It’s Day 7 of our 12 day Countdown to AACR 2016 in New Orleans. After exploring GITR and OX40, we’re now looking at another stimulatory target for cancer immunotherapy: CD40.
We’ve been writing about CD40 as a cancer immunotherapy target for some time. See posts: “CD40 as a Cancer Immunotherapy Target” and “Targeting CD40 in Cancer Immunotherapy.”
Anti-CD40 antibodies are agonists that act on stimulatory signalling receptors on T cells and antigen presenting cells (APCs). Targeting CD40 effectively acts to “put the foot on the gas” and may help generate a better immune response. This could be important in cancers that have fewer natural T cells present.
CD40 is an attractive target because it’s expressed in more than 50% of carcinomas and melanomas and almost all hematological B cell malignancies. Of particular interest is the potential to combine a CD40 agonist with a PD-1/PD-L1 checkpoint inhibitor.
Multiple companies have CD40 agonists in clinical development including Roche, Apexigen, Alligator Biosciences and Seattle Genetics. There are others coming too.
In this preview of AACR 2016, we’re looking at the CD40 landscape. New products and companies have entered the scene, so we’re highlighting them and some of the CD40 presentations to look out for at AACR 2016 (and why they matter).
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At the recent 2014 annual meeting of the Society for Immunotherapy of Cancer (SITC), it was surprising to see how many people stayed till the bitter end of the conference to attend the Hot Topic Symposium on Accelerating Tumor Immunity with Agonist Antibodies.
Readers are well aware of the potential of cancer immunotherapies that block immune checkpoint receptors. After all, the FDA has already approved antibodies that block CTLA–4 (ipiliimumab) and PD–1 (pembrolizumab) in metastatic melanoma, with nivolumab (Opdivo) currently being reviewed for advanced melanoma and lung cancers.
These antagonists, and others in development targeting the PD-L1 signalling pathway, such as MEDI4736 and MPDL3280A, act to reduce the engagement of inhibitory receptors on the T-cell. This results in a releasing of a brake on the T cell response, enabling killer T cells to attack the tumour(s).
CD40 in cancer Source: Costello et al., 1999
However, in order to stimulate an immune response, particularly in tumors with few natural T cells, it is likely that agonist antibodies will be required that act on stimulatory signalling receptors on T cells and antigen presenting cells (APC’s).
In a previous post from SITC, we discussed the potential of agonists targeting OX40, and the rational for combining an anti-OX40 antibody with an anti-PDL1. This is one of the hottest targets that thought leaders are excited about from our discussions.
It isn’t the only one of interest though. Another potential stimulatory target that might be suitable for combination with anti-PD–1/PD-L1 is an antibody against CD40 (not to be confused with OX40). The pathway (shown right) is quite complex.
Subscribers can login to read more about another fascinating talk from SITC 2014 on where the cancer immunotherapy may be heading.