[Slide Deck] PTC Therapeutics Our Revisit of the Huntington’s Piece in the PTCT Story

Research evidence excerpt

[Slide Deck] PTC Therapeutics Our Revisit of the Huntington’s Piece in the PTCT Story

Executive Summary

With Ph 3 INVEST-HD now underway (initiated by partner NVS) and 24-month Ph 2 data in hand (note) for

votoplam (oral HTT mRNA splicing modulator), we provide a reference deck to capture the key evidence and

assess the potential approval timelines.

In this deck, we: What to Watch in the Next 12 to 18 Months?

1. Summarize what is known • INVEST-HD execution: Enrollment pace could give more clarity on timelines.

about the votoplam program

and competitors to date • Interim analysis details: Trigger, efficacy/futility criteria, and whether it informs

any regulatory strategy (e.g., can data be used in an AA submission).

2. Outline potential timeline

scenarios • Regulatory path color: AA vs. full approval framing. Clarity could offer a lever

for NT upside considering Makary’s recent departure at the FDA.

3. Determine the potential

commercial opportunity in HD, • PIVOT-HD longer term data: Longer term durability could help reduce Ph 3’s

anchored in addressable clinical risk.

population and penetration • Competitive catalysts: Readouts and regulatory updates from competitors that

dynamics could translate to votoplam.

Key Votoplam Characteristics:

• Targets the Underlying Cause of the Disease. Potential to improve disease progression significantly vs. SoC which targets the

underlying symptoms not mutant HTT (mHTT) levels directly.

• Validated Splicing Platform: Votoplam, announced originally in 2020 (link), was discovered using the same RNA splicing

platform that produced Evrysdi (risdiplam) for SMA, providing a successful and validated precedent for this platform

technology.