FAQs about Antibody Therapy

Herceptin 

Should I receive Herceptin^® (trastuzumab) with my chemotherapy?

That depends on whether you are HER2-positive or not. HER2 is a protein overexpressed on tumor cells in 20 percent to 25 percent of breast cancer patients. This protein is overexpressed, usually when the gene for its expression is amplified. If that is the case, you are a candidate for trastuzumab and you should receive it with your chemotherapy.

A large randomized trial in women with advanced breast cancer (cancer already spread to other organs beyond the breast, such as liver, lung, bone, etc.) showed that the addition of trastuzumab to chemotherapy prolonged their survival. Recently, four large randomized trials in women with early-stage breast cancer have shown that use of trastuzumab in addition to chemotherapy cuts the risk of cancer coming back by half.

This is a very well-tolerated antibody with minimal side effects, except for an approximately 4 percent risk of congestive heart failure, and should now be considered the standard treatment in women with HER2-positive breast cancer. The benefits for lymph node-positive disease are clear, but the threshold for use in node-negative disease should be discussed with your doctor. 

I finished adjuvant chemotherapy 8 months ago for early-stage breast cancer and was just told by my doctor about Herceptin^® (trastuzumab). Should I take it? 

When the results of the trastuzumab trials were announced, the patients who had been randomized on those trials to not receive trastuzumab were given the option to receive it if they had finished their chemotherapy up to 6 months ago. At some institutions, physicians went back up to 12 months and gave women that option. Since you are within that 6 to 12 month window, it is reasonable for you to consider it after knowing the side effects and understanding the risks, cost, and inconvenience issues. You should keep in mind that the advantage rendered by trastuzumab in the adjuvant setting is significant. A large international clinical trial is ongoing to determine the benefit of adding Tykerb^® (lapatanib) to patients with HER2-positive breast cancer who did not receive adjuvant trastuzamab.

I am afraid of the heart damage associated with Herceptin^® (trastuzumab) therapy and want to know if there are any ways to avoid it?

The most important way to avoid this is to not receive trastuzumab together with other drugs with potential of heart disease, such as Adriamycin^® (doxorubicin). There may also be some advantage to not receiving it in close proximity with doxorubicin. Beyond that, it is important to realize that such cardiac damage is uncommon and significant congestive heart failure is seen in only approximately 4 percent of patients in large clinical trials (aggregate number of patients from four clinical trials is about 14,000).

There are ways to monitor cardiac toxicity by assessing your heart function  periodically while you receive treatment. It is also important to know that in many cases such damage is reversible. It tends to occur early rather than late unlike the heart damage with doxorubicin, which is cumulative and occurs after a certain total dose threshold is crossed. 

Is the heart damage with Herceptin^® (trastuzumab) permanent?There is evidence that in most cases the heart damage of trastuzumab tends to be manageable, even temporary, and reversible in some cases. In fact, many patients have been re-challenged with trastuzumab after initial evidence of heart damage and have been able to tolerate it. However, this issue should not be taken lightly, and you should be on regular cardiac monitoring. If you have a pre-existing heart condition or borderline poor heart function, you may or may not be a candidate for trastuzumab. You should discuss this with your doctor. How common is heart damage with Herceptin^® (trastuzumab)?

In the initial study of trastuzumab in patient with metastatic breast cancer, serious cardiac damage with congestive heart failure was seen in 19 percent of patients who received it concurrently with Adriamycin^® (doxorubicin) and cyclophosphamide. However, when used by itself or with drugs such as Taxol^® (paclitaxel), cardiac damage is under 4 percent. In many cases, this damage is reversible. Some of these patients can even be re-challenged with trastuzumab to complete their intended prescribed therapy.
 
How long will I take Herceptin^® (trastuzumab) after adjuvant chemotherapy for early-stage breast cancer?

You should be receiving it for a total of 1 year because the only trial comparing 2 years of trastuzumab to 1 year of trastuzumab has not been reported. There is only one small study from Finland indicating that a much shorter duration of trastuzumab (about 9 weeks or so) in addition to chemotherapy may confer the same magnitude of benefit as seen with 1 full year of trastuzumab, but that data is not considered strong enough evidence to outweigh the data from four large randomized trials.
 
Do I have to go every week for my Herceptin^® (trastuzumab)? 

You have the option of going every 3 weeks as trastuzumab stays in circulation for at least that long. It has been shown in clinical trials that the blood levels of trastuzumab are about the same if you receive three times the weekly dose every 3 weeks.
 
What if I am allergic to Herceptin^® (trastuzumab)? 

True allergy to trastuzumab is rare. The majority of patients who start trastuzumab have no symptoms. Occasionally they may feel shaking chills, even low-grade fevers at the time of first infusion because it is a foreign protein being injected into your body. Subsequent infusions generally do not have that side effect.
 
What is the best chemotherapy with Herceptin^® (trastuzumab)?

There is no single chemotherapy that is considered "the best." Laboratory studies have indicated that trastuzumab improves the effects of certain chemotherapy drugs. Only your physician can decide the best treatment with trastuzumab, which also depends on whether you are receiving it in the early postoperative setting or in advanced breast cancer, where cancer has already spread to other organs.

Avastin 

Can I receive Avastin (bevacizumab) with my dose-dense adjuvant chemotherapy? 

There is a pilot study ongoing in the United States to assess the feasibility of this approach. Until then, bevacizumab should not be routinely used in the adjuvant setting or with dose-dense therapy outside of a clinical trial.
 
Is it safe to receive Avastin^® (bevacizumab) with my chemotherapy with TAC?

The data on bevacizumab that was reported from a large randomized trial recently was with single-agent Taxol^® (paclitaxel). It has also been tested with Taxotere^® (docetaxel) in small studies that are in various stages of being reported. There is no large experience yet with TAC, and it is premature to comment.