OREANDA-NEWS. Chronix Biomedical, Inc., a developer of blood-based molecular diagnostics, highlights the presentation of data from an independently-conducted, proof-of-concept study that show that its liquid biopsy blood test can be used to predict therapeutic response to immunotherapy. The data were presented yesterday in the form of a poster at the American Society of Clinical Oncology ('ASCO') Annual Meeting in Chicago.  

Chronix Biomedical and its scientific collaborators have developed a proprietary copy number instability (CNI) score based on measuring changes in tumor cell-free DNA ('cfDNA') from blood samples. The study was designed prospectively to assess whether this CNI score could make an early prediction of whether a patient will respond to immunotherapy.

The context of this development is important, given the significant advances that have been made in the treatment of cancers such as melanoma and non-small cell lung cancer by the introduction of immune checkpoint inhibitors. While these new agents can generate profound responses in some patients, they are not effective in others, and there is, as yet, no reliable way to identify the likely responders in advance. This creates a challenge for doctors, given the high cost of the new agents and wider healthcare budget limitations. Chronix has therefore identified an unmet medical need for a reliable early predictor of response to cancer therapy.

The study presented by Chronix and its collaborators covers data from a study conducted in 23 patients, one with stage 3 cancer; the rest with stage 4 cancer. The patients had in total eight different forms of cancer: melanoma, renal, gastrointestinal, lung, breast, ovarian and pancreatic cancer, and sarcoma. Those with melanoma and renal cell carcinoma were treated with interleukin-2, while the others received anti-PD1 therapy1, mostly in combination with chemotherapy. The investigators examined plasma DNA from the patients before treatment (at baseline) and after one or two cycles of immunotherapy and monitored changes in the CNI score.   

The study compared the performance of CNI against RECIST 1.1 and irRECIST, two standard methods for assessing treatment outcomes. Chronix's CNI analysis correctly identified 82% (14 of 17) patients with progressive disease or a partial response after the first cycle, rising to 88% (15 of 17) after the second cycle of immunotherapy, demonstrating strong concordance with RECIST. The authors conclude that the CNI score could predict whether a patient would respond to immunotherapy some 3-12 weeks prior to when it would otherwise be possible to by conventional methods (scans).     

Dr Nick Plowman, Senior Consultant Physician and Clinical Oncologist to St. Bartholomew Hospital and The Hospital for Sick Children, London, UK, and a scientific advisor to Chronix Biomedical, said:

"These results are highly encouraging and supportive of changes of CNI being a useful tool for predicting patients' responses to immunotherapy.  Performing a simple blood test to identify patients responding to therapy earlier than is currently possible with imaging, should confer a significant improvement in care by allowing clinicians to assess response and, if necessary, discontinue ineffective treatments sooner. Given the limitations on healthcare resources there are also important health economic arguments for such methodology. "

Separately, Chronix Biomedical has published other clinical data supporting the ability of CNI to predict therapeutic response to radiotherapy in patients with oropharyngeal cancers at ASCO. The findings of this blinded study were that cfDNA has a high sensitivity in even small head and neck cancers and that CNI has furthermore the potential to be a valuable addition to patient risk stratification and monitoring for relapse in this disease setting.

Earlier this year, Chronix Biomedical presented data supportive of CNI as a predictor of therapeutic response to chemotherapy at the American Association for Cancer Research ('AACR') Annual Meeting. The study evaluated the ability of CNI to predict response to cytotoxic chemotherapy in five types of metastatic cancer and correctly stratified patients as either responders or non-responders in 92% (22 of 24) of cases compared to RECIST, again demonstrating strong concordance.  

Chronix has now published data that show CNI analysis can predict treatment outcomes in patients undergoing immunotherapy, chemotherapy and radiotherapy in different cancers, suggesting it could have a broad clinical utility.

Chronix Biomedical's CEO, Dr Howard B. Urnovitz, commented: 

"We are pleased to add these data to the body of clinical evidence supporting copy number instability as a monitoring test and early predictor of therapeutic outcomes to cancer treatments."

About Chronix Biomedical

Chronix Biomedical, Inc. is a US-based molecular diagnostics company developing blood tests primarily for the screening and monitoring of cancer. Chronix already offers supplemental screening evaluation tests based on copy number instability for breast and prostate cancer through its own certified laboratories in G?ttingen, Germany.

RECIST 1.1 and irRECIST

Response Evaluation Criteria In Solid Tumors "RECIST" is an internationally recognised voluntary standard used to assess solid tumor response to treatment. RECIST aims to define tumor response and identify a response, disease stabilisation or progression. Immune-related Response Evaluation Criteria In Solid Tumors "irRECIST" is specific to the assessment of the effect of immunotherapeutic agents.

1 Bristol-Myers Squibb's Opdivo ® (nivolumab) or Merck & Co's Keytruda® (pembrolizumab).