IL-2 to the rescue?

The authors evaluated the safety and efficacy of administering interleukin-2 directly into in-transit lesions in melanoma patients.

In-transit melanoma is defined as melanoma deposits within the lymphatic vessels more than 2cm from the site of the primary melanoma. If in-transit disease is left unchecked, these patients may experience severe and continuing morbidity (disease conditions) including pain, odor and bleeding as these tumors grow.

Interleukin-2 (IL-2) is a protein that can make the immune system more or less active. Drugs based on IL-2 boost the body’s immune system to help it fight cancer. When administered intravenously (into the veins), very high doses of IL-2 are required to elicit a response, leading to toxicity. This analysis evaluated the safety and effectiveness of administering intra-lesion (straight into the lesion) IL-2.

This evaluation included 6 studies of intra-lesion IL-2.

Response rates by lesion were reported in 5 of the studies. In total, 2,182 in-transit lesions dispersed over 131 patients were treated and evaluated. The average complete response rate (complete disappearance of all signs of cancer) was 78%. The average partial response rate (some disappearance of signs or tumor shrinkage) was 2.5%. The no response/disease progression rate was 19.6%.

Response rates by subject were reported in 4 of the studies, encompassing 410 subjects. Complete resolution of all treated lesions occurred in 49.6% of patients.

Side effects were evaluated in all 6 studies. Pain and localized swelling associated with injection was cited as the most common side effect, affecting nearly all patients. The discomfort tended to be mild, short lasting and easily managed. Also common was associated fever and flu-like symptoms including chills, night sweats, malaise and fatigue. Mild nausea and vomiting were reported in some studies.

The authors concluded that the effectiveness of IL-2, coupled with the minimal associated side effects, demonstrates the potential for this treatment to become the first-line therapy for in-transit disease.