Over the last 50 years, doctors have been working to improve clinical outcomes for patients with a rare but aggressive form of ocular cancer: uveal melanoma. However, there has been little improvement in treatments or patient outcomes. But recently, that looks like it might change. According to Medical XPress, tebentafusp is the first therapeutic shown to improve uveal melanoma survival rates.
Tebentafusp
Developed by Immunocore, tebentafusp is described in an article within Clinical Cancer Research as:
a first-in-class bispecific fusion protein designed to target gp100 (a melanoma-associated antigen) through a high affinity T-cell receptor (TCR) binding domain and an anti-CD3 T-cell engaging domain, which redirects T cells to kill gp100-expressing tumor cells.
In short, intravenously-administered tebentafusp helps the immune system to recognize and attack tumor cells. So far, in the United States, tebentafusp received Breakthrough Therapy designation by the FDA. This designation helps develop and assess treatments for serious, rare, or life-threatening conditions. Altogether, Breakthrough Therapy designation is designed to highlight therapies that might be better or more effective than the current standard-of-care or currently available treatments.
The Research
This most recent research centers around data which suggests tebentafusp could be beneficial in improving survival rates for uveal melanoma. Currently, uveal melanoma has an extremely poor prognosis. If the cancer metastasizes, the one-year survival rate is only around 50%. Thus, it is imperative to develop a better treatment solution.
Within this study, 378 patients enrolled. All patients had metastatic uveal cancer. During the trial, 252 patients (66.6%) received tebentafusp. The remaining 126 patients (33.3%) received either immunotherapy or chemotherapy treatment. Researchers discovered that:
- The 1-year survival rate for those receiving immunotherapy or chemotherapy was 59%. Altogether, those receiving tebentafusp saw significantly higher survival rates (73%).
- Overall, the tebentafusp survival benefit is 49%.
- Tebentafusp reduced the mortality risk by around 50%. This is significant, considering uveal melanoma often metastasizes to the liver, where there is no treatment or standard-of-care therapies.
- While tebentafusp was relatively safe and well-tolerated, some side effects (especially skin-related) occurred. In rare cases, patients experienced an overactive immune system, leading to a cytokine storm.
Moving forward, researchers hope to discover whether tebentafusp can confer protection against recurrent cancer. Thus, they want to see if they can evaluate the therapy in patients whose uveal melanoma is in remission.
Uveal Melanoma
Melanoma is a rare form of cancer which occurs in melanocytes, or melanin-producing cells. Although melanoma usually affects the skin, it can also affect the eyes or metastasize to internal organs. While uveal melanoma, or melanoma affecting the uvea, is relatively rare, it also comprises 3-5% of all melanomas and is the most common eye cancer in adults.
Uveal melanoma impacts the middle layer of the eye: the uvea. This exists between the sclera and retina. In uveal melanoma, tumors form either in the iris, ciliary body, or choroid. However, in most cases of uveal melanoma, the choroid is affected. Uveal melanoma more commonly affects older individuals (65-70+), those with light-colored eyes, and those who are fair-skinned.
Because uveal cancer may not have any symptoms, especially in early stages, eye exams are imperative. When ophthalmologists dilate the pupil, they can find early signs of uveal melanoma. Other symptoms might arise as the cancer progresses. Symptoms include:
- A dark spot on the iris
- Floaters or “flashes” of light
- Pupil size or shape changes
- Cataracts
- A change in how the eye is positioned within the socket
- Blurred vision
