targeted therapy | PeggyRCC.com

I was dying ten years ago. My kidney cancer had moved into my lungs, threatening to choke me to death.The tumor and kidney were gone, but 100s of tiny lung metastases were growing. Lucky to get an FDA-approved immune therapy, high dose interleukin 2, my own immune system was revved up so as to destroy the cancer. Thus, I am intrigued by all things about the immune system and cancer research. “Adaptive immunity in cancer immunology and therapeutics”is one of the most comprehensive explanation of the tumor cell/immune system interactions–that I can somewhat(!) understand.

http://ecancer.org/journal/8/full/441-adaptive-immunity-in-cancer-immunology-and-therapeutics.php

My summary is below, a more patient-friendly version. Don’t hesitate to take on the original, via the link! It is just the kind of article to take to your doctor to discuss immune response meds/treatments. It begins with the “abstract”, a summary of the information to follow.

Abstract: The vast genetic alterations characteristic of tumours produce a number of tumour antigens that enable the immune system to differentiate tumour cells from normal cells. Counter to this, tumour cells have developed mechanisms by which to evade host immunity in their constant quest for growth and survival. Tumour-associated antigens (TAAs) are one of the fundamental triggers of the immune response. They are important because they activate, via major histocompatibility complex (MHC), the T cell response, an important line of defense against tumourigenesis. However, the persistence of tumours despite host immunity implies that tumour cells develop immune avoidance. An example of this is the up-regulation of inhibitory immune monoclonal antibodies in clinical practice have been developed to target tumour-specific antigens. More recently there has been research in the down-regulation of immune checkpoint proteins as a way of increasing anti-tumour immunity.”

Immune Responses in Tumors—A Quick Summary by Peg

Since cancer cells are genetically different from normal cells, they also produce different substances—antigens—which can make them more noticeable to the immune system. Any antigen will generate a response from the immune system—think how the body reacts to an infection, an insect sting or a splinter.
Antigens trigger the immune system into action, keeping abnormal cells from taking over the system—most of the time. To grow, tumor cells develop inhibitory responses to limit or down-regulate those immune responses. An over-active immune response can be problem, well-known to those with severe allergies or auto-immune diseases like lupus. Keeping the proper balance is the norm for the immune system, despite ongoing external and internal changes

Using knowledge of these interactions to support the immune system, researchers have develop agent/medications. These are intended to strengthen the beneficial responses, and to prevent the tumors from suppressing or down-regulating those desired responses. Some monoclonal antibodies can effectively target these tumor-specific antigens and trigger tumor death or inhibit such growth. Some of these new agents include bevacizumab (Avastin), rituximab (Rituxin), alemtuzumab (Campath or Lemtrada), bortezomib (Velcade), denosumab (Xgeva) and trastuzumab (Herceptin), among many others, and for a variety of cancers.

Be aware that these agents may be called by the brand name, as Sutent, or the scientific name, as sunitinib, and may have several brand names for different cancers. Just another new challenge to all of us newbies.

Tumors exist with a system of structures, various types of cells and with a chemical signaling process. These shifts away from the normal cells and organs produce tumor antigens. The immune system notices the antigens and works to destroy the foreign cells. Then the tumors shift to counter the immune response in an endless signaling battle. It is a dynamic “fail-safe” system, with multiple checks and balances, work-around pathways, evasive signaling, and constant testing to maintain itself. When this system does fail, a tumor can be established and move to different sites.

Solid tumors have a tumor core, a margin that is invading into a healthy structure–blood vessels or layers of an organ–and lymphoid components. This can vary patient to patient, despite the seeming similarity of tumors, and vary from one metastatic tumor site to another. Inside the tumor will be the immune-cell types–macrophages, dendritic cells, natural killer (NK) cells, mast cells, B cell, and T cells. Different immune cells can be found in different parts of the tumor, and the variation and the density of these cells may play a role in clinical response. It may be that this reflects the robust nature of the natural response to the tumor invasion, or reflect that the system is being overwhelmed by the tumor. Others think that the infiltration of immune cells can be utilized the support of the treatments given to the patient.
The linked journal article goes into detail as to the various types of responses, including adaptive immunity, immune editing and immune evasion. In summary, there are numerous approaches to limit tumor growth within the complex system of antigens and immune responses.
As immune cells infiltrate a tumor, that infiltration can be measured. What is the meaning of a higher or lower level of immune cell infiltration? The following paragraph sums up the challenge of using tumor infiltration as a marker of prognosis or treatment response.
It is a commonly held belief that infiltration of immune cells into tumor tissues and direct physical contact between tumor cells and infiltrated immune cells is associated with physical destruction of the tumor cells. That can reduce the tumor burden, and improve prognosis. An increasing number of studies, however, have suggested that aberrant infiltration of immune cells into tumor or normal tissues may promote tumor progression, invasion, and metastasis. Neither the primary reason for these contradictory observations, nor the mechanism for the reported diverse impact of tumor-infiltrating immune cells has been elucidated, making it difficult to judge the clinical implications of infiltration of immune cells within tumor tissues. J Cancer 2013; 4(1):84-95. doi:10.7150/jca.5482

Tumor Infiltrating Immune Cells—a Good Sign or Not?

If the immune system is at work, immune cells infiltrate the tumor to work directly against the tumor cells, is the tumor destroyed? Does the body naturally destroy the tumor? Does the patient benefit from medical treatments which support the immune system? Unfortunately, the presence of the tumor-infiltrating cells can mean very different things, with a better prognosis in one type of cancer, and a poorer prognosis in another.

Monoclonal antibodies can target antigens in blood cancers and solid tumors. In blood cancers, antibodies counter several cluster of differentiation (CD) markers, and in solid tumors, growth factors such as EGFR (epidermal growth factor receptor) or angiogenesis factors, such as vascular endothelial growth factor (VEGF). The mechanisms of action can lead to direct cell death, or simply impede its growth or inhibit checks on the immune response.

Normal cells are naturally programmed to die, but cancer cells do not “follow the program”. When certain proteins on the surface of cells bind with one another, the expected immune response is inhibited. These anti-PD-1 (anti-Programmed Death-1) proteins bind with other proteins, the binders or ligands, PD-L1 and PD-L2. Studies indicated these agents can help the immune system, with some disease stabilization or tumor shrinkage. Recent trials show some response by 20-25% of patients, some of whom had failed previous treatments. Some responses lasted more than a year. In a few cases, some responses were lasted for a period after stopping the medications. Newer trials will likely combine several of these therapies. This is not without risk, as some had severe side effects, and several patients died from such side effects.

Nevertheless, the earlier successes with this approach and the increased knowledge of the various immune responses to be targeted will continue, especially in combination studies. This work will have impact on existing immune therapies, as does the more integrated approach to cancer treatment.

I welcome any comments and corrections, and remind you that I am a patient, and am not a medical professional. My goal is to help educate other patients to receive the best understanding of their illness and best possible treatment.

Peggy Zuckerman

peggyzuckerman@gmail.com

“Now what?” may be the first coherent question a newly diagnosed cancer patient asks. Maybe the smarter version of that is “What–when and why?” And your doctor had better have a good answer, as to the treatment, the when and the why.

We cancer patients usually get surgery “first”, even when the disease has spread. Primary surgical strike and then a clean-up operation, in the ‘war on cancer’ parlance, we think–when we can think. “But which is the best and first clean-up approach?” we must ask. “What works the best? What can I take with my other health problems? Where does surgery or radiation fit in this scheme? What does the doctor favor and why? Where do I get this treatment? And then what?”

Treatments and their sequence are often chosen with little reliance or clarity as to the data. But some light was shed today at ASCO (American Society of Clinical Oncology). It released a comparison of the sequencing of High Dose Interleukin2 (HD IL2) and of targeted therapies for metastatic RCC. Which should come first?

It shouldn’t be a high-stakes gamble to choose a medication, as no one can guarantee any results–with any of the meds. You take a chance with any drug, so which do you start wi We may be closer to a logical approach in sequencing these drugs. Sequencing of these highly different medications has measurable effect on overall survival (OS)—and to patients’ lives. That sequencing is critical and certainly can extend life, even when treatments fail, as they so often do.

A retrospective study of 97 US patients who received HD IL2, before or after a targeted therapy was just presented at ASCO. These patients were followed for a median duration 37 months–half more than 37 months, half fewer than 37 months. Of that group, 22% had either a partial (14%) or complete (8%) response to HD IL2. (No specifics as to what was a “partial” response, perhaps a 30% shrinkage of the total tumor burden). In addition, another 24% of patients had Stable Disease(SD). Thus, nearly half of these patients benefited from having had HD IL2.

Stable disease is better than progressive disease, as any patient knows, though it was rarely measured in older trials. Though we patients really want a cure, we do want to be around for the next treatment, to have a surgery or ablation to remove the “stable” tumor, or to try another medication.

Of these 97 patients, 82 received HD IL2 before any targeted therapy. Another 15 patients had HD IL2 following a TKI therapy. That timing made an important difference. HD IL2 followed by the TKI, showed a median Overall Survival (OS) of 61.8 months. The OS of those with the TKI before the HD IL2 was 48 months. A median, not an average, so half lived longer, half lived shorter than the quoted medians.

A pre-2006 NCI (National Cancer Institute) series showed a 19 month median survival for HD IL2 alone, and a similar 19 months for the use of targeted therapy alone. Using the two in sequence dramatically improved OS, especially when HD IL2 was first line of treatment. Obviously things have improved, though it can be very difficult to compare older trial data, as so many variables are different–including the type of RCC the patients had as they entered the trials.

Several points can be made from this study. First, no therapy should be examined only as to Complete or Partial Response. Stable Disease also adds to Overall Stability. To stop the tumor from growing, even if for a period of time, is valuable to patients and can prep them for the next anticipated treatment. Sure beats tumor growth!

Second, therapies should be chosen to maximize their impact on the overall survival of the patient. Some patients will naturally be precluded (or delayed) from surgery, or taking one drug due to existing co-morbidities, due to heart disease or liver damage. For those post-op patients, likely to tolerate the side effects of HD IL2, it should be given in a first-line setting.

The most critical variables that impact patients are the recommendations and expectations of the physician. Most patients are not even told about HD IL2 treatment, or it is dismissed casually as “not for you”. Others are told to wait until more mets emerge, with some weird theory that waiting for more trouble is a good thing! Many nephrectomy patients are not monitored post-operatively, despite the risk of mets. This is surely an indicator of the lack of knowledge by urologists. Still others are told that the disease has spread, and that nothing can be done–also untrue.

The rarity of RCC and its variants leaves most physicians unaware of all options in the field, and how to any one might suit for a particular patient. Most oncologists to whom patients are referred, have little or no experience treatmenting for RCC, or may not access to academic centers for support until it is too late. Even the pathology of the primary tumor and later metastases may be questionable, adding to the challenge of care.

With the dramatic changes in the RCC field, this is to be expected—but not tolerated. The patient may have to provide his physician with the data that can extend or save his life, which is a sad but realistic commentary on the field today.

Tag Archives: targeted therapy

Adaptive Immunity in Cancer Immunology & Therapeutics–My Summary

Treatments for Metastatic RCC? Does Timing Matter? Who Is On First?

Recent Posts

Recent Comments