Tag Archives: AADvac1

PSP’s Top 10 of 2025: part 1 of 2

Posted on by

We saw some real progress against PSP in 2025. This post and the next list my top 10 developments from the past year in approximate and very subjective descending order of importance:

  1. AZP-2006, a drug that enhances the breakdown of abnormal tau protein by the cells’ lysosomes, was found to slow the progression of PSP by 64%.  The catch is that even that impressive-sounding result did not reach statistical significance because the trial was too small, having been designed mainly to assess safety.  Furthermore, its design did not exclude the possibility of random bias in the selection of the participants. But the sponsor company plans to start a much larger and better trial in the second quarter of 2026 as part of the PSP Trial Platform.  My blog post on that is here.
  2. A new subtype of PSP has been identified and named PSP-PF. It was formed from chunks of two of the previously known ten subtypes, PSP-frontal and PSP-postural instability.  If confirmed by other researchers, it will probably be the third-most common subtype, and the second-most rapidly progressive.  The discovery could allow the expansion of drug treatment trials, which prefer to enroll rapidly-progressing participants, to include a more people with PSP than just the ~half with PSP-Richardson syndrome. My blog post is here.
  3. The PSP Trial Platform announced that it will start testing a PSP vaccine called AADvac1 in the second quarter of 2026.  Unlike the passively administered anti-tau antibodies that failed a few years ago, this is an active vaccine, meaning that it stimulates the immune system to make its own antibodies. As my May 2025 blog post point out, AADvac1 has given encouraging early results against one large sub-group of people with Alzheimer’s disease.   
  4. CurePSP announced its new Biomarker Accelerator Program, offering grants of up to $500,000 for major projects to identify and characterize diagnostic tests for PSP.  The program will consider applications involving not only markers to distinguish PSP from other disorders, but also those predicting an individual’s course and to assess change in the disease to use as outcome measures in treatment trials and other research.  
  5. Neurofilament light chain, a protein released into the spinal fluid and blood by many kinds of damage to brain cells, accumulated more evidence of its potential as a diagnostic marker of PSP.  Although NfL is the most promising fluid marker for PSP, it’s not quite ready for routine use because of as yet insufficient sensitivity, specificity and consistency across different labs.  Another major outstanding issue is to what extent blood can replace spinal fluid as a test medium.  However, with the publication of each small advance, more research groups and funders become interested.

My next post will cover developments 6-10.

Two new drugs rarin’ to go

Posted on by

Some good news for those seeking to enroll in a PSP drug trial: The PSP Platform (PTP) is scheduled to start enrolling in the first quarter of 2026. The first two drugs will be the AADvac1 and AZP-2006. The first is a vaccine that stimulates the immune system to make its own anti-tau antibodies.  The second boosts the part of the brain’s garbage disposal system most relevant to PSP.

The third drug is still being finalized with its Pharma sponsor and some points in the study protocol await approval by the FDA.  Only then could the results potentially be used to support a new drug application.  These delays explain the start-up postponement from December 1, 2025 listed in ClinicalTrials.gov to early 2026.

As described in more detail in previous posts here and here, the PTP is a group of about 50 centers in the US led by neurologists at UCSF, UCSD and Harvard.  They have created an infrastructure to test up to three drugs simultaneously, each in its own set of 110 participants.  A major advantage of such a plan is that all three trial groups share the same placebo group.  That way, each participant has only a 25% chance of being assigned to placebo.  The other obvious advantage is cost savings, which could lower the bar for a company to give its drug a go.  The trial is heavily subsidized by a grant from the NIH budgeted for about $14.5 million this year and similar amounts annually through 2029. https://reporter.nih.gov/project-details/11160498

The names and locations of the approximately 50 participating sites across the US have not been announced, but those interested should keep an eye on the ClinicalTrials.gov page https://clinicaltrials.gov/study/NCT07173803 or wait a few days and contact the study’s central enrollment center at 213-821-0569 or psp-participate@usc.edu at the University of Southern California. But perhaps the best option is simply to register with CurePSP for updates on the trial’s status.

Reality check: As for most PSP drug trials, the hope is to slow the rate of progression. The PTP is designed to be able to detect a slowing relative to the placebo group of 33% or better over the 12-month period of the trial.  The trial’s design is based on assumption that the drug would not improve the symptoms – it would at best slow down the pace at which they worsen.  But if all goes well, that could mean many months or even a couple of years of good-quality life.  An even better outcome to hope for is that one of the drugs would work well enough to prevent progression altogether (“100% slowing”), maintaining the present level of symptoms for the remainder of whatever would have been the person’s lifespan without PSP. 

A 33% slowing is a very realistic hope. That 100%-slowing scenario is only a distant hope, but one that’s theoretically possible. And hope does matter.

Two new drugs get a platform

Posted on by

This could be the best news ever in the history of clinical drug development for PSP.


Last week, I attended the Global Tau meeting in London as a representative of CurePSP. Plenty of excellent research was presented, but most of it was laboratory work that would be difficult to relate to the direct concerns of most of this blog’s readers. But there were some clinical advances, and here’s a big one.

Dr. Adam Boxer of the University of California, San Francisco is the project leader for the PSP Trial Platform (PTP). My Oct. 27, 2023 post briefly mentioned that the PTP had just been funded by the NIH. A trial platform is an organization, in this case about 50 study sites throughout North America, that invites multiple pharmaceutical companies to simultaneously allow it to test their trial-ready experimental drugs. The big news last week was Dr. Boxer’s announcement identifying the first two drugs and that enrollment should begin in late 2025.

One drug to be tested will be AZP-2006, from Alzprotect, based in Lille, France. It addresses tau accumulation and neuro-inflammation. The other is AADvac1, from Axon Neuroscience, based in Bratislava, Slovakia. It is an active vaccine directed against the tau protein. More on those drugs in a future post. Both will be Phase 2a trials, meaning that the emphasis will be on safety and tolerability, though efficacy will be detectable if it’s dramatic. The PTP has a candidate for a third company/drug in the wings awaiting final contract negotiations.


The double-blind phase for each drug would be 12 months, followed by an open-label phase, where the participants on placebo will be offered active drug. The primary efficacy outcome measure will be a version of the PSP Rating Scale abridged from its original 28 items to the 15 items best suited to daily disabilities.


Advantages of platform trials over traditional single-drug trials:
• Only one central coordination, technical and statistical staff is needed. This makes drug testing more economical in terms of both money and time, lowering the bar for smaller companies to test promising treatments.
• Only one placebo group is needed and more active-drug arms can be added in the future. So, if a traditional trial offers only a 50% chance of receiving active drug, a platform trial testing three drugs would offer a 75% chance of being assigned to active drug.
• Once the platform is up and running, there is no delay for test site recruitment, contracting and training. This further reduces the costs and allows a new drug to be smoothly slotted into a vacated spot.
• It’s possible to make the three drugs’ trial protocols relatively uniform, allowing the results to be compared with greater confidence than would be possible if each had been tested in separate projects.
• The availability of a completed control group facilitates an interim analysis (a peek at the incomplete data under strict confidentiality rules) to determine if continuing that drug’s trial would be futile. If the result is unfavorable, this saves time, money and most important, drug side effect risk for future participants. Such a drug could be withdrawn from the PTP and another drug could take its place.


The other Principal Investigators working with Dr. Boxer are Dr. Anne-Marie Wills at Massachusetts General Hospital, Dr. Irene Litvan at UC San Diego and Dr. Julio Rojas of UCSF. The NIH has committed $70 million over five years to this project and the participating drug companies would also contribute substantially (though much less than if they had mounted trials on their own). Dr. Boxer told me that as of last week, in late April 2025, the NIH funding had not been affected by the recent Federal research budget cuts, but we’re all holding our breath on that.