million, or a net loss of $0.45 per share (basic and diluted), compared
to a net loss of $16.5 million, or a net loss of $0.61 per share, for
the same period in 2018.

Research and development (R&D) expenses for the first quarter of 2019
were $15.3 million, compared to $13.4 million for the same period in
2018. The increase in R&D expenses for the first quarter was primarily
due to increased headcount and employee-related costs to support
increased research and development activities.

General and administrative (G&A) expenses for the first quarter of 2019
were $4.8 million, compared to $3.3 million for the same period in 2018.
The increase in G&A expenses for the first quarter was primarily due to
increased headcount and employee-related costs and increased expenses
related to our pre-commercial activities.

There was no revenue earned in the first quarter of 2019 or the same
period in 2018.

As of March 31, 2019, Ra Pharma reported total cash and cash equivalents
of $191.6 million. The Company expects that its cash and cash
equivalents will be sufficient to fund operating expenses and capital
expenditures through at least the first quarter of 2021.

About Zilucoplan

Ra Pharma is developing zilucoplan and zilucoplan extended release (XR)
for generalized myasthenia gravis (gMG) and other tissue-based,
complement-mediated disorders with high unmet medical need. The product
candidate is designed for convenient, once-daily, subcutaneous (SC)
self-administration. Zilucoplan is a synthetic, macrocyclic peptide
discovered using Ra Pharma’s powerful proprietary drug discovery
technology. The peptide binds complement component 5 (C5) with
sub-nanomolar affinity and allosterically inhibits its cleavage into C5a
and C5b upon activation of the classical, alternative, or lectin
pathways.

About Ra Pharmaceuticals

Ra Pharmaceuticals is a clinical-stage biopharmaceutical company focused
on leading the field of complement biology to bring innovative and
accessible therapies to patients with rare diseases. The Company
discovers and develops peptides and small molecules to target key
components of the complement cascade. For more information, please
visit: www.rapharma.com.

Forward-Looking Statements

This press release contains “forward-looking statements” within the
meaning of the Private Securities Litigation Reform Act of 1995,
including, but not limited to, statements regarding Ra Pharma’s ability
to expand patient access to important therapies, the potential, safety,
efficacy, and regulatory and clinical progress of Ra Pharma’s product
candidates, including without limitation zilucoplan and our zilucoplan
XR and oral small molecule C5 inhibitor programs, beliefs regarding
clinical trial data, statements regarding trial design, timeline, and
enrollment of Ra Pharma’s ongoing and planned clinical programs,
including without limitation the Phase 3 trial of zilucoplan for the
treatment of gMG and the XR and oral C5 small molecule inhibitor
programs, pending End-of-Phase 2 discussions with regulatory agencies in
the first half of 2019, and the expectation that Ra Pharma’s cash and
cash equivalents will be sufficient to fund operating expenses and
capital expenditures through at least the first quarter of 2021. All
such forward-looking statements are based on management’s current
expectations of future events and are subject to a number of risks and
uncertainties that could cause actual results to differ materially and
adversely from those set forth in or implied by such forward-looking
statements. These risks and uncertainties include the risks that Ra
Pharma’s product candidates, including zilucoplan, will not successfully
be developed or commercialized, in the timeframe we expect or at all; as
well as the other factors discussed in the “Risk Factors” section in Ra
Pharma’s most recently filed Annual Report on Form 10-K, as well as
other risks detailed in Ra Pharma’s subsequent filings with
the Securities and Exchange Commission. There can be no assurance that
the actual results or developments anticipated by Ra Pharma will be
realized or, even if substantially realized, that they will have the
expected consequences to, or effects on, Ra Pharma. All information in
this press release is as of the date of the release, and Ra Pharma
undertakes no duty to update this information unless required by law.

Contacts

Investors:
Ra Pharmaceuticals, Inc.
Natalie Wildenradt,
617-674-9874
[email protected]

Media:
Argot Partners
David Rosen, 212-600-1902
[email protected]