Catabasis Pharmaceuticals Announces Favorable Results for Functional Assessments in the MoveDMD® Trial for Edasalonexent in Duchenne Muscular Dystrophy at the American Academy of Neurology 69th Annual Meeting

— Prespecified Analysis of Part B Data Shows Improvement in Rates of
Change Across Five Functional Assessments —

— Part C Interim Results to be Announced in Q3 2017 —

CAMBRIDGE, Mass.–(BUSINESS WIRE)–Catabasis
Pharmaceuticals, Inc.
(NASDAQ:CATB), a clinical-stage
biopharmaceutical company, today announced additional favorable results
across multiple functional assessments in the MoveDMD trial at the
American Academy of Neurology 69th Annual Meeting. In Part B
of the MoveDMD trial, designed to evaluate the potential of
edasalonexent in the treatment of Duchenne muscular dystrophy (DMD),
numerical improvements were seen in prespecified rate change analyses
across five functional assessments. These results are in addition to and
consistent with the numerical improvements in the same functional
assessments with edasalonexent compared to placebo after 12 weeks of
edasalonexent treatment.

Following our completed analysis of the rate of change data from Part B
of the MoveDMD trial, we are encouraged by the consistency of the
possible treatment effects across the range of functional assessments
after only 12 weeks of dosing as well as the numerical improvements in
functional assessments compared to placebo. These functional assessments
are meaningful to boys affected by Duchenne and are known to correlate
with loss of milestones and disease progression,” said Joanne Donovan,
M.D., Ph.D., Chief Medical Officer of Catabasis. “Coupled with the
reassuring safety, tolerability and plasma exposure data in patients
affected by Duchenne, we are optimistic about edasalonexent’s potential
and look forward to continuing to evaluate it as a novel treatment for
this devastating disease.”

In the MoveDMD trial, functional assessments were performed at baseline
of Part A, at baseline of Part B, which was on average 8 months later,
and at the endpoint of Part B, which was following 12 weeks of
treatment. This design enabled the comparison of changes in functional
ability between an extended off-treatment period and 12 weeks of
treatment with edasalonexent. The MoveDMD trial was not powered for
functional assessments and these analyses were generally not
statistically significant.

  • During the off-treatment period there were declines in average speeds
    of timed function tests (10-meter walk/run, 4-stair climb and time to
    stand) as well as the North Star Ambulatory Assessment (NSAA) and
    Pediatric Outcomes Data Collection Instrument (PODCI) assessment
  • During edasalonexent treatment, positive numerical changes were
    observed across the five functional assessments compared with the
    off-treatment period:

    • Rate of decline slowed by 50% for 10-meter walk/run
    • Rate of decline slowed by 45% for time to stand
    • Rate of decline slowed by more than 50% for 4-stair climb with no
      decline in function
    • Rate of decline in score slowed by more than 50% for NSAA with
      positive improvement seen
    • Rate of decline in score slowed by more than 50% for PODCI
      (p=0.01) with positive improvement seen
    • The edasalonexent 100 mg/kg/day treatment group also showed numerical
      improvement versus placebo across these five functional assessments in
      Part B of the trial. Functional assessments included in this trial have
      precedence as endpoints for pivotal trials in DMD.

      Catabasis’ MoveDMD trial is a three-part clinical trial investigating
      the safety and efficacy of edasalonexent in boys ages 4 – 7 affected
      with DMD (any confirmed mutation). The planned prespecified analyses
      from Part B of the MoveDMD trial included a cross-over comparison to
      evaluate the rate of change for the functional assessments while the
      patients were largely off-treatment (Part A baseline to Part B baseline)
      to the rate of change while on edasalonexent treatment for 12 weeks in
      Part B. This comparison included the twelve boys that participated in
      Part A and then crossed over to edasalonexent treatment in Part B. In
      January 2017, Catabasis reported that the primary efficacy endpoint of
      MRI T2 was not met and numerical improvements were observed for the
      functional assessments with the placebo-controlled comparisons in Part B
      of the trial.

      From Part A of the MoveDMD trial, the Company reported in January 2016
      that edasalonexent was generally well tolerated with no safety signals
      observed and NF-kB target engagement was observed. Consistent with Part
      A, there were no safety signals and edasalonexent was well tolerated in
      Part B of the trial. There were no treatment-related serious adverse
      events, no drug discontinuations and no dose reductions.

      Catabasis intends to report results from Part C, the open-label
      extension part of the MoveDMD trial, in 2017. To allow for all the boys
      participating in Part C to complete 24 weeks of dosing with
      edasalonexent, an interim update on Part C results is now planned for Q3
      2017. Following additional data analysis on functional assessments from
      Part C, the Company will determine the next steps for edasalonexent in
      DMD.

      About Edasalonexent (CAT-1004)
      Edasalonexent (CAT-1004) is
      an investigational oral small molecule that is being developed as a
      potential disease-modifying therapy for all patients affected by DMD,
      regardless of their underlying mutation. Edasalonexent inhibits NF-kB, a
      protein that is activated in DMD and drives inflammation and fibrosis,
      muscle degeneration and suppresses muscle regeneration. We are currently
      conducting the MoveDMD trial, a three-part clinical trial investigating
      the safety and efficacy of edasalonexent in boys ages 4 – 7 affected
      with DMD (any confirmed mutation). The third part of the trial, an
      open-label extension with edasalonexent, is ongoing. The FDA has granted
      orphan drug, fast track and rare pediatric disease designations and the
      European Commission has granted orphan medicinal product designation to
      edasalonexent for the treatment of DMD. For a summary of clinical
      results reported to-date, please visit www.catabasis.com.

      About Catabasis
      At Catabasis Pharmaceuticals, our mission is
      to bring hope and life-changing therapies to patients and their
      families. Our SMART (Safely Metabolized And Rationally Targeted) linker
      drug discovery platform enables us to engineer molecules that
      simultaneously modulate multiple targets in a disease. We are applying
      our SMART linker platform to build an internal pipeline of product
      candidates for rare diseases and plan to pursue partnerships to develop
      additional product candidates. For more information on the Company’s
      drug discovery platform and pipeline of drug candidates, please visit www.catabasis.com.

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      Company’s Annual Report on Form 10-K for the year ended December 31,
      2016, which is on file with the Securities and Exchange Commission, and
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      Contacts

      Investor and Media Contact:
      Catabasis
      Pharmaceuticals, Inc.
      Andrea Matthews, 617-349-1971
      amatthews@catabasis.com