Ann: PharmAust Canine Trial Update, page-21

As regards the recruitment rate and "Why has it taken so long to locate 25 dogs for PAA's Trial??"
I expect that this is in large part due to the number of dogs eligible to participate.
The UQ study involved "... dogs who have melanoma, mast cell tumours or other cancers which can be injected from the skin’s surface for the trial...” https://www.uq.edu.au/news/article/2021/02/dogs-cancer-needed-immunotherapy-trial
Because we're only interested in B-cell lymphoma - one of the most aggressive cancers - the potential participant pool is far smaller and recruitment is slower as a consequence. We also only want to recruit those dogs in whom the cancer has been picked up early.
So why B-cell lymphoma?
Well, the rapid rate of progression of this cancer means that, by day 28, it's more likely that drug effects on disease progression will be discernable.
It's similar to the MND trial.
As Dr Susan Mathers mentioned in the webinar, nerve cell inflammation/damage thought to be caused by protein aggregation features in other neurodegenerative diseases - for example alpha-synuclein in Parkinson's, Amyloid-β in Alzheimer's - but the rate of progress in these diseases means that any study would need to be of a far longer duration to discern a clinical benefit.
I think everyone would love for the canine trial to move more quickly, but I think the comparison with the UQ study is apples and oranges.
Also worth keeping in mind that, while the current study is focused on B-cell lymphoma, there are good reasons to expect that MPL would be beneficial in other types of cancers - remember the anecdotal accounts from @Mickey Mouse of the other (first) Bella being administered MPL as Zolvix by her owner for what was diagnosed by her vet as a soft tissue sarcoma - which means that the eventual market for MPL as a veterinary drug is likely to be far larger than B-cell lymphoma.

Cheers

Densy