1.JB, I 100% agree withthegeneral statement made through and by MSBthat MSC's have the abilitytoalterINF Gamma levels,in Vitro. 100%. Agreed.2.This CMC slide, in lot 1, showsa change in INFy from 3000 pg/ml, up to approximately 4000 pg/ml ( a33% increase ) , and a decrease to approximately 10% to 2800 in Lot2. I cannot draw the same conclusion that INF Gamma increased, whenthe slide shows it also decreased, in a sample size of 2.
Re1. It’s not just one “general statement made through and byMSB” (your words). I’ve shown three.
1) A Kasikis et al2021 statement - “MSCs”.. “reduce”.. “INF Gamma”
Sentence source indocument – page 2o2 2ndsentence in para 2.
Cited authority –Aggarwarl and Pittenger 2005.
2) A statement inthe TNFR1 patent application (June 2021) “MSCs decrease” “INFGamma”
Sentence source indocument – page 4o14 para [0004]
Cited authority –Aggarwarl, 2005 (but no full paper titles are listed in patent pdf Ihave)
3) A statement inMSB’s ODAC Briefing paper (Aug 2020) “..MSCs” “decreasing”“IFN Gamma”
Sentence source indocument – page 11o127 line 9.
Cited authority - Aggarwarl and Pittenger 2005
Yes or no? True orfalse?
The general statement MSB made was:
"A multitude of published data from independent laboratories demonstrate that ce-MSC's in vitro and in vivo exhibit a broad range of immunomodulatory actrivities"
MSB then quoted what these other laboratories found as an example of broad range of immunomodulatory activities.
And they don’tjust say “alter” (your word) without specifying a direction. Theyspecifically say MSCs decrease or reduce INF Gamma levels.
Yes - the 2005 paper referenced claims that MSC's reduced the INF Gamma levels down specifically.
Yes or no?
Mesoblast on the other hand, did not claim this with their cells.
Re2. I agree withyour observations on the size and direction of the two samples. But..
You wrote “Icannot drawthesameconclusionthat INF Gamma increased, when the slide shows italso decreased, in a sample size of 2.”
By using the wordthe same as you have you make your sentence confusing to me – sameas what?
Are you implyingI’ve already concluded on the basis of a sample of two that INFgamma increases generally? – If so I haven’t concluded that (menoting an inconsistency isn’t me drawing a conclusion on the basisof two data points).
The general statements from MSB you’ve agree100% with (re 1) but you used the wordalter, not decrease didn’tspecify or suggest an increase – they, taken together would havesuggested a decrease was generally to be expected.
So you can’t bedrawing the same conclusion as either me (as I didn’t draw thatconclusion as a conclusion yet and like you wouldn’t on the basisof two samples) nor MSB who statements (re 1) should have caused youto expect no increase.
I’m assuming you put the word same in yoursentence because you’ve anticipated (incorrectly) what you thoughtI’d concluded rather than just have your side of the conversation.But if same refers to something else - I'm all ears.
I’m not asking youto conclude anything general on the basis of a sample of two.
What I was wantingwas for you to acknowledge that there is an inconsistency between thethree MSB statements above and one of the two offered remestemcel-Llot samples in CC-16 in terms of the direction – the three generalstatements suggest MSB had a general view at the times of thosepublications (that's in 2020, 2021, 2021) that MSCs will decrease INF gammalevels and yet one of the specific lots shows an increase. To me thatis just a clear fact.
Do you see thatinconsistency? Yes or no?
Yes - the inconsistency between a 2005 in vitro test that gave a conclusion, and the CMC data from MSB, which is a seperate in vitro test which both agreed and disagreed with the 2005 conclusion, and MSB's acknowledgement that their product does not reduce Interferon Gamma levels is very clear.
As to the why that is the case, that is the unknown part of the science right now. Nobody appears to know exactly what and how these cells operate. If they did, we would already have approved treatments already.
Getting back to the crux of your initial point was concern that the FDA may have an opinion on the fact that INF Gamma increased in the CMC data that MSB provided. Given that MSB has not claimed anywhere that their product is working to decrease the levels of INF Gamma, I simply do not see how you can draw that connection. Even on mesoblasts own slide it acknowledges that their cells did not affect the INF Gamma levels.
This is cut and paste from the ODAC briefing slides:
A multitude of published data from independent laboratories demonstrate that ce-MSC's in vitro and in vivo exhibnit a broad range of immunomodulatory actrivities( de Castro et al, 2019 English
et al, 2009; Ghannam et al, 2013; Giri et al, 2020; Németh et al, 2009; Ramasamy et al, 2007;
Rasmusson et al, 2005). Consistent with these published findings, data generated during early
development of remestemcel-L provided evidence that ce-MSCs have immunomodulatory
properties and a multimodal mechanism of action which may have therapeutic benefit in the
treatment of aGVHD. Culture-expanded MSCs demonstrate immunosuppressive activity in T
cell-driven immune responses in animal models of allogenic skin graft rejection (Bartholomew et
al, 2002). In vitro, ce-MSCs suppress T cell activation and proliferation in response to alloantigenic and mitogenic challenge and, in addition, stimulate an increase in regulatory T cells
(Treg) (Aggarwal & Pittenger, 2005; Klyushnenkova et al, 2005). In co-culture systems, ceMSCs alter the cytokine secretion profile of immune cells (dendritic cells, naïve and effector T
cells, NK cells), decreasing expression of proinflammatory cytokines (eg, interferon-gamma
[IFNγ], TNFα) and increasing secretion of anti-inflammatory cytokines (eg, interleukin-4 [IL-4]
and interleukin-10 [IL-10]) (Aggarwal & Pittenger, 2005). The immunomodulatory effects of ceMSCs on activated T cells are attributable, at least in part, to secretion of paracrine factors such
as prostaglandin E2 (PGE2) in response cues in the inflammatory environment (Aggarwal &
Pittenger, 2005). Data show that ce-MSCs secrete increased levels of PGE2 when co-cultured
with activated peripheral blood mononuclear cells and when directly stimulated with TNFα
(Aggarwal & Pittenger, 2005; data on file).
That entire paragraph above is in support of the leading statement at the beginning of the paragraph, to show that other independent laboratories have discovered immunomodulatory activities coming from the MSC's.
The next paragraph:
Shown below are immunomodulatory effects of Mesoblast’s ce-MSC product, remestemcel-L,
on proliferation of activated T cells and on suppression of macrophage and T cell-derived
inflammatory cytokines. When co-cultured with allogeneic peripheral blood mononuclear cells
(PBMC) where the T cells have been activated with anti-CD28 and anti-CD3 mAbs,
remestemcel-L lots manufactured from 3 different donors, including lots used in the pivotal
Phase 3 trial, Study GVHD001, and lots generated in process performance qualification(PPQ)
manufacturing runs, potently inhibited T cell proliferation in a dose-dependent manner (CMC
Figure 4 Part A). Suppression of T cell proliferation was maintained in transwell experiments
(CMC Figure 4 Part B), demonstrating that this effect was due to secretion of soluble factors
acting either directly on T cells, such as PGE2, or indirectly, such as MCP-1 or M-CSF, to
induce M1 to M2 macrophage polarization and IL-10 secretion.
Measurement of cytokines produced by the activated PBMC showed significant induction of
TNFα, lymphotoxin and IFNγ, indicative of a cytokine storm (CMC Figure 4 Part C).
Remestemcel-L potently inhibited by over 90% both TNFα and lymphotoxin production, but not
IFNγ, indicating a specific and selective pattern of proinflammatory cytokine suppression (CMC
Figure 4 Part C) within both T cells and macrophages. These data suggest that remestemcel-L
responds to proinflammatory cues in the inflammatory microenvironment by immunomodulatory
mechanisms which create a paracrine loop resulting in specific shut down of inciting
inflammatory cytokines.
So it is clear to me, the immunomodulatory effects Mesoblasts is claiming for their product, because they are stated in that paragraph, and include no reference to the product reducing or increasing INF Gamma. " but notIFNγ, indicating a specific and selective pattern of proinflammatory cytokine suppression"
So for that reason, I do not share your concern at all. They are not claiming their product lowers INF Gamma, and all the results they have obtained were using cells that when tested did not lower INF Gamma.
Finally, you wrote:
3.If this were aproblem, itmusthave already been mentioned in the CRL.Mesoblast has not hinted, nor the ODAC ( which voted 9 to 1 forapproval ) commented, that this was a deficiency, so therefore I dobelieve on the basis that MSB has never made the claim that theircells are selected due the interferon gamma lowering qualities, andthere is no evidence the FDA have decided that lowering interferonGamma is a requirement of an MSC treatment, that they will not berejected on the basis that their cells either lower or raiseinterferon gamma levels ( they did both in the CMC evidence ).
Sorry, I can’ttake this seriously. I’m leaving it in so you know I read it. Yourpost as written I wanted to thank when I first saw it because itlooked like you’d made some genuine human to human concessions to truth. But Iwanted still more agreement – more specific agreement – more detailedagreement than you’d posted – so some simple yes or no, true orfalse replies to my amendments is sought.
No idea what you are on about in that response?
What do these words mean? can’ttake detailedagreement
(20min delay)