This marks the fifth independent clinical validation of the cisplatin DRP®, further supporting its potential to guide individualized treatment decisions across multiple cancer types and platinum-based regimens.

The study analysed gene expression data from 20 metastatic breast cancer patients treated with carboplatin within the Danish Breast Cancer Group (DBCG) cohort. Patients were stratified by their Platin-DRP® score, a transcriptomic biomarker derived from a 205-gene expression signature that quantifies tumor sensitivity to platinum chemotherapy.

Key findings:

• Patients with high DRP scores (>50) experienced significantly longer time to progression (median 6.5 months) compared to those with low scores (≤50; median 2.1 months)
• A 50-point increase in DRP score was associated with a hazard ratio of 0.31 (one-sided p = 0.03), indicating a statistically significant reduction in risk of progression
• These results extend previous validations of the cisplatin DRP® in lung and bladder cancer, now confirming its predictive utility for carboplatin in metastatic breast cancer.

"Our data demonstrate that the cisplatin-derived DRP® can predict benefit not only from cisplatin but also from carboplatin" said Peter Buhl Jesen, CEO of CHOSA Oncology. "This expands the clinical and commercial potential of the Platin-DRP® as a precision-oncology tool for selecting the right patients for platinum therapy- one of the most widely used chemotherapy classes worldwide. Indeed almost 50% of cancer patients receiving chemotherapy are receiving a platinum base regimen"

The study extends CHOSA’s validated cisplatin-response predictor to carboplatin, confirming the potential of the cisplatin-derived DRP® to personalize platinum chemotherapy. These findings reinforce CHOSA’s approach of translating transcriptomic biomarkers into clinically actionable tools that can predict patient benefit from platinum-based treatments

Cisplatin and carboplatin are closely related platinum-based chemotherapies used in 16 different cancer indications including lung and breast cancer.

In breast cancer, these drugs work especially well for a certain type called triple-negative breast cancer (TNBC). TNBC makes up about 1 in 5 breast cancer cases. In the past, people with TNBC would go straight to surgery to remove the tumor. But medical treatments have improved in recent years. Now, many TNBC patients receive a combination of platinum-based chemotherapy and immunotherapy before surgery. This approach can be very effective: about 60–65% of patients have no cancer left in the breast by the time of surgery. These patients usually have better long-term outcomes. However, this benefit is mostly seen in patients whose cancer responds well to the treatment. If the cancer is resistant to platinum-based drugs, the patient may not gain the same advantage, making it important to find out in advance who is likely to respond.

CHOSA has global rights to a patented gene test identifying cancer patients most likely to benefit from treatment with cisplatin and now supported by positive data in carboplatin as well. This tool can help clinicians and patients make more informed decisions about platinum-based chemotherapy: guiding treatment toward those with a high likelihood of response and helping avoid ineffective and potentially toxic therapy for those unlikely to benefit.

The test, based on a 205-gene Platin-DRP® signature, has previously been validated for cisplatin in two independent, blinded lung cancer clinical trial datasets and in a prospective phase 2 breast cancer study. The same predictor was evaluated in a cohort of 20 breast cancer patients treated with carboplatin, to assess whether a cisplatin-derived signature could predict response to its sister compound. The results were statistically significant and supportive - forming the basis of CHOSA’s Poster presentation at the annual ESMO conference.

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 exploring 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 focused on late-stage clinical development of LiPlaCis® and its DRP® drug response predictor to which it has worldwide rights. The cisplatin DRP is the only proven test to foresee and thereby select who to treat and who will benefit from cisplatin. Breast: We have strong phase 2b data in metastatic breast cancer, demonstrating that patients selected by DRP® responded better to treatment; have longer progression-free survival; and maybe even an overall longer total survival than those patients who were identified as unlikely to respond well to the treatment.

Lung: The cisplatin DRP has previously shown its ability to foresee the value of cisplatin therapy in lung cancer. Cisplatin therapy after surgery is a gold standard that increases lung cancer cure, but not always, and until now the doctors do not know who will benefit from cisplatin and who should have something else. This is where the cisplatin DRP is a potential game changer, especially in new neoadjuvant treatment where immunotherapy obtains high efficacy rates when combined with cisplatin doubles. Cisplatin DRP was validated in a blinded retrospective study in two lung cancer patient cohorts receiving cisplatin after surgery to kill remaining tumor cells. Thus, patients with the 10% highest scores had a 3-year survival of 90% whereas the patients with the lowest 10% score had much lower survival with only 40% surviving 3 years1.

Immunotherapy There is a new development that adds further value to our DRP. Cisplatin 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.