Tag: Immunotherapy

Marking their Territory: Using Cell Markers to Find Cancer and Stop its Spread

Cancer Cell Markers and AntibodyA key way to detect cancer cells in the body is to find “markers” on the cancer cells that don’t exist in healthy cells. For prostate cancer, we use a marker called the prostate specific membrane antigen (PSMA). PSMA is a protein on the cell surface of most prostate cancer cells, but it is not usually present elsewhere in the body. As a result, we’re able to use PSMA in order to track the presence of prostate cancer tumor growth and metastasis. At AACR 2016, the Weill Cornell Medicine (WCM) and Meyer Cancer Center investigators presented the results of two new studies that further hone in on the role PSMA plays in prostate cancer.

While we’ve known about the presence of PSMA for many years, we have recently discovered more about its biology and the tight relationship it has with the key driver of most prostate tumors, the androgen receptor (AR) pathway. As the AR pathway becomes more abnormal (is more dysregulated), the amount or expression of PSMA increases. This means that more aggressive tumors will have more PSMA on the cells.

How do we measure or quantify the amount of PSMA?

At the Weill Cornell Genitourinary (GU) Oncology Program, one way we do this is by using non-invasive methods to locate active tumors in prostate cancer patients. By tagging an antibody or small molecule with a particle that gives off energy, we can “see” the PSMA using imaging techniques. In this case, we can give people an injection to bring these tagged molecules into the body and then follow the “energy” the molecules are giving off with a scan that visualizes the tumors. In some cases, this approach helps us locate tumors that might otherwise be hidden.

However, we may also be able to assess the biology of tumors without a biopsy (non-invasively). To do this, we analyzed men who had undergone molecular PSMA imaging. Following infusion of the anti-PSMA monoclonal antibody J591 which was tagged with a particle, men underwent scanning. Based upon a system we previously published, we scored how bright their tumors were with the belief that brighter tumors would be more aggressive. In long-term follow up of the men who underwent imaging between 2000-2015, our hypothesis was confirmed. The men with the brighter tumors had higher rates of mortality, even among those who received the newer, better therapies. This type of non-invasive molecular imaging may assist physicians in determining prognosis, which may in turn guide therapy choices for especially aggressive cancers.

Antibodies as a Treatment Vehicle

In addition to tagging an antibody with an imaging agent, we can label J591 with a radioactive particle capable of killing the cancer cells, termed radioimmunotherapy. For more than a decade, we have delivered different versions of this therapy to patients at WCM. A phase II clinical trial published in 2013 was shown to be very successful at delivering a large, single-dose of radioimmunotherapy to patients, also showing that those patients receiving a larger dose had better response and survival (a “dose-response”). Building on the results of this trial, we hypothesized that by splitting the radiation dose and giving half initially and half two weeks later (this is called “dose fractionation”) that we would be able to ultimately deliver a higher dose of the treatment. At ASCO in 2010, we demonstrated this to be a promising approach to treatment and will be presenting a follow up expanded version of this study in June at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.

At AACR 2016, Dr. Ana Molina presented results of a pilot study of hyperfrationated (very split doses) 177Lu-J591, which delivers the radioactive particle lutetium-177 (177Lu) to tumors via the anti-PSMA monoclonal antibody J591. In this study, small doses of the radioimmunotherapy were delivered every two weeks until blood counts started to drop, as measured by the level of white blood cells and platelets. This treatment approach allowed all patients in this small study to receive a higher total dose than could be safely delivered with a large single dose. Two patients received five and six total doses of the treatment, reflecting a range 179 – 214% higher than the single large dose. As a result, this new approach to administering this type of immunotherapy with very split dosing may have long-term merit for men with advanced prostate cancers.

Today, men with advanced prostate cancer are able to benefit from a number of new treatment options, including the common oral hormonal drugs, abiraterone and enzalutamide. These hormonal drugs help decrease the burden of the cancer, maintain or improve the quality of life, and allow men to live longer. However, none of these drugs are curative, so we still need to make advancements in the field.

This is why we continue to use what we already know about cancer “markers,” such as PSMA, and to build on this knowledge in order to better diagnose and treat prostate cancers in a way that exploits these markers and keeps the cancer at bay. We are also constantly seeking new ways to better “see” and leverage these markers, and specifically PSMA, to prevent the growth and spread of prostate cancer.

Learn more about some of our current open clinical trials exploring this approach:

What are Cancer Neoantigens? The Link Between Neoantigens and Immunotherapy

By Bishoy Faltas, M.D.

Our immune system has evolved over time to enable us to fight infections. Our bodies need to differentiate between our own cells (self) and cells from bacteria and viruses (non-self) in order to mount an effective attack to eliminate the invaders. In order to do that, our immune system has learned to recognize fragments of foreign proteins, which carry a specific sequence that marks them as “targets” for the immune system. We call these antigens.

Cancer cells thrive because they hide from the immune system, but their disguise is not perfect. Cells typically become cancerous because of changes in their genetic makeup. These same changes can result in proteins that the immune system is able to recognize as foreign. These are called neoantigens, and refer to new cancer antigens that cue the immune system to attack the cancer and eliminate it.

neoantigen[2]
New sequencing technologies enable us to detect new cancer antigens unique to each patient.
The immune system just needs a little help to make this happen. To tip the balance in favor of the immune system, we now use drugs called immune checkpoint inhibitors. These unleash the power of the immune system to attack the tumor. A good way to think about it is as “releasing the brakes” off the immune response. This approach to treatment is very promising for bladder cancer, especially when other treatments have failed to stop the cancer from progressing or metastasizing to other organs.

To understand which patients are most likely to respond to these immune checkpoint inhibitors, we conducted a study examining the neoantigens in bladder cancer patients at Weill Cornell Medicine. Our analyses found many differences in the neoantigens between untreated tumors and advanced tumors that had previously been treated with chemotherapy from advanced chemotherapy-resistant bladder cancers. More details on our findings can be found here:

In the future, we are hoping to use neoantigens as biomarkers that tell us which patients are most likely to respond to specific immunotherapies. A form of precision medicine, this will help us to narrowly tailor our treatment approach to each patient.

Some of our current immunotherapy treatments for people with bladder cancers include:

Cancer: A Wolf in Sheep’s Clothing

Immunotherapy wolf in disguiseCancer cells can be pretty sneaky, altering their make-up or microenvironment to avoid detection by our body’s immune system. As a result, the immune system, which is designed to fight off “invaders,” can’t detect cancer as foreign and doesn’t have its guard up.

Earlier this month, NewYork-Presbyterian Hospital kicked off a new ad campaign highlighting how immunotherapy is working to change just that. Immunotherapy treatments are designed to help activate the immune system and kick it into high gear, helping it fight the very cancer it was previously unable to detect.

https://www.youtube.com/watch?v=NmtGKer20aY

New scientific discoveries happening right here at Weill Cornell Medicine are making this possible. Our physician-scientists and researchers at the Meyer Cancer Center have found ways to help the immune system better recognize and destroy cancer cells by designing new immunotherapy drugs, cancer “vaccines,” and combination treatments. Through precision medicine and an individualized approach to cancer care, we are developing new ways to treat cancer more successfully than ever before. And, we’re accomplishing these results with less toxicity.

Over the past decade, the U.S. Food and Drug Administration (FDA) has approved several new immunotherapy drugs for advanced cancers. At the Weill Cornell Genitourinary (GU) Oncology Program, we have greatly contributed to the efforts to obtain FDA-approval for immunotherapies for GU cancers, including kidney cancer, bladder cancer, and prostate cancer.

For kidney cancer, we have been involved in many studies of drugs utilizing the immune system to fight cancer, including the phase 2 clinical trial that formed the basis for the large trial leading to the FDA approval and general availability of nivolumab (Opdivo) for renal cell carcinoma. Nivolumab is an immunotherapy that works by allowing the body’s existing immune system to kill tumors. Our team is now working on ways to improve this drug and other types of drugs.

For bladder and other urothelial cancers, we have been instrumental in the development of several antibodies that can be used with and without chemotherapy. Sacituzumab Govitecan (IMMU-132), an antibody-drug conjugate, has had remarkable preliminary activity. It works by leveraging the immune system and bringing a powerful drug directly to the interior of cancer cells in order to kill them from the inside out. We are continuing to use this drug as well as other immunotherapeutic agents to improve outcomes for patients with these types of cancer.

Based upon several scientific properties, prostate cancer is a good tumor type for immunotherapy, and in fact, the first therapeutic cancer vaccine (used to treat cancer rather than prevent cancer) was approved for prostate cancer. At Weill Cornell Medicine, exploiting the immune system remains a focus in fighting prostate cancer, with a number of ongoing and upcoming clinical trials. Weill Cornell Medicine continues to be a worldwide leader in work with monoclonal antibodies, which are proteins (like a “key”) that very specifically target cancer cells (with a specific “lock” that is not present on normal cells). In particular, our work with antibodies against prostate-specific membrane antigen (PSMA) has led to the development of several targeted therapies for prostate cancer. These antibodies can be linked to powerful radioactive particles or drugs that seek out prostate cancer cells (like a smart bomb). For men with prostate cancer whose PSAs rise despite hormonal therapy, we are leading a study of targeted radioimmunotherapy that aims to prevent metastatic disease. In addition, the antibody itself may be able to generate an immune response in prostate tumors and lead to clearance of circulating tumor cells. We are also working on developing vaccines for men with rising PSAs following surgery or radiation.

We continue to examine many promising, cutting-edge immunotherapies through our robust clinical trial program. Click the below links to learn more about eligibility and open clinical trials across the spectrum of GU cancers:

Open Immunotherapy-Based Clinical Trials

Prostate Cancer

Kidney, Bladder and Urothelial Cancers

To search our complete list of our open clinical trials, click here.