Patients must choose between their life and their vision.

Choroidal melanoma (CM) is the most common intraocular cancer in adults, with an incidence of approximately 11,000 patients per year in the United States and Europe. CM comprises approximately 90% of all cases of uveal melanoma, consisting of melanomas in the choroid, ciliary body and iris, which are collectively referred to as the uvea. It is estimated that 96% of patients are diagnosed early without clinical evidence of metastatic disease. There are approximately 2,000 new cases of choroidal melanoma treated each year in the United States and 1,600 new cases treated each year in Europe. However, there is a high number of patients with indeterminate lesions that are considered an early-stage diagnosis of melanoma that are not treated immediately given the lack of vision preserving therapies. Despite the current treatments with radiotherapy, the long-term prognosis is poor with death occurring in more than 50% of cases. There are no FDA-approved therapies for choroidal melanoma. We intend to develop belzupacap sarotalocan (bel-sar), our first virus-like drug conjugate (VDC), as a first line therapy to treat early-stage disease, which includes small melanomas and indeterminate lesions representing approximately 9,000 patients in the United States and Europe.

Choroidal melanoma is the most common primary eye cancer in adults

We believe that earlier diagnosis and early treatment intervention of lesions in the eye with a vision preserving therapy before the onset of metastatic disease may dramatically change outcomes for patients.

Bel-sar is injected into the eye where it selectively binds to the cell membrane of choroidal melanoma cells. Once bel-sar is bound to the tumor cell membrane it delivers a potent photosensitizing drug that is then activated with infrared light. As a result of bel-sar’s targeted binding to the tumor cell, upon light activation, bel-sar triggers the generation of singlet oxygen that causes a physical disruption of the cell membrane leading to acute cellular necrosis. This process also activates the patient’s innate and adaptive immune system to further identify and destroy cancer cells with the potential to prevent metastatic disease.


Bel-sar, our first VDC candidate, is a virus-like particle conjugated with a novel light activated cytotoxin being developed for the first-line treatment of early-stage choroidal melanoma. We have completed a Phase 1b/2 trial using intravitreal administration that has demonstrated safety and efficacy based on endpoints in alignment with global Health Authorities. In addition, we are currently conducting a Phase 2 dose finding trial using suprachoroidal (SC) administration. An interim analysis of the safety and efficacy data of this ongoing study has shown that SC has the potential to be an optimal route for the delivery of bel-sar to treat tumors in the choroid. We believe the data from these two studies support further advancement into late-stage clinical development and we have initiated start up activities of a global Phase 3 trial.