Immune Checkpoint Inhibitors in Melanoma: New Directions


The drugs pembrolizumab (Keytruda) and nivolumab (Opdivo) were approved by the U.S. Food and Drug Administration (FDA) in 2014 and 2015, respectively. These two competing blockbuster drugs are already changing the outlook in metastatic melanoma, previously considered to be a fatal disease. Known as ‘immune checkpoint inhibitors,’ they work by releasing ‘brakes’ on a patient’s own immune system, freeing it to attack tumors. In the wake of their success, researchers are now taking immune checkpoint inhibition in new directions. Continue reading…


OX40 is a Potent Immune Stimulating Target in Late Stage Cancer Patients

“OX40 is a potent co-stimulatory receptor that can potentiate T cell receptor signaling on the surface of T lymphocytes, leading to their activation by a specifically recognized antigen. In particular, OX40 engagement by ligands present on dendritic cells dramatically increases the proliferation, effector function and survival of T cells. Preclinical studies have shown that OX40 agonists increase anti-tumor immunity and improve tumor-free survival. In this study, we performed a Phase I clinical trial using a mouse monoclonal antibody (mAb) that agonizes human OX40 signaling in patients with advanced cancer. Patients treated with one course of the anti-OX40 mAb showed an acceptable toxicity profile and regression of at least one metastatic lesion in 12/30 patients. Mechanistically, this treatment increased T and B cell responses to reporter antigen immunizations, led to preferential upregulation of OX40 on CD4+ FoxP3+ regulatory T cells in tumor-infiltrating lymphocytes andincreased the anti-tumor reactivity of T and B cells in patients with melanoma. Our findings clinically validate OX40 as a potent immune-stimulating target for treatment in cancer patients, providing a generalizable tool to favorably influence the antitumor properties of circulating T cells, B cells and intratumoral regulatory T cells.”


Depleting Tumor-Specific Tregs at a Single Site Eradicates Disseminated Tumors

“Activation of TLR9 by direct injection of unmethylated CpG nucleotides into a tumor can induce a therapeutic immune response; however, Tregs eventually inhibit the antitumor immune response and thereby limit the power of cancer immunotherapies. In tumor-bearing mice, we found that Tregs within the tumor preferentially express the cell surface markers CTLA-4 and OX40.”


Depleting Tumor-Specific Tregs at a Single Site Eradicates Disseminated Tumors

“Activation of TLR9 by direct injection of unmethylated CpG nucleotides into a tumor can induce a therapeutic immune response; however, Tregs eventually inhibit the antitumor immune response and thereby limit the power of cancer immunotherapies. In tumor-bearing mice, we found that Tregs within the tumor preferentially express the cell surface markers CTLA-4 and OX40.”


Depleting Tumor-Specific Tregs at a Single Site Eradicates Disseminated Tumors

“Activation of TLR9 by direct injection of unmethylated CpG nucleotides into a tumor can induce a therapeutic immune response; however, Tregs eventually inhibit the antitumor immune response and thereby limit the power of cancer immunotherapies. In tumor-bearing mice, we found that Tregs within the tumor preferentially express the cell surface markers CTLA-4 and OX40.”