Cytodyn Inc (CYDY)

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Ricard- R5- and X4-Tropism, Safety Profiles

Ricard, your replies really caused more reading and checking with my science peers. Thank you!

R5- and X4-Tropism

Check your data for MDR patients, 65-70% of them bears the X4 strain, so PRO-140 does not work on these. 70% of R5 is for the general HIV patients population. Some patients have both strains, but upon treatment with PRO-140 the X4 will remain and take over totally.

After that I prepared myself reading this great overview https://www.prn.org/index.php/management/article/hiv_tropism_1002 (highly recommended)
I further just debated this with science friends.

Your claim that after suppressing CCR5 co-receptor and hence R5-tropic virus, the X4-tropic virus may take over has no evidence in publications. What is known is that lower CD4 receptor count and hence destruction of T cells immunology is a strong independent predictor for X4 tropism.
There are also stats showing that patients with progressed HIV-1 eventually reach this point, i.e. low CD4 count and immune system towards X4 tropism. The sad endgame.

However, there is no study known to us yet which shows that suppressing CCR5 co-receptor will lead to (evolutionary) selective pressure to favor X4-tropism. And this is the key point of our interest here.
Referenced article gives the example of a stem cell transplant which was CCR5-?-32 homozygous, after which he was declared “functionally cured.”
The thesis herein is that a successful CCR5 co-receptor suppression shall not even lead to a devastating lower CD4 count and hence shall not lead to the destruction of the immune system. Therefor such treatment shall not give in to the X4 strain.
This thesis has also being proven via Pro 140 treatment for over two years, where patients didn't develop a change in co-receptor (to X4) tropism! (See CROI poster etc).

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Safety Profiles

We have to check on the working method of IZ more, since blocking the CD4 primary receptor's natural (ligand) operations would suppress body's overall immune response. So far, it seems that IZ is not blocking CD4 directly, but its inter-operation with its co-receptors CCR5 or CXCR4.
One IZ patients showed an Immune Reconstitution Inflammatory Syndrome (IRIS) and FDA recommends further analysis. This is of course a low SAE count.
https://www.aidsmap.com/Immune-reconstitution-inflammatory-syndrome/page/1729559/
https://academic.oup.com/jac/article/65/9/1839/722910
https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/761065lbl.pdf

Pro 140 itself allows CCR5 co-receptor's normal (ligand) operations and therefor no SAEs are to be expected nor shown so far.

We like to look this up in more detail within the next days.
An optimistic view for IZ as well would be having a similar great safety profile.


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Conclusion so far
It is great to have more than one safe treatment for HIV-1, that is for sure. While this matter has been researched for year, T cell (co-)receptor suppression treatment is just about to enter a greater population. Working method is somewhat understood, but more details and long term exposure is required for full assessment. The latter especially in regards to mutation of tropism and the suppression side effects in the first place.

We don't agree that the CCR5 co-receptor suppression would lead to a takeover effect by X4-tropism, see above.

The more treatments, the merrier.
This is very important for the many HIV-1 patients, it more and more seems to us that pushing certain drugs through the regulatory process has been neglected for a good while.

In this sense, it would be best to buyout or partner with CYDY even at lower evaluation to reduce the time to market by having all required funds needed for a streamlined fast process.