This should 💯 be public information, so I will immortalize it on #nostr in the name of advancing medical research.

2024 was quite a year; quite a few positive developments in the prion science field.

This is from IONIS pharma today:

December 2024

Dear Prion Disease Community,

We are writing today to inform you that Ionis’ Phase 1/2a clinical trial of ION717

(NCT06153966), called PrProfile, in people with symptomatic prion disease has achieved full

enrollment. The purpose of PrProfile is to evaluate the safety, tolerability, pharmacokinetics

and pharmacodynamics of intrathecal (IT) delivery of ION717. While enrollment is now

complete, dosing and data collection will continue for the duration of the trial.

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Ionis also recently updated PrProfile to include a 70-week open-label extension (OLE) period as

part of the trial. Individuals who complete the double-blind placebo control period may

transition into the OLE. All participants will receive ION717 during the OLE. Individuals who

participate in the OLE will continue to be monitored by study doctors.1

Ionis recognizes the considerable time and effort each person with prion disease and their

caregivers have invested and continue to invest by participating in PrProfile. Your courage and

commitment to advancing medical research is truly inspiring. We recognize the urgent need for

advancing treatments and remain dedicated to completing this trial as quickly as possible. Ionis

will provide the prion disease community with updates as appropriate in the future.

Sincerely,

The Ionis ION717 Team

*****

When do you expect results from this clinical trial?

The Primary Completion Date occurs when the last person accepted into PrProfile completes

study related procedures and assessments for the primary outcome measure. With the

enrollment of the final person having just occurred, Ionis can estimate that the Primary

Completion Date to be July 2025. Due to the complex nature of clinical development, this date

is subject to change. If the completion date changes, we will provide an update on

clinicaltrials.gov. 1,2

We will share results from the clinical trial when it is appropriate to do so in the future.

MED-US-PRNP-2400024 v1 11/2024 Page 2 of 2

Why did Ionis add an open-label extension period to PrProfile?

The addition of an OLE is common with trials like this one and is done for many reasons. In the

case of PrProfile, the OLE will enable researchers to collect additional, longer-term data

associated with exposure to ION717.

ION717 remains an investigational medicine only, without any established clinical evidence of

safety or efficacy.

Is there a way to receive ION717 outside the clinical trial, such as for people not eligible for

this clinical trial?

Evaluation of the safety and efficacy of ION717 in clinical trials is essential to establishing

whether ION717 can help people diagnosed with symptomatic prion disease. For this reason,

ION717 is not available outside this clinical trial. We are working diligently to conduct the

clinical trials necessary to evaluate ION717 in individuals with symptomatic prion disease. For

additional information about Ionis’ expanded access policy, which also includes Right To Try and

Compassionate Use, click here.

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The CJD Foundation and CJD International Support Alliance are community resources that

provide education and support to those affected by prion disease.

For more information about Ionis, visit www.ionis.com or email padvocacy@ionis.com.

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