Interferon is a protein the body naturally produces to combat illnesses. It is a type of immunotherapy, which harnesses the body’s immune system to fight cancer. For many years, interferon was a primary therapy used for melanoma after surgery to reduce the risk of the cancer returning. Understanding its function provides insight into the foundations of melanoma immunotherapy.
How Interferon Works Against Melanoma
Interferon’s effectiveness against melanoma stems from directly hindering cancer cells and stimulating a broader immune response. It has an anti-proliferative effect, meaning it can slow the rapid growth and division of melanoma cells. By interfering with the cell cycle, it disrupts their ability to multiply, which helps control the spread of any cancer cells remaining after surgery.
Beyond this direct action, interferon acts as an alert system for the immune system. It boosts the activity of immune cells, including T-cells and natural killer (NK) cells, which are designed to identify and destroy abnormal cells. Interferon makes melanoma cells more recognizable by increasing the expression of molecules on their surface called major histocompatibility complex (MHC) antigens. This enhanced visibility makes it easier for T-cells to eliminate the cancerous cells.
This process also involves attracting other immune cells to the tumor. Interferon prompts cancer cells to release chemical signals that recruit these cancer-killing immune cells, amplifying the body’s defenses. It may also inhibit angiogenesis, the process by which tumors form new blood vessels for nutrients. These combined effects create a hostile environment for remaining melanoma cells, aiming to prevent them from establishing new tumors.
Types of Interferon and Treatment Regimens
The type of interferon historically used for adjuvant melanoma treatment is interferon alfa-2b. This synthetic version of the naturally occurring protein is administered in a structured, high-dose regimen. The treatment protocol is known for being intensive and demanding for patients.
Treatment begins with an “induction phase” that lasts for about a month. During this period, patients receive high doses of interferon alfa-2b intravenously, meaning the drug is delivered directly into the bloodstream. This often requires daily visits to a clinic or hospital, with the goal of quickly activating the immune system to attack residual cancer cells.
Following the induction phase, patients move into a longer “maintenance phase.” This part of the regimen can last for up to a year and involves lower doses of interferon that patients can self-administer at home. These are given as subcutaneous injections, meaning the drug is injected just under the skin.
A modified version, pegylated interferon alfa-2b, was also developed. The “pegylation” process attaches a molecule to the interferon, allowing it to remain in the body longer. This modification means injections are required less frequently, such as once a week, which can be more convenient for patients.
Managing Treatment Side Effects
The side effects of interferon treatment are a significant consideration and require careful management. While experiences vary, some effects are common and can impact a person’s quality of life. Regular medical monitoring is a standard part of therapy due to potential effects on the body’s organs and blood counts.
Common side effects include:
- Severe flu-like symptoms, such as high fever, chills, muscle aches, and headaches, that often occur shortly after the medication is administered.
- Profound fatigue, a debilitating level of exhaustion that can persist throughout treatment and interfere with daily activities.
- Depression and mood changes, which can range from mild irritability to severe depression. It is important for patients to discuss these changes with their oncology team.
- Liver enzyme abnormalities, which are tracked through routine blood tests to ensure the liver is not being damaged.
- A decrease in white blood cells, red blood cells, and platelets, which can increase the risk of infection, anemia, and bleeding.
Current Role in Melanoma Therapy
High-dose interferon was once a standard adjuvant therapy for high-risk melanoma, approved by the U.S. Food and Drug Administration in 1995. For many years, it was one of the few options available to patients after surgery to help prevent the cancer from returning. Its use was based on clinical trials that showed it could delay the recurrence of melanoma.
However, the landscape of melanoma treatment has changed. Interferon is now rarely used as a first-line adjuvant therapy due to its significant toxicity profile. While interferon can delay recurrence, its benefit to overall survival has been debated, and the difficult side effects often lead to patients discontinuing treatment.
The development of immune checkpoint inhibitors and targeted therapies has changed the management of melanoma. These newer classes of drugs have demonstrated superior results in preventing melanoma recurrence and often have more manageable side effect profiles. As a result, they have largely replaced interferon as the standard of care for adjuvant therapy in patients with high-risk melanoma.
Today, the use of interferon is limited to specific clinical situations. It might be considered for patients who are not candidates for newer therapies or in regions where those advanced treatments are not available. Its historical significance lies in being one of the first immunotherapies to show a benefit in melanoma, paving the way for the more effective treatments used today.