One of the reasons I'm excited about PTX-200 playing a crucial role in CellPryme A and CellPryme-M is that it allows Prescient to extract maximum value from this asset.
There are a number of reasons why it is unlikely that PTX-200 will be progressed further by Prescient in the current relapsed/refractory AML program.
The first is that Prescient now has a second clinical program in AML, albeit aimed at different targets. It doesn’t make sense to me for a small biotech with limited resources to have two programs in the same indication.
Secondly, although PTX-200’s results to date have been encouraging, with a number of Complete Remissions seen, I anticipate that we will see these result eclipsed by cell therapy treatments, hopefully including PTX’s OmniCAR AML candidate.
A third obstacle to PTX-200’s progression, and the one most stressed by SYC in his recent presentation, is the changing competitive landscape. There is now less unmet need in AML than when Prescient commenced its clinical program. As SYC explained, while there was little advance in AML treatment for four decades, there have been 8 new therapies approved by the FDA for AML since when PTX commenced its Phase 1/2 trial in AML in 2016.
In addition to more approved therapies, there is a large number of drugs in development for AML. There are over 130 cell therapy programs alone in this indication (see 2022 Global Data graph below) and over 540 clinical trials. An even better picture of the situation can be seen in the second graph below, Insights from Heme Malignancies, from a Cancer Progress convention held in New York in May, 2019. This graph overlays the number of drugs in development in the different heme cancers vs. US market size, determined by disease incidence. The AML pipeline stands out as being the most excessive, relative to market size. This contrasts with PTCL (in which PTX-100 is currently being assessed) which can also be seen in the same graph. As well as having fewer programs in development for PTCL, there are fewer FDA approved therapies.
Another consideration with respect to PTX-200 is IP. While PTX-200 commenced Phase 1/2 in relapsed/refractory AML in combination with cytarabine in 2016, it already commenced testing in Phase 1 as a monotherapy in relapsed/refractory AML in 2006. It appears to me that the key US patent here is US20150297621, which has an original filing date of 2004 (patent life is generally 20 years from original filing date). But I could be wrong on this – patent process and law are highly complex.
Taking everything into account, if something has to be culled from Prescient’s pipeline (and, my, isn’t there a lot of pipeline culling happening in the world of biotech and pharma, atm!), it makes sense to me for it to be PTX-200 in AML.
(20min delay)