Doxorubicin

Doxorubicin is a chemotherapy drug that has been in use for treating several different types of cancers since the 1970s. It is sold under various brand names and as a generic and is manufactured and distributed by multiple pharmaceutical companies. Doxorubicin is approved by the U.S. Food and Drug Administration (FDA) to treat several types of cancers, but these do not include mesothelioma.

Although not officially approved for any type of mesothelioma, doctors often prescribe doxorubicin for these patients, particularly in combination with other drugs and treatments. Trials and studies have been done and are currently underway to find out how effective this drug can be in treating mesothelioma patients, although there are also risks and side effects, some very serious. When combined with other drugs, in spite of the risks, doxorubicin may prove to be very effective in treating mesothelioma.

What is Doxorubicin?

Doxorubicin is the generic name of a drug that is used to treat several types of cancers through intravenous injection. It is often used as a chemotherapy combination drug, administered along with others for greater efficacy in slowing or stopping the growth of cancer cells. It is sold as a solution to be injected or as a powder that can be made into the solution. Some of the brand names of Doxorubicin are Adriamycin, Rubex, and Doxil and it is currently manufactured by Teva Pharmaceuticals, Janssen Pharmaceuticals, Pfizer, Bedford Laboratories, and other companies.

The first FDA approval for doxorubicin came in 1974 and was awarded to Pharmacia and Upjohn. Over the years since, the FDA has given additional approvals for changes in dosing, generic forms of the drug made by various pharmaceutical companies, and for new uses for which the drug has been proven to be effective and relatively safe.

How it Works

Doxorubicin is an anthracycline, a type of antibiotic. This class of chemotherapeutic agents is made up of drugs derived from Streptomyces bacteria. Although they are antibiotics, they were found to be useful in treating cancers because anthracyclines damage DNA, resulting in cell death. As with many types of chemotherapy drugs, this effect is not limited to cancer cells, so healthy cells in the body can be destroyed, and this causes certain side effects.

Uses for Doxorubicin

The FDA approval for doxorubicin includes specific types of cancer that it has been proven to treat effectively with some risks. Doctors may prescribe the drug for unapproved uses, and this often includes for the treatment of mesothelioma. FDA approval includes treating ovarian cancer after treatment with a platinum-based drug has failed. It can also be used to treat multiple myeloma in combination with the drug bortezomib, and it is approved to treat Kaposi’s sarcoma related to AIDS, after other chemotherapy combinations have failed to be effective. It is not approved for treating any type of mesothelioma, but it is often used for these patients, especially in studies and clinical trials.

Side Effects

Because doxorubicin is not selective only for cancer cells, this drug can cause some side effects related to the damage of healthy cells. These are some of the most common side effects and are typically seen with all kinds of chemotherapy drugs. They include fatigue, hair loss, dizziness, eye pain, discolored urine, increased thirst, weight loss and loss of appetite, nausea, vomiting, fever, diarrhea, constipation, skin rash, mouth sores, anemia, and a weakened immune system that can lead to infections.

Doxorubicin may also cause something called hand and foot syndrome. These are skin reactions on the palms of the hands and the soles of the feet, and are most common a few weeks after starting chemotherapy. The symptoms include stinging in the hands or feet, cracked, dry, and peeling skin, thickened skin, like a callous, redness, blistering, and swelling. Hand and foot syndrome can be very painful and restricts movement and the use of the hands. Patients who experience it should report it to their doctor and consult with a dermatologist.

Black Box Warning and Serious Risks

In addition to the more common and less serious potential side effects of doxorubicin, this drug may cause severe reactions. The FDA includes a black box warning—the most serious warning the FDA offers—for these. They include the possibility that the drug may leak into surrounding tissues at the injection site and cause serious damage with pain, itching, blisters, and sores. This can be painful but also very damaging.

Doxorubicin may also cause life-threatening heart issues, even years after the conclusion of treatment. This includes congestive heart failure and the risk increases with the dose of the medicine. It may also make patients susceptible to serious infections by suppressing the production of blood cells, including the immune system’s white blood cells, in the bone marrow. Doxorubicin may also damage the liver and make a patient more susceptible to developing leukemia. Doctors must be careful to monitor patients before, during, and after treatment for these serious problems. Some patients may not be eligible for treatment with doxorubicin because of existing heart, liver, or immune system impairments.

Studies of Doxorubicin to Treat Mesothelioma

Doxorubicin has not been approved by the FDA to treat mesothelioma, but this is largely because there are relatively few patients with this type of cancer. Doctors and researchers have been trying doxorubicin with mesothelioma patients for years and there are several studies that indicate it may be a promising course of treatment.

Sometimes the studies are very small, including a case study of just one patient published in 2012. A man with pleural mesothelioma was given a combination of chemotherapy drugs that included a form of doxorubicin called pegylated liposomal doxorubicin hydrochloride. This form is thought to be better absorbed by tumors and less by healthy tissues. The man was given this drug in combination with etoposide and paclitaxel. He responded well and in 2012 was still alive nine years after treatment, a major accomplishment for mesothelioma.

In another study, 67 patients with peritoneal mesothelioma were given doxorubicin along with paclitaxel and cisplatin. The results were astounding, with a median survival time of more than six years. One patient in the study survived 12 years. A smaller study confirmed these results by combining cisplatin with various other chemotherapy drugs. The best results were seen with cisplatin combined with doxorubicin.

Mesothelioma is a difficult cancer to treat, and although it isn’t approved to treat this cancer, doxorubicin is proving to have great potential for these patients. Studies and clinical trials are ongoing and some patients are seeing better results than they could have hoped. The problem is that doxorubicin has the potential to cause some serious side effects like heart damage and infections. For patients with mesothelioma, these risks are often outweighed by the benefits.