Chosa Oncology AB: CHOSA receives 94 tumour samples from US patients to validate Platin-DRP® in lung cancer chemo-immunotherapy

The samples represent patients treated with platinum chemotherapy in combination with a PD-1/PD-L1 inhibitors like Keytruda and Opdivo. The tumour samples will undergo RNA analysis at CHOSA's laboratory partner, after which the resulting gene-expression data will be used to calculate individual Platin-DRP® scores and assess their association with patients' treatment outcomes including survival.

Mount Sinai study builds on encouraging clinical results

The retrospective Mount Sinai study is an important next step in the clinical development of Platin-DRP® and follows encouraging results from the EORTC/ETOP SPLENDOUR study. In that study, Platin-DRP® was shown to significantly identify patients with advanced NSCLC who derived greater benefit from platinum-based chemotherapy. Using the predefined 50% threshold in the pooled cohort, patients with high Platin-DRP® scores had a median overall survival of 16.9 months, compared with 5.5 months for patients with low Platin-DRP® scores.

The Mount Sinai analysis will extend this work into the increasingly important treatment setting where platinum chemotherapy is combined with PD-1/PD-L1 immunotherapy. This may provide important evidence on whether Platin-DRP® can identify patients who are particularly likely to benefit from this treatment combination.

Platinum chemotherapy remains a cornerstone of lung cancer treatment

Platinum-based chemotherapy remains a fundamental component of treatment for advanced NSCLC and is frequently administered together with PD-1/PD-L1 inhibitors. While these combinations have substantially improved outcomes for many patients, not all patients derive the same benefit from platinum chemotherapy.

A clinically validated predictor of platinum sensitivity could therefore help identify patients most likely to benefit from platinum-containing treatment while potentially avoiding ineffective chemotherapy and its associated toxicity in patients unlikely to respond.

"We are very pleased to have received these 94 tumour samples from Mount Sinai. The results from the EORTC/ETOP SPLENDOUR study provided important clinical evidence supporting the predictive potential of Platin-DRP® in lung cancer, and this new study gives us an opportunity to take the next step by evaluating Platin-DRP® in patients receiving platinum chemotherapy together with immunotherapy. said Peter Buhl Jensen, CEO of CHOSA Oncology

"The combination of platinum chemotherapy and PD-1/PD-L1 inhibitors is now an important part of the treatment landscape in lung cancer. If Platin-DRP® can identify the patients most likely to benefit from this combination, it could have significant clinical and commercial potential. We expect to have the first results from the Mount Sinai analysis in the first quarter of 2027."  Peter Buhl Jensen further commented.

Expected read-out in Q1 2027

CHOSA expects the RNA analysis and initial clinical outcome analysis to be completed with a first read-out anticipated in the first quarter of 2027.

The Mount Sinai collaboration is part of CHOSA's broader strategy to establish Platin-DRP® as a clinically useful precision-oncology tool for selecting patients for platinum-based treatment across multiple cancer types and treatment combinations.

For more information please contact:

Peter Buhl Jensen, CEO

peter@chosa.bio

+ 45 21 60 89 22

About CHOSA Oncology AB
CHOSA Oncology is a precision oncology company developing Platin-DRP®, a gene expression-based biomarker that predicts response to platinum-based chemotherapy. By identifying patients most likely to benefit, CHOSA aims to improve outcomes and optimize treatment selection in cancer care.

Background

Cisplatin and its sister molecule carboplatin have been cornerstones in lung cancer therapy 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 Platin-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 exploring the predictive potential of Platin-DRP 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 and potentially confirm its utility across both drugs. Future research will also aim to determine whether Platin-DRP can predict the effectiveness of platinum drugs combined with PD-1/L1 inhibitors. CHOSA Oncology AB is an oncology biotechnology company led by an experienced international team with expertise in oncology, drug development, clinical trials, regulatory affairs, and business development. CHOSA intends to enter into partnership or sublicensing agreements for LiPlaCis® and the DRP®.

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

CHOSA is focused on its Platin-DRP® drug response predictor, to which it holds worldwide rights. Platin-DRP is a validated test designed to help identify patients most likely to benefit from cis- and carboplatin treatment. Most recently, CHOSA presented results from the ETOP/EORTC SPLENDOUR study demonstrating that patients with advanced lung cancer predicted to benefit from platinum therapy achieved a median overall survival of 16.9 months compared with 5.6 months for patients predicted not to benefit.

Breast: Strong phase 2b data in metastatic breast cancer have shown that patients selected by DRP® responded better to treatment, had longer progression-free survival, and may also have achieved longer overall survival than patients identified as unlikely to respond well.

Lung: Platin-DRP has also demonstrated its ability to predict the benefit of adjuvant cisplatin in lung cancer. Cisplatin treatment after surgery remains a gold standard that can improve cure rates, but doctors have not had a validated tool to identify which patients are most likely to benefit. This is where Platin-DRP may become a game changer, particularly in newer neoadjuvant settings where immunotherapy has shown high efficacy in combination with platinum doublets. Platin-DRP was validated in a blinded retrospective study in two lung cancer patient cohorts receiving cisplatin after surgery to eliminate residual tumour cells. Patients with the 10% highest scores had a 3-year survival of 90%, whereas patients with the lowest 10% scores had a 3-year survival of only 40%¹. In 2026 CHOSA in collaboration with key opinion leaders in lung cancer showed the Platin-DRP in advanced clearly separated the patient with a sensitive cancer from a platin resistant tumor with a median survival of 16.9 months in the former group vs only 5.5 months in the latter2.  

Immunotherapy Cisplatin and carboplatin have often been shown to activate the immune system, potentially making "cold" tumours more susceptible to PD-1 inhibitors. This synergy may be important not only in lung cancer, but also in breast cancer, bladder cancer and head & neck cancer. In the growing PD-1 inhibitor market, CHOSA's approach may offer the ability to predict whether platin can provide synergy with PD-1 inhibition, potentially creating a meaningful advantage for treatment selection and future partners.

1) Buhl et al PLOS One doi: 10.1371/journal.pone0194609 2) ESMO Open Volume 11, Supplement 3, 106773, April 2026

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.