EWSR1 Immunotherapy for Ewing Sarcoma and DSRCT

This trial tests a new immunotherapy treatment, EWSR1 immunotherapy, designed to help the immune system better recognize and fight high-risk Ewing sarcoma and desmoplastic small round cell tumor (DSRCT). The treatment targets a specific genetic change in cancer cells, potentially allowing the immune system to attack the cancer without harming healthy cells. Participants may receive the treatment alone or combined with other medications to assess its safety and effectiveness. This trial could suit individuals with Ewing sarcoma or DSRCT who have completed certain standard cancer treatments and experienced disease progression or recurrence. As a Phase 1 trial, this research focuses on understanding how the treatment works in people, offering participants the opportunity to be among the first to receive this new therapy.

The trial requires a 2-week period without chemotherapy before starting the study treatment. Participants on inhaled corticosteroids or maintenance doses of hydrocortisone are allowed, but concurrent chemotherapy or other immunotherapy is not permitted.

Research has shown that EWSR1 immunotherapy is being tested for safety in individuals with Ewing sarcoma and desmoplastic small round cell tumor. Early results suggest that this treatment likely has manageable side effects. The immunotherapy aims to help the immune system target cancer cells while avoiding harm to normal cells.

Some participants will also receive botensilimab and balstilimab. Studies have found that this combination is generally well-tolerated. Specifically, one study showed a disease control rate of 65.4% without major changes in safety, indicating that most participants managed the treatment without severe side effects.

Researchers are excited about EWSR1 immunotherapy for Ewing Sarcoma and DSRCT because it targets the EWSR1 gene, which plays a crucial role in these cancers. Unlike traditional chemotherapy and radiation, which aim to kill cancer cells generally, this treatment focuses on a specific genetic driver of the disease. Additionally, in the combination cohort, the treatment is paired with Botensilimab and Balstilimab, which are designed to enhance the immune response by targeting the CTLA-4 and PD-1 pathways, respectively. This multi-pronged approach could lead to more effective, targeted treatment options with potentially fewer side effects than conventional therapies.

Research has shown that EWSR1 immunotherapy targets a specific genetic change in Ewing sarcoma (ES) and desmoplastic small round cell tumor (DSRCT) cells. This treatment enables the immune system to identify and attack cancer cells while sparing healthy cells. In this trial, participants in the monotherapy cohort will receive EWSR1 immunotherapy alone. Meanwhile, those in the combination cohort will receive EWSR1 immunotherapy along with Botensilimab, which targets CTLA-4, and Balstilimab, which targets PD1. Although human studies provide limited data, similar therapies focusing on specific genes have shown promise in slowing tumor growth and improving patient survival. Botensilimab and Balstilimab have previously strengthened the immune response against tumors in other cancer types. Together, these therapies could offer new hope for patients with these aggressive cancers.⁴⁶⁷⁸⁹