Category Archives: TIM-3

Enumeral update – guest post by Cokey Nguyen, VP, R&D

Paul’s introduction:  Enumeral has been sending ’round some interesting updates to several of their programs and I asked for some more detail. Below is a quick primer sent along by Cokey Nguyen. More detail is available in Enumeral’s recent 8K filings, including one that dropped this morning. Also the company will present this and other work at the AACR Tumor Microenvironment Meeting in January (http://www.aacr.org/Meetings/Pages/MeetingDetail.aspx?EventItemID=73#.VlyGS7_QO2k - see below).

New data from Enumeral, by Cokey Nguyen

PD-1 biology in human lung cancer is an active area of research, as these cancers have shown PD-1 blockade responsiveness in clinical trials.  Enumeral has a drug discovery effort aimed at generating novel anti-PD-1 antibodies to develop into potential therapeutic candidates.  Using a proprietary antibody discovery platform, two classes of PD-1 antagonist antibodies were discovered:  the canonical anti-PD-1 antibody which blocks PD-L1/PD-1 interactions and a second class of antibody which is non-competitive with PD-L1 binding to PD-1.  These antibodies were validated first in a pre-clinical model of NSCLC using NSG mice with a humanized immune system and a patient derived NSCLC xenograft (huNSG/PDX) (Figure 1).  Here either class of antibody demonstrated activity on par with pembrolizumab, confirming that PD-1 blockade can slow tumor growth.

Figure 1

Figure 1

In order to confirm these pre-clinical findings, Enumeral began proof of concept studies with NSCLC samples.  The first question was if resident TILs, as found in tumors, could be reinvigorated (Paukken and Wherry, 2015) or if PD-1 blockade is mainly a phenomenon that affects lymph node-specific T cells that have yet to traffic to the tumor.  In these studies, Enumeral found PD-1 blockade can, in fact, increase effector T cell function, as readout by IFNg, IL-12, TNFa and IL-6.  In addition, in a NSCLC sample that showed PD-1hi/TIM-3lo expression, PD-1 blockade strongly upregulated TIM-3 expression (~5% to ~30%, see Figure 2).

Figure 2

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In these NSCLC-based studies, it was also found that an anti-PD-1 antibody (C8) which does not bind to PD-1 in the same manner as nivolumab or pembrolizumab (PD-L1 binding site) displays differentiated biology:  increased IFNg production and significantly higher levels of IL-12 in these bulk (dissociated) tumor cultures (Figure 3).  As IL-12 is thought to be a myeloid derived cytokine, this mechanism of action is not yet well understood, but has been now observed in multiple NSCLC samples as well as in MLR assays.

Figure 3

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In these NSCLC studies, while a subset of patient samples demonstrates PD-1 blockade responsiveness, the co-expression of TIM-3 on NSCLC TILs suggests this is a validated path forward to increase the response rate in lung cancer.  As with the PD-1 program, armed with a substantial portfolio of diverse anti-TIM-3 binders, Enumeral is actively testing single and dual checkpoint blockade on primary human lung cancer samples.

Look for the companies 2 posters at AACR/TME in January

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“Combination Cancer Immunotherapy and New Immunomodulatory Targets” published in Nature Reviews Drug Discovery

Part of the Article Series from Nature Reviews Drug Discovery, our paper hit the press today

Combination cancer immunotherapy and new immunomodulatory targets. Nature Reviews Drug Discovery 14, 561–584. 2015.  doi:10.1038/nrd4591

by Kathleen Mahoney, Paul Rennert, Gordon Freeman.

a prepublication version is available here: nrd4591 (1)

ICI15 presentation is now available

Over 100 slides on immune checkpoint combination therapy, novel targets and drug development in immuno-oncology, created for a 3 hour workshop at ICI15 (link).

As always we work from indications to discovery and back again, keeping one eye on the rapid evolution of clinical practice in oncology and the other on novel targets and therapeutics.

on SlideShare now:

In Consideration of TIM-3

Slide1

There is nothing like hearing science told by passionate and talented investigators, and we got a one-two punch on the subject of TIM-3-mediated immunotherapy from Drs Vijay Kuchroo and Ana Carrizosa Anderson at the ImVacS Immunomodulatory Antibodies for Cancer meeting in Boston on Monday, August 11. The image above is modified from this review, written by the speakers.

Having sent a few years tackling this challenging protein family it was refreshing to see the utility of anti-TIM-3 therapy being supported by robust experimentation. This is a complex story and one that’s hard to get right, but I think these investigators from Harvard Medical School are getting very close.

Let’s have a look.

Vijay Kuchroo introduced several unifying hypotheses – first, that TIM-3 is always co-expressed on T cells along with PD-1, thereby marking such T cells as anergized or exhausted (in any case, non-responsive to TCR-stimulation), and second, that TIM-3 functions as a cell death signal for T cells. The first hypothesis is supported by the literature, and likely portrays the consensus view. The second hypothesis was supported by experiments in which isolated T cells were exposed to soluble Galectin-9 (Gal-9) whereupon these T cells “blew apart” as shown in a short video. This latter hypothesis is apt to be more controversial, as the experimental conditions used are probably not physiological, and the described effect is not anticipated in the Gal-9 literature. Regardless, it was impressive data. It is possible that there is some interplay between TIM-3 binding to Gal-9 and TIM-3 binding to phosphatidylserine (PS) that regulates T cell responses. That’s not been worked out yet. Gordon Freeman later offered the additional hypothesis that Gal-9 serves to attenuate or modulate TIM-3 signaling, perhaps in cis (on the same cell) or trans (across cells).

Dr Kuchroo then presented some very interesting new data that tumor stromal cells produce IL-27 that induces T cell suppression and supports T regulatory cells (Treg). IL-27 therefore emerges as a novel regulator of the tumor Treg environment. The “exhaustion module” was further articulated as follows: the tumor stroma secretes IL-27 that signals through the IL-27 receptor to PRDM1. PRDM1 induces the upregulation of TIM-3, LAG-3, PD-1 and IL-10. Additional new targets were identified using this model, and we can look forward to seeing those described in future – that was very nice work. Conversely, IFNy is upregulated when PD-1 and TIM-3 are blocked, e.g. with antibodies. Since interferons, including IFNy, are known to upregulate PD-L1 (the PD-1 ligand) on tumor cells, a particularly attractive therapy might be a combination of anti-TIM-3 and anti-PD-L1 antibodies. Of note, tumor growth and the development of Tregs is deficient in IL-27R gene-deficient (KO) mice, supporting the exhaustion module model. The inhibition of tumor growth in these KO mice is correlated with increased expression of IL-2, TNF and IFNy in the tumor-draining lymph nodes.

One question was raised which addressed how this model could be reconciled with the finding by Steven Rosenberg and others that PD-1 expression marks activated tumor infiltrating lymphocytes (TILs). The difference may be related to the co-expression, or lack of expression, of TIM-3 and perhaps LAG-3. It would appear that we need a way to characterize the diverse variety of T cells found in tumors, beyond the current TILs and Tregs.

Ana Carrizosa Anderson further discussed TIM-3 expression on TILs and showed that TIM-3+ TILs secrete IL-10 and are therefore Tregs. Such TIM-3+ Tregs are preferentially enriched in tumors, pointing to the active induction as described by Dr Kuchroo. Dr Anderson further showed that anti-PD-L1 plus anti-TIM-3 antibodies deprogram Tregs, shutting down their immune suppressive pathways including their own target’s expression – thus anti-TIM-3/anti-PD-1 treatment shuts down expression of TIM-3, PD-1 and a host of other immunosuppressive factors, shining a light on a mechanism of feedback regulation in human TILs.

Dr Anderson then raised an interesting question regarding colorectal cancer which has so far proved resistant to immunotherapy (ipilimumab, nivolumab). In a preclinical CRC model, the combination anti-TIM3 and anti-PD-1 worked very well, This led to the intriguing question of whether TIM-3 is particularly useful here because of the very high expression of Gal9 is high in gut. I like the focus on the local environment, which may be useful in addressing primary tumors.

Speaking of the local environment, this is a good time to mention a paper on TIM-4, another PS-binding protein in the TIM family. Terry Strom along with Vijay Kuchroo and colleagues recently described a “fragile” TIM-4+ tissue macrophage population with immunosuppressive properties (Thornley et al. 2014). While the paper focuses on immunological models, one can imagine that this target might be further investigated in the immunotherapy setting.

Seemed to me there was a fair amount of unpublished data in these talks that we can look forward to seeing published sometime soon, no doubt. In the meantime I’d bet some invention disclosures and preliminary patent filings are in the works!

stay tuned…