Exhibit 99.1

PTC Therapeutics Provides Corporate Update and
Reports First Quarter 2025 Financial Results  
  

– Strong revenue performance of $190 million – 

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– Positive CHMP opinion for Sephience™ (sepiapterin) received in April 2025, NDA review remains on track for July 29, 2025 PDUFA date –

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– Global Sephience launch activities progressing well –

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– Strong cash position of over $2.0 billion as of March 31, 2025 –

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WARREN, N.J., May 6, 2025 – PTC Therapeutics, Inc., (NASDAQ: PTCT) today announced a corporate update and financial results for the first quarter ended March 31, 2025.  

“Following a year of outstanding execution across every part of the Company, we have built on this positive momentum with solid revenue performance in the first quarter, allowing us to narrow our full-year revenue guidance,” said Matthew B. Klein, M.D., Chief Executive Officer. “Our strong cash balance supports all of our planned commercial and R&D activities and provides the ability to reach cashflow breakeven without raising additional capital. The positive CHMP opinion for Sephience kickstarts our anticipated global launch for what we see as a significant revenue opportunity.”

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Key Corporate Updates:  

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Key Clinical and Regulatory Milestones:  

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First Quarter 2025 Financial Highlights:

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PTC Updates Full-Year 2025 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 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.

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 2025 R&D and SG&A Expense
(In millions)

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Acronyms:

CHF: Confoederatio Helvetica Francs (Swiss francs)

CHMP: Committee for Medicinal Products for Human Use

DMD: Duchenne Muscular Dystrophy

EC: European Commission

FDA: U.S. Food and Drug Administration

GAAP: Generally Accepted Accounting Principles

HD: Huntington’s Disease

HTT: Huntingtin protein

MAA: Marketing Authorization Application

NDA: New Drug Application

NfL: Neurofilament light chain

nmDMD: Nonsense mutation Duchenne muscular dystrophy

PDUFA: Prescription Drug User Fee Act

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 call by phone, please click here to register and you will be provided with dial-in details. To avoid delays, we recommend participants dial in for the conference call 15 minutes prior to the start of the call. The webcast conference call can be accessed on the Investors section of the PTC website at https://ir.ptcbio.com/events-presentations. A replay of the call will be available approximately two hours after completion of the call and will be archived on the company's website for 30 days.

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About PTC Therapeutics, Inc.
PTC is a global biopharmaceutical company focused on the discovery, development and commercialization of clinically differentiated medicines that provide benefits to children and adults living with rare disorders. PTC's ability to globally commercialize products is the foundation that drives investment in a robust and diversified pipeline of transformative medicines and our mission to provide access to best-in-class treatments for patients who have an unmet medical need. The company's strategy is to leverage its strong scientific expertise and global commercial infrastructure to maximize value for its patients and other stakeholders. To learn more about PTC, please visit www.ptcbio.com and follow on Facebook, X, and LinkedIn.

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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 This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995.

Forward-Looking Statements:

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 2025 Financial Guidance", including with respect to (i) 2025 total revenue guidance and (ii) 2025 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, 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," and similar expressions.

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; PTC's ability to maintain its marketing authorization of Translarna for the treatment of nmDMD in Brazil, Russia and other regions; the effect of the European Commission’s adoption of the negative opinion from the Committee for Medicinal Products for Human Use (CHMP) on Translarna on other regulatory bodies; PTC's ability to use the results of Study 041, a randomized, 18-month, placebo-controlled clinical trial of Translarna for the treatment of nmDMD followed by an 18-month open-label extension, and from its international drug registry study to support a marketing approval for Translarna for the treatment of nmDMD in the United States; whether investigators agree with PTC's interpretation of the results of clinical trials and the totality of clinical data from its trials in Translarna; expectations with respect to PTC's license and collaboration agreement with Novartis Pharmaceuticals Corporation including its right to receive development, regulatory and sales milestones, profit sharing and royalty payments from Novartis; 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 Sephience, including any regulatory submissions and potential approvals, commercialization, and the potential achievement of regulatory and sales milestones and contingent payments that PTC may be obligated to make; expectations with respect to vatiquinone, including any regulatory submissions and potential approvals, commercialization, and the potential achievement of regulatory and sales milestones and contingent payments that PTC may be obligated to make; 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 most recent 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.

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 Translarna, Emflaza, Upstaza, Kebilidi, Evrysdi, Tegsedi, Waylivra, Sephience or vatiquinone.

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.