Exhibit 99.1

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PTC Therapeutics Provides Corporate Update
and Reports First Quarter 2026 Financial Results  
  

– First quarter 2026 total revenue of $273 million, including $226 million of product revenue, supporting full-year 2026 guidance raise –

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– Global Sephience™ (sepiapterin) launch momentum continues with first quarter 2026 revenue of $125 million, representing 36% quarter-over-quarter growth –

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– Positive topline results from 24-month interim analysis of PIVOT-HD extension study of votoplam, supporting ongoing global Phase 3 INVEST-HD study and potential regulatory interactions –

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– Open-label vatiquinone registration study to be initiated in Q3 2026 based on FDA feedback –

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WARREN, N.J., May 7, 2026 – PTC Therapeutics, Inc., (NASDAQ: PTCT) today announced a corporate update and financial results for the first quarter ended March 31, 2026.  

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“We are off to a strong start to 2026 with outstanding revenue performance this quarter that supports raising our full-year product revenue guidance,” said Matthew B. Klein, M.D., Chief Executive Officer. “The Sephience launch continues to be strong, with sustained momentum in the US and growing momentum internationally as more countries contribute to the global launch.”

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Key Corporate Updates  

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First Quarter 2026 Financial Highlights

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PTC Updates Full-Year 2026 Financial Guidance

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Non-GAAP Financial Measures

In this press release, the financial results of PTC are provided in accordance with GAAP and using certain non-GAAP financial measures. In particular, the non-GAAP R&D and SG&A expense financial measures exclude non-cash, stock-based compensation expense. These non-GAAP financial measures are provided as a complement to financial measures reported in accordance with GAAP because management uses these non-GAAP financial measures when assessing and identifying operational trends. In management's opinion, these non-GAAP financial measures are useful to investors and other users of PTC's financial statements by providing greater transparency into the historical and projected operating performance of PTC and the company's future outlook. Non-GAAP financial measures are not an alternative for financial measures prepared in accordance with GAAP. Quantitative reconciliations of the non-GAAP financial measures to their respective closest equivalent GAAP financial measures are included in the table below.

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PTC Therapeutics, Inc.
Consolidated Statements of Operations
(in thousands, except share and per share data)

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PTC Therapeutics, Inc.
Summary Consolidated Balance Sheets
(in thousands, except share data)

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PTC Therapeutics, Inc.

Reconciliation of GAAP to Non-GAAP
Projected Full Year 2026 R&D and SG&A Expense
(in millions)

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Acronyms

CHF: Confoederatio Helvetica Francs (Swiss francs)

cUHDRS: Composite Unified Huntington's Disease Rating Scale

DMD: Duchenne muscular dystrophy

FA: Friedreich’s ataxia

FDA: US Food and Drug Administration

GAAP: Generally Accepted Accounting Principles

HD: Huntington’s disease

mFARS: Modified Friedreich’s Ataxia Rating Scale

NDA: New Drug Application

NfL: Neurofilament light chain

nmDMD: Nonsense mutation Duchenne muscular dystrophy

PKU: Phenylketonuria

R&D: Research and Development

SG&A: Selling, General, and Administrative

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Today's Conference Call and Webcast Reminder

To access the live webcast, please visit the “Events & Presentations” page within the Investors section of the PTC website. A replay of the webcast will be available on the PTC website for 30 days following the event. To participate via phone, please register in advance here to receive dial-in details.

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About PTC Therapeutics, Inc. 
PTC is a global biopharmaceutical company dedicated to the discovery, development and commercialization of clinically differentiated medicines for children and adults living with rare disorders. PTC is advancing a robust and diversified pipeline of transformative medicines as part of its mission to provide access to best-in-class treatments for patients with unmet medical needs. The company's strategy is to leverage its scientific expertise and global commercial infrastructure to optimize value for patients and other stakeholders. To learn more about PTC, please visit www.ptcbio.com and follow on LinkedIn, X, Facebook and Instagram.

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For more information please contact:

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Investors:
Ellen Cavaleri
+1 (615) 618-8228
ecavaleri@ptcbio.com

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Media:
Jeanine Clemente
+1 (908) 912-9406
jclemente@ptcbio.com

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Forward-Looking Statements:

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. All statements contained in this release, other than statements of historic fact, are forward-looking statements, including the information provided under the heading "PTC Updates Full-Year 2026 Financial Guidance", including with respect to (i) 2026 total product revenue guidance and total revenue guidance and (ii) 2026 GAAP and non-GAAP R&D and SG&A expense guidance, and statements regarding: the future expectations, plans and prospects for PTC, including with respect to the expected timing of clinical trials and studies, availability of data, regulatory submissions and responses, meetings with regulatory agencies, commercialization and other matters with respect to its products and product candidates; PTC's strategy, future operations, future financial position, future revenues, projected costs; and the objectives of management.

Other forward-looking statements may be identified by the words, "guidance," "plan," "anticipate," "believe," "estimate," "expect," "intend," "may," "target," "potential," "will," "would," "could," "should," "continue," "aim," and similar expressions.

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PTC's actual results, performance or achievements could differ materially from those expressed or implied by forward-looking statements it makes as a result of a variety of risks and uncertainties, including those related to: the outcome of pricing, coverage and reimbursement negotiations with third party payors for PTC's products or product candidates that PTC commercializes or may commercialize in the future; expectations with respect to Sephience, including any regulatory submissions and potential approvals, commercialization, and the potential achievement of sales milestones and contingent payments that PTC may be obligated to make; PTC's ability to maintain its marketing authorization of Translarna for the treatment of nmDMD in geographies in which it has been approved and the effect of the European Commission's adoption of the negative opinion from the Committee for Medicinal Products for Human Use (CHMP) on Translarna and the withdrawal of the Translarna NDA in the US on other regulatory bodies; expectations with respect to PTC's license and collaboration agreement with Novartis Pharmaceuticals Corporation for votoplam for the treatment of Huntington's disease including its right to receive development, regulatory and sales milestones, profit sharing and royalty payments from Novartis, the design and expected timing of clinical trials and studies, the availability of data, and regulatory submissions and responses, including potential accelerated approval; expectations with respect to Upstaza/Kebilidi, including commercialization, manufacturing capabilities, and the potential achievement of sales milestones and contingent payments that PTC may be obligated to make; expectations with respect to vatiquinone, including with respect to the design and expected timing of clinical trials and studies, the availability of data, and regulatory submissions and responses and potential approvals and other matters; expectations with respect to the commercialization of Evrysdi under PTC's SMA collaboration; expectations with respect to the commercialization of Tegsedi and Waylivra; significant business effects, including the effects of industry, market, economic, political or regulatory conditions; changes in tax and other laws, regulations, rates and policies; the eligible patient base and commercial potential of PTC's products and product candidates; PTC's scientific approach and general development progress; PTC's ability to satisfy its obligations under the terms of its lease agreements; the sufficiency of PTC's cash resources and its ability to obtain adequate financing in the future for its foreseeable and unforeseeable operating expenses and capital expenditures; and the factors discussed in the "Risk Factors" section of PTC's Annual Report on Form 10-K, as well as any updates to these risk factors filed from time to time in PTC's other filings with the SEC. You are urged to carefully consider all such factors.

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As with any pharmaceutical under development, there are significant risks in the development, regulatory approval and commercialization of new products. There are no guarantees that any product will receive or maintain regulatory approval in any territory, or prove to be commercially successful, including Sephience, Translarna, Emflaza, Upstaza, Kebilidi, Evrysdi, Tegsedi or Waylivra.

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The forward-looking statements contained herein represent PTC's views only as of the date of this press release and PTC does not undertake or plan to update or revise any such forward-looking statements to reflect actual results or changes in plans, prospects, assumptions, estimates or projections, or other circumstances occurring after the date of this press release except as required by law.