CHOSA enters into an agreement with a CLIA-certified laboratory partner for Platin-DRP® in the USA - first revenue expected summer 2027

Platinum drugs have historically been among the most active and widely used agents in lung cancer treatment. However, despite their established efficacy, not all patients benefit, and many experience toxicity without meaningful clinical benefit. Platin-DRP aims to identify patients most likely to benefit, bringing platinum therapy into the era of personalized medicine. Worldwide, more than one million lung cancer patients are treated with platinum-based chemotherapy each year.

CLIA provides an established regulatory infrastructure, used by the vast majority of US diagnostic laboratories. CHOSA plans to leverage this infrastructure to commercialize Platin-DRP in the USA through a CLIA-certified molecular diagnostic laboratory.

Clinical evidence from the ETOP/EORTC SPLENDOUR study

The CLIA programme builds on the clinical results from CHOSA's collaboration with ETOP and EORTC. Analysis of samples from the randomized Phase III SPLENDOUR trial included 82 patients with advanced NSCLC treated with cisplatin or carboplatin.

Results presented at the European Lung Cancer Congress in March 2026 showed statistically significant associations between higher Platin-DRP® scores and longer progression-free and overall survival. Using the predefined score threshold, median overall survival was 16.9 months in the high-score group compared with 5.5 months in the low-score group.

Under the agreement, the laboratory will provide development, validation and related laboratory services to prepare Platin-DRP® for clinical use. The programme will establish and document the test's analytical performance and implement the laboratory procedures and quality controls required under CLIA.

CHOSA targets first commercial revenue from Platin-DRP® testing in the summer of 2027, subject to successful completion of analytical validation and implementation of the test under the laboratory's CLIA certification. Additional technical or documentation requirements may arise during the programme and could affect this timeline.

"Securing a CLIA-certified laboratory partner is an important milestone on our commercial journey. We estimate the US market potential at more than 250,000 Platin-DRP® tests per year and we expect 300-500 tests sold in first year"," said Peter Buhl Jensen, CEO of CHOSA Oncology. "Platinum chemotherapy remains central to lung cancer treatment, including modern combinations with immunotherapy, yet patients do not benefit equally. Our ambition is to help physicians make more informed treatment decisions by identifying those most likely to benefit."

Extending validation to platinum chemotherapy combined with immunotherapy

In parallel, CHOSA is conducting a retrospective study with Mount Sinai Hospital in New York to evaluate Platin-DRP® in patients with advanced NSCLC treated with platinum chemotherapy combined with PD-1/PD-L1 immunotherapy.

As announced on October 8, 2026, CHOSA has received 94 tumour biopsy samples from US patients for this study. Gene-expression analysis will be used to calculate individual Platin-DRP® scores and assess their association with treatment outcomes, including survival. The study extends CHOSA's clinical validation into contemporary chemo-immunotherapy regimens, with an initial read-out expected in the first quarter of 2027.

"Together, the SPLENDOUR results, our ongoing Mount Sinai collaboration and the laboratory agreement support the next stage of Platin-DRP® development," Peter Buhl Jensen added. "We are advancing the clinical evidence while establishing the laboratory framework needed for a future commercial testing service."

This information is information that CHOSA Oncology AB is obliged to make public pursuant to the EU Market Abuse Regulation (MAR). The information was submitted for publication, through the agency of the contact person set out above, at 10:35 CET on 4 November.

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 designed to predict 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.

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 platinum-based chemotherapy 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 validate gene expression 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 and high Platin-DRP® scores achieved a median overall survival of 16.9 months on platinum therapy, compared with 5.5 months for patients with low scores.

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 could fill an important gap, 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, in the ETOP/EORTC SPLENDOUR study in advanced NSCLC, patients with high Platin-DRP scores had a median overall survival of 16.9 months, compared with 5.5 months for patients with low scores2.  

Immunotherapy Cisplatin and carboplatin have been shown to stimulate anti-tumour immune responses, 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.pone.0194609 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 (formerly Oncology Venture ApS) and LiPlasome Pharma ApS.