CHOSA files new patent application to predict which patients may benefit from platinum chemotherapy and immunotherapy

The English text is an unofficial translation. In case of any discrepancies between the Swedish text and the English translation, the Swedish text shall prevail.

June 25, 2025 – CHOSA announces the submission of a PCT international patent application to the European Patent Office for a novel method to predict which cancer patients are likely to respond to a combination of platinum-based chemotherapy and PD-1/PD-L1 immunotherapy.

The new patent application relates to an expanded/extended use of CHOSA’s proprietary Drug Response Predictor (Platin-DRP®) to predict the synergistic effect of combining platinum chemotherapy with immunotherapy.

The application claims the use of Platin-DRP® to identify patients most likely to benefit from treatment combinations involving platinum drugs—such as cisplatin, carboplatin, or LiPlaCis®—and PD-1/PD-L1-targeting immunotherapies.

This combination is widely used, particularly in lung, bladder, breast, and head and neck-cancers. Platinum drugs can help convert "cold" tumors into "hot" ones, enhancing the effectiveness of immunotherapy. However, only about half of patients currently benefit from such combination treatments.

CHOSA’s test aims to guide treatment decisions by predicting who is likely to respond to this combination. It is based on a 205-gene signature, which has already shown positive results in independent cisplatin studies in lung and breast cancer and in a recent prospective breast cancer trial with carboplatin.

The patent application expands CHOSA’s global rights from platinum monotherapy prediction to also include platinum - immunotherapy combinations - addressing a major unmet need in oncology.

For additional information, contact:
Peter Buhl Jensen, CEO
Peter@chosa.bio
+ 45 21 60 89 22

Background

Cisplatin and its sister molecule carboplatin have been cornerstones in lung cancer chemotherapy for decades. Despite advances in immunotherapy, platinum drugs remain critical in treatment regimens, including combinations with PD-1/L1 inhibitors. While numerous efforts to predict cisplatin efficacy have failed, the Cisplatin-DRP, based on a 205-gene biomarker signature, has shown promising results in other settings, including adjuvant therapy in NSCLC and progression-free survival in breast cancer.

As previously announced CHOSA is also validating the predictive potential of the Cisplatin-DRP not only in cisplatin-treated patients but also in those treated with carboplatin in lung cancer. Data from the SPLENDOUR trial provides a unique opportunity to validate this tool in a large cohort, potentially confirming its utility across both drugs. Future research will aim to determine whether the Cisplatin-DRP can predict the effectiveness of combinations of platinum drugs with PD-1/L1 inhibitors.

CHOSA in short

CHOSA Oncology AB is an oncology biotechnology company led by a proven international team with veteran specialists in oncology; drug development; running clinical trials; regulatory expertise; and business development. CHOSA intends to enter into agreements for partnership or sublicensing of LiPlaCis® and the DRP®.

About Cisplatin-DRP, a test to predict if cisplatin treatment is likely to be successful

CHOSA is advancing its cisplatin Drug Response Predictor - Cisplatin-DRP®, a clinically validated test that identifies which patients are most likely to benefit from cisplatin and carboplatin treatment. The DRP holds global rights and is the only proven tool to guide platin use across cancer types.

In metastatic breast cancer, Phase 2b data show that DRP-selected patients respond better and have longer progression-free survival.
In lung cancer, the DRP has predicted benefit from cisplatin after surgery - especially relevant now that cisplatin is increasingly combined with PD(L)-1 immunotherapies in neoadjuvant settings. In two independent studies, patients with the highest DRP scores had a 3-year survival rate of 90%, compared to just 40% among those with the lowest scores1.

The DRP may help guide combination treatments by predicting who will benefit from platinum-immunotherapy synergy.

ImmunotherapyThere is a new development that adds further value to our DRP. Platin has often been shown to activate the immune system (making cold tumors hot), which makes tumors susceptible to PD1 inhibitors. This synergy is particularly important but not limited to the treatment of lung cancer, bladder cancer, and head and neck cancer. In the ever-growing PD1 inhibitor market, where competition is fierce, our company stands out with the ability to predict if cisplatin will provide synergy with PD1. This can give the PD1 selling companies a significant competitive advantage.

1) Buhl et al PLOS One doi: 10.1371/journal.pone0194609

DRP® is a registered trademark of Allarity Therapeutics, Inc., and is used under license granted to CHOSA. LiPlaCis is in-licensed from Allarity Therapeutics Ltd (previous Oncology Venture ApS) and LiPlasome Pharma ApS.

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