Penetrium Bio Unveils Evidence for Controlling Cancer Drug “Pseudo-Resistance” ... Prostate Cancer Trial Also Advances

[Financial News] A clinical strategy aimed at improving treatment response by adjusting the pathological environment around a tumor, rather than switching drugs, is taking shape for patients who do not respond to existing cancer drugs. As Penetrium Bio continues combination treatment in prostate cancer patients, it has presented nonclinical data at an international conference supporting the related mechanism of action. Whether this strategy for controlling so-called “pseudo-resistance” through the pathological microenvironment can improve treatment responses in actual patients will be a key focus of future clinical trials.
On the 12th, anticancer drug developer Penetrium Bioscience Inc. said that Professor John Isaacs of Newcastle University in the UK had presented nonclinical results for the investigational formulation CP-RhA01 at ACR Convergence 2026, held in Orlando, on the 9th (local time). Professor Choi Jin-ho of Dankook University and Jin Geun-woo, CEO of Penetrium Bio, also participated as co-authors.
The researchers said that in an animal model of arthritis, combining Penetrium with the standard treatment methotrexate (MTX) improved arthritis indicators compared with MTX alone and inhibited the formation of pannus, a pathological stromal tissue. Indicators related to pathological fibroblast activity, including FAPα and α-SMA, as well as those related to the extracellular matrix (ECM), also decreased.
Penetrium is focused on how cancer-associated fibroblasts (CAFs) and the extracellular matrix, which accumulate abnormally around cancer cells, can impede drug delivery and immune-cell access, reducing treatment efficacy. Unlike the biological resistance of cancer cells to drugs, the phenomenon in which the surrounding tissue environment limits treatment response is defined as “stromal pseudo-resistance”; the strategy is to regulate it to enhance the effects of existing drugs.
The dosing schedule for the first patient in a domestic prostate cancer trial has also been completed. The first patient in the Phase 1 trial for metastatic castration-resistant prostate cancer, being conducted at Seoul National University Hospital, completed 12 weeks of combination treatment on November 2. The patient had not responded sufficiently to the existing hormone-targeted therapy enzalutamide and received Penetrium alongside it at the lowest dose, 600 mg per day.
After reviewing the patient’s treatment course, the attending medical team determined that treatment should continue and applied to the Ministry of Food and Drug Safety on the 6th for approval to use the treatment for 180 days. However, the application to extend treatment does not in itself demonstrate the drug’s efficacy or confirm the validity of the clinical trial.
The company is also expanding the scope of its overseas clinical development. Last September, Penetrium Bio received authorization from the U.S. Food and Drug Administration (FDA) to proceed with a Phase 2a trial (Study May Proceed) in patients with recurrent or refractory advanced solid tumors. The company plans to combine Penetrium with existing standard treatments and assess measures including the objective response rate (ORR) by tumor type.
Penetrium Bio Chairman Jo Won-dong said, “This ACR presentation supports, at the molecular and metabolic levels, the principle of controlling pseudo-resistance through the pathological microenvironment—a shared treatment mechanism for cancer and rheumatoid arthritis—presented at the Seoul International Symposium last January. Through domestic prostate cancer and overseas solid tumor trials, we will use objective data to determine whether we can improve responses to existing anticancer drugs across various cancer types.”
[email protected] Jung Sang-hee Reporter