Medicine  

Scientists are developing a therapeutic vaccine that educates the patient’s immune system to identify and destroy cancer cells. It works like a vaccine via activation of the immune system. However unlike preventative vaccines which are given to healthy people to stop those getting sick, it is given to sick people to make them well; so it works like a drug.

Researchers have taken a truly innovative approach toward treating cancer in their attempt to use the body’s own immune system to fight off the disease. Thus far clinical trials for a cancer vaccine, called ImMucin, have produced promising results.

According to Vaxil BioTherapeurtics, ImMucin's makers, the cancer vaccine triggers an immune response in about 90 percent of all types of cancer.

"We are trying to harness the natural power of the immune system to fight against cancer by seeking out cancer cells and destroying them."

Cancer cells are abnormal cells that have begun to multiply rapidly in the body. Unlike viruses and bacteria, they are not invading bodies, and the immune system finds it difficult to respond. Moreover, the cancer treatments often compromise the immune system, making it even more difficult for it to respond to the cancer.

ImMucin would teach the immune system to send T cells to search for specific markers, which appear on cancer cells, and to destroy only those cells with the cancer marker. The researchers claim that the vaccine can also prevent the cancer from mutating and becoming resistant, a problem found in many other cancer treatment approaches.

The vaccine teaches the immune system to search and destroy cells that have the cancer marker MUC1, and according to Vaxil, 90 percent of all cancers use this specific marker.  These include, lung cancer, prostate cancer, breast cancer, colon cancer, rectal cancer, stomach cancer, pancreatic cancer, leukemia, lymphoma and more.

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“Vaxil is developing a drug to keep the cancer from coming back,” Julian Levy, Vaxil’s CFO, told NoCamels.com. “We are trying to harness the natural power of the immune system to fight against cancer by seeking out cancer cells and destroying them.”

 Levy is confident that ImMucin will be on the market by the end of this decade.

Although ImMucin would not be a “cure” for cancer, when used in addition to treatments such as radiation and chemotherapy, the vaccine would help patients in the earliest stages of cancer significantly increase their chances of survival.

The vaccine has performed consistently well in trials in patients with multiple myeloma and breast cancer, but it’s suspected that at this point Vaxil does not have the resources to further push the drug to the U.S. market. In American trials, drug development and research can cost millions per trial and No Camel reported that Vaxil’s most recent value was only $3 million.

Unlike the Gardasil vaccine commonly given to women to prevent cervical cancer, ImMucin is given to individuals who are already sick. ImMucin is a therapeutic vaccine and works by stimulating the immune system and teaching it to attack cells that possess the markers for cancer.

Recently a Phase I/II clinical trial (VAXIL-001) with, ImMucin, in 15 patients with Multiple Myeloma (a cancer of the blood), has met all endpoints with considerable success.

Another key benefit to the vaccine is the fact that it can be used on nearly all of the world’s population. However, although theoretically it can be used on everyone, the developers warn that since the vaccine uses the body’s immune system to fight off cancer, it would be most effective on individuals with healthy immune systems. This means that unfortunately the cancer would most probably only be effective in cancer patients in the earliest stages of the disease.




SOURCE  No Camels

By 33rd Square

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 Medicine  

Scientists have found a way to target elusive cells that suppress immune response, depleting them with peptides that spare other important cells and shrink tumors in preclinical experiments.

Scientists have found a way to target elusive cells that suppress immune response, depleting them with peptides that spare other important cells and shrink tumors in preclinical experiments, according to a paper published online by Nature Medicine.

“We’ve known about these cells blocking immune response for a decade, but haven’t been able to shut them down for lack of an identified target,” said the paper’s senior author, Larry Kwak, M.D., Ph.D., chair of Lymphoma/Myeloma and director of the Center for Cancer Immunology Research at The University of Texas MD Anderson Cancer Center.

The cells, called myeloid-derived suppressor cells (MDSCs), are found abundantly in the microenvironment around tumors.  Created with other blood cells in the bone marrow, they interfere with activation and proliferation of T cells, the immune system’s attack cells. MDSCs have been shown in mouse models to accelerate cancer progression and metastasis.

“This is the first demonstration of a molecule on these cells that allows us to make an antibody, in this case a peptide, to bind to them and get rid of them,” Kwak said. “It’s a brand new immunotherapy target.”

Kwak has developed anti-cancer therapeutic vaccines to spark an immune system attack against tumors, but their effectiveness has been hindered by factors such as MDSCs that stifle immune response. “The key to taking cancer vaccines to another level is combining them with immunotherapies that target the tumor microenvironment,” Kwak said.

"The key to taking cancer vaccines to another level is combining them with immunotherapies that target the tumor microenvironment."

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Peptide antibodies developed by Kwak and  co-discoverer, Hong Qin, Ph.D., assistant professor of Lymphoma/Myeloma, wipe out MDSCs in the blood, spleen and tumor cells of mice without binding to other white blood cells or dendritic cells involved in immune response.

“That’s really exciting because it’s so specific for MDSCs that we would expect few, if any, side effects,” Kwak said. The team is working to develop the same target for use in humans.

With no candidate targets, the team took an objective approach by applying a peptide phage library to MDSCs, which permitted mass screening for candidate peptides – short sequences of amino acids -- that bind to the surface of the MDSCs.

Peptide phage gathered from the MDSCs were expanded, enriched and then sequenced to identify predominant peptides. The team found two, labeled G3 and H6, that bound only to MDSCs; other candidates were eliminated because they also tied in to other types of cell.

They fused the two peptides to a portion of mouse immune globulin to generate experimental “peptibodies.”  Both peptibodies bound to both types of MDSC – monocytic white blood cells, which engulf large foreign bodies or cell debris, and granulocytic white cells loaded with tiny granules.

The researchers treated mice with two types of thymus tumor with each peptibody, a control peptibody and an antibody against Gr-1. The G3 and H6 peptibodies depleted both types of MDSC in the blood and spleens of mice in both tumor models, while the Gr-1 antibody only worked against granulocytic MDSC.

Both peptibodies also wiped out the MDSCs in both types of thymic tumor and in the blood and spleen of mice with lymphoma.

Analysis of surface proteins on the MDSCs identified S100A9 and S100A8 as the likely binding targets for the two peptibodies.  They’re members of the S100 family of proteins, called alarmins, which are released outside the cell as a danger signal in response to inflammation.

A new class of drugs called immune checkpoint inhibitors block molecules on T cells that shut down immune response, freeing the immune system to attack tumors.  The first of these drugs, ipilimumab (Yervoy®) was approved by federal regulators to treat advanced melanoma. It’s the only drug ever to lengthen survival for those patients. Additional immune checkpoint inhibitors are under development.

“Immune checkpoint blockade is great,” Kwak said.  “There have been dramatic response rates, but those drugs also have side effects. Targeting MDSCs could provide an additional way to unleash the immune system.”



SOURCE  MD Anderson Cancer Center

By 33rd Square

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