Prilenia announce results from the PROOF-HD study: Promising, but mixed results!

Today, April 25th, Prilenia announced results from the PROOF-HD clinical trial for Huntington’s Disease. Some of the participants showed significant benefits from the Pridopidine drug, while others did not benefit at all. 

This is promising because for the first time we have a drug that demonstrates effect on disease progression, cognitive and motor symptoms.  – This is a wonderful step forward, says Astri Arnesen, President of EHA.  -Nevertheless, the fact that not all the participants who received the treatment had the postive effect, is also somehow disappointing.

Which are the key messages from the Prilenia study results?

“We are moving in the right direction”, says the President of The International Huntington Association, Svein Olaf Olsen. The results of the Prilenia study suggest that their therapeutic approach is safe and that it has benefits on important clinical measures, such as HD motor and cognitive symptoms.

Nevertheless, it’s important to note that the study has shown that you do not get the desired improvement/effect of Pridopidine on HD symptoms if you mix it with other medicines, such as neuroleptics. “But you also have to realize that Pridopidine is not a drug designed to target all the consequences that Huntington’s Disease brings with it”, says Svein Olaf Olsen.

Moreover, the Prilenia trial did not meet its primary endpoint, which was an improvement in functional capacity as measured by the Unified Huntington Disease Rating Scale-Total Functional Capacity, and also did not meet a key secondary endpoint, which was an improvement in the Composite Unified Huntington’s Disease Rating Scale. The company suggests that the lack of a significant effect on these endpoints may be related to the other medicines taken by the trial participants.

In a press release of 25th of April, Prilenia informs:

  • Pre-specified analyses in PROOF-HD, excluding patients on neuroleptics and chorea medications, showed clinically meaningful and nominally significant benefits and improvements from baseline of pridopidine as compared to placebo on disease progression, motor and cognitive outcome measures.
  • Q-Motor, an objective measure of motor function, showed robust beneficial effects for participants treated with pridopidine in PROOF-HD at various time points.
  • In both PROOF-HD and the HEALEY ALS Platform trial, pridopidine was well-tolerated with no serious treatment-related adverse events.
  • However, PROOF-HD primary endpoint (Unified Huntington Disease Rating Scale-Total Functional Capacity) and the key secondary endpoint (Composite Unified Huntington’s Disease Rating Scale) did not reach statistical significance, with the effect masked by concomitant medications.
  • The Company is committed to advancing pridopidine in Huntington’s disease and amyotrophic lateral sclerosis (ALS).

What does this mean for the HD community? Will we get a medicine on the market?

“It is far too early to draw a final conclusion”, says Svein Olaf Olsen. “HD is a complex disease, with multiple and impactful features. The fact that Pridopidine did not show improvements on all fronts, means that the company is certainly not completely satisfied with the result. But maybe the expectations were a bit high. So, we will not get a drug that solves all HD symptoms or is able to stop the disease, but we may get a medicine that can help, for instance, to alleviate some of the cognitive or motor changes associated with the disease. And this is good news”, says Olsen.

“This is similar to the cancer treatment quest, since you still don’t have a pill that helps with all types of cancer. But we are in the process of developing new therapeutic drugs for HD. We are on our way”, adds Olsen.

Are you disappointed?

“Not at all. I had hoped for something more. I, like all my friends, hoped for “The final cut!” “The final solution”. I am convinced that one day you will get a pill or an injection to cure HD, but perhaps in the beginning the HD treatment will be more like a mix of different drugs and we will get medicines that are not suitable for everyone. The most important point in the press release from Prilenia is that we have a drug that can be helpful. And for sure the company will continue its hard work to get the drug into the market”, concludes Svein Olaf Olsen.

Learn more about PROOF-HD study