We are developing a portfolio of compounds that exploit disrupted metabolism and oxidative stress in aggressive cancers. Our pre-clinical discovery and testing programs utilize advanced cell, tissue and animal models to identify new candidate compounds to transition to IND enabling studies with the goal of bringing the most advanced and potent molecules to clinical studies.

IND Enabling
Phase 1
Phase 2
Intrapleural Monotherapy
Pleural Mesothelioma
RSO-021 + Paclitaxel
Intrapleural Combination
Metastatic Breast
Metastatic Ovarian
Solid Tumors
Other TBD

About PRX3

  • Mesothelioma with Malignant Pleural Effusion
  • Metastatic Breast Cancer
  • Metastatic Ovarian Cancer

unmet medical needs 

Collectively, rare cancers make up for 25% of cancer deaths. Rare and aggressive cancers present formidable challenges in treatment and management, primarily due to rapid growth to local and distant tissues. A tremendous challenge with rare and advanced cancers is that they are highly resistant to traditional treatments.

Late-stage cancers often result in malignant pleural effusion (MPE) where fluid builds up in the pleural space, the small thin lining of tissue surrounding the lungs. People with mesothelioma and metastatic lung cancer, metastatic breast cancer, and lymphoma are most likely to get MPE. Other causes of MPE include cancer that has spread from the stomach, kidney, ovaries, and colon.

Despite advances in treatment, these metastatic cancers remain challenging to cure, and management largely focuses on maintaining quality of life and treating the disease as a chronic condition. At RS Oncology we have developed RSO-021, a treatment for mesothelioma and metastatic disease with MPE, that is locally delivered to the pleural cavity. RSO-021 has completed Phase 1 clinical trials and has transitioned to Phase 2.

The active pharmaceutical ingredient (API) of RSO-021 is thiostrepton. Thiostrepton has broad anti-cancer activity as evidenced by the study performed by Corsello et al. from the Broad Institute.