Innovative Cancer Immunotherapy Brings New Hope for Advanced-Stage Patients

Researchers from Singapore's Agency for Science, Technology and Research (A*STAR) and biotech firm Intra-ImmuSG have announced promising results from a Phase II clinical trial of a groundbreaking cancer immunotherapy known as PRL3-zumab. This innovative antibody therapy has demonstrated a safe profile while effectively slowing disease progression in patients with late-stage solid tumors that have not responded to conventional treatments.

PRL3-zumab is a humanized antibody engineered to target PRL3, an intracellular protein that is overexpressed in approximately 80% of solid tumors but absent in healthy tissues. Unlike traditional antibodies that target surface proteins, PRL3-zumab can identify cancer cells by transiently binding to PRL3 when it appears on the cell surface, thereby marking these cells for destruction by the immune system through antibody-dependent cellular cytotoxicity and phagocytosis.

The trial, detailed in the journal Cell Reports Medicine, involved 51 patients with various advanced cancers. The results showed a significant benefit for many patients, with one individual with Stage IV gastric cancer experiencing disease stabilization for more than 13 months—a stark contrast to the typical two-month progression seen with standard therapies. Although the primary focus was on disease stabilization, some patients elsewhere have also demonstrated tumor shrinkage, suggesting broader therapeutic potential.

PRL3-zumab’s development traces back to foundational research by Professor Qi Zeng at A*STAR IMCB, who first identified PRL3 in 1998 as a key player in cancer metastasis and drug resistance. This research led to the creation of Intra-ImmuSG, dedicated to advancing this therapy into clinical use.

The Phase II study highlighted the therapy’s safety, with no serious side effects reported, and utilized a novel analytical method called the Single Evaluable Patient Single Cohort (SEPSC) design. This approach rigorously compared each patient’s progress on PRL3-zumab against their previous treatments. The promising results suggest that PRL3-zumab could serve as a new rescue therapy for patients with treatment-resistant cancers, particularly those who have exhausted existing options.

This therapy’s ability to target intracellular proteins believed to be ‘undruggable’ marks a significant advancement in cancer immunotherapy. It opens new doors for tackling aggressive and rare cancers, offering renewed hope for many patients.

For more detailed information, the study is available in Cell Reports Medicine, and ongoing trials in other countries continue to evaluate the full potential of PRL3-zumab as a versatile treatment option.