Stem Cell Therapies in Parkinson’s Disease: Are We Moving Too Fast?

[psaffie]

This week, two of my patients asked me about stem-cell therapy for Parkinson’s disease after hearing that Japan had approved it as a promising treatment.

That worried me a lot. My concern is that patients may develop expectations that move ahead of the evidence. I understand that recent iPSC-based work from Japan is technically sophisticated, and early results have been encouraging. But the move toward conditional, limited approval has also raised concerns given the very small clinical evidence base.

We have been here before. Earlier fetal graft studies also showed early improvement, yet longer follow-up revealed graft-induced dyskinesias, and later post-mortem studies found Lewy body pathology within transplanted neurons, raising the possibility of host-to-graft disease propagation.

So my question is not whether cell therapy is promising. It is whether we have sufficiently addressed the lessons of the past to justify the current pace.

For clinicians: how are you counseling patients who ask about these studies now?

For scientists : what would responsible progress look like here—longer mandated follow-up, international registries, stricter endpoints, better mechanistic data before broader access?

I would genuinely like to hear how others in the community are thinking about this.

[gginnan]

Hi @psaffie, thank you for sharing! Managing patients’ expectations regarding novel, albeit promising, treatments is a crucial dimension of patient care. I’m tagging below some community members to see if anyone else has insight into these (or similar) situations, both from the clinician perspective (how are you counseling patients who ask about these studies?) and the researcher side (what would responsible progress look like here?).

@anajimenahdz @ajbilson @Vidash @angelarempela @Anupa @mariam_isayan @mchaparro @peixott @RD_1 @Until @VidyadharaDJ @Stapapou @RLWilliamson @Francisac @bmbrown317 @ara8 @dkflin @J.G @lmaoliveira @Mpambo @Kenlizzette @martab @NHatcher114

[anajimenahdz]

Hi Paula!

I loved this post when I originally read it because it’s such a complex topic, yet a necessary talk we must have in terms of our responsibility with patients when we work in this field, and they, with genuine curiosity and hope, come to us because they trust us as scientists who know the condition they live with.

I, as a general physician who mostly addressed patients regarding clinical/genetic research activities during my previous job, didn’t face these situations daily. Although I think it is our duty to learn the theoretics of CTs, review the methodology of these publications thoroughly so we can understand the shortfalls of making statements/running inaccurate conclusions regarding investigational therapies/interventions.

Having said that, if being exposed to patients, I would have some slides previously prepared to try to explain to them in plain and non-technical language what they should understand to draw their own conclusions regarding those treatments (even more nowadays with fake news all over the place through the internet).

As a scientist, I do believe that all of those you’ve mentioned (I’m attaching the Framework to Assess the Risk of Gene Therapy-Related Delayed Adverse Events by the FDA). Specifically regarding stricter endpoints and better mechanistic data, we should focus on the minimal clinically important difference (MCID) rather than on crude instrument/scale scores; and as clinical researchers, too, it is our responsibility to keep investigating the MCID for clinical assessment instruments that we use on our own cohorts.

Plus, I’d love authors/industry companies to be held accountable, and they should create/submit educational/informative material for patients so they can understand the meaning and limitations of the studies. On the other hand, journals should incorporate this requirement for CT publications. Even as local IRB/ethics committees, they should ask for this follow-up commitment from CT sponsors with research participants enrolled in their studies.

This may seem like a lot of extra work for both industry companies/sponsors and journals, but, in my opinion, that’s the least they can do for the sake of knowledge, science, and the primary target of our research: people living with Parkinson’s disease.