Lack of colitis side effect with CXD101 and nivolumab combination therapy in CAROSELL Phase II clinical trial of MSS CRC patients
Oxford, UK, 14 Jan 2020 – Celleron Therapeutics, the UK-based company developing novel medicines for cancer patients, announced today a lack of drug-related colitis in the safety data for its CAROSELL Phase II clinical trial. CAROSELL is testing the immune-oncology agent nivolumab (Opdivo) in combination with CXD101, in patients suffering from advanced micro-satellite stable colorectal cancer (MSS CRC).
Colorectal cancer is the second most common tumour type in women, and the third most common in men, globally. The approximate five year survival rate for colorectal cancer patients in the United States (all stages included) is 65%. Survival is inversely related to stage: approximate 5-year survival rates are 95% for patients with stage I disease, 60% for those with Stage III disease, and 10% for those with Stage IV (metastatic) disease. Two agents have been approved for third line management of advanced colorectal cancer, namely regorafenib (Stivarga) and trifluridine-tipiracil hydrochloride (Lonsurf).
A subset (5%) of colorectal cancer has deficient DNA mismatch repair (dMMR or microsatellite instability, MSI). These tumours have high expression of checkpoint proteins (PD-1 and PD-L1), which interfere with the body’s normal anti-tumour T-cell response. By disabling these proteins, immune checkpoint inhibitors (ICI) such as nivolumab allow the immune system to function properly, and T-cells to kill tumour cells.
However, for the majority of patients the microsatellite phenotype is stable (MSS), antigen presentation is decreased and the tumour is resistant to checkpoint inhibition. There remains a very significant unmet clinical need to find novel agents, singly and/or in combination, for the treatment of these late-stage patients.
CAROSELL tested CXD101 in combination with nivolumab in MSS colorectal cancer, a clinical design which reflected compelling pre-clinical results suggesting that CXD101 and ICI drugs work together to re-engage recognition of tumours by the immune system, colloquially, to turn ‘cold tumours hot’.
Enrolment to the Phase II study completed in May 2019, and all ongoing subjects have now received study treatment for at least 6 months. Interim analysis of 45 evaluable MSS CRC subjects saw that 22 (49%) exhibited durable disease control (stable disease plus partial response), as determined by CT scan tumour measurements (iRECIST). The clinical activity compares favourably with the reported activity of marketed products such as regorafenib and Lonsurf.
The most frequent observed Adverse Events were fatigue, nausea, and cytopenias. All AEs were manageable. There were no deaths or discontinuations from the study. However, it was noted that there were no reports of drug-related colitis, which is a very debilitating side effect of nivolumab treatment. The incidence of immune-mediated colitis is usually apparent in a significant proportion of patients depending on the type of immune checkpoint inhibitor. The improved safety profile seen in CAROSELL may result from the anti-inflammatory action of CXD101. This will be investigated in subsequent clinical studies combining CXD101 with immune checkpoint inhibitors.
Professor David Kerr CBE, Founder and Chief Medical Officer, Celleron Therapeutics and Professor of Cancer Medicine, University of Oxford commented:
“There is good evidence to suggest that disease stabilisation and control can lead to improved survival in patients such as ours, who have progressed despite receiving all conventional chemotherapy. Further trials will be required, but this early read out is most encouraging. In particular, our clinical investigators found the combination treatment to be well tolerated, leading us to speculate that CXD101 may suppress some of the side effects of nivolumab ”
Professor Nick La Thangue, Chief Executive and Founder of Celleron Therapeutics, and Professor of Cancer Biology in the Department of Oncology at Oxford University, commented:
“This is a very interesting clinical observation which points to a novel anti-inflammatory role of CXD101, resulting in a reduction in the debilitating colitis side effect often seen with agents like nivolumab. Together with the disease stabilisation and control, CXD101 is highly likely to find important clinical utility”.
About Celleron Therapeutics
Celleron Therapeutics is a biopharma company advancing a clinical and pre-clinical pipeline of novel therapies for different cancer indications. The company is a spin-out from Oxford University and located on the Oxford Science Park, UK. Celleron Therapeutics has built a proprietary platform around epigenetic control and immune modulation, providing its drugs with a two-pronged attack on cancer.
Celleron Therapeutics’ focus is on those cancers where there is still an unmet need for long-term disease control. It is hoped that not only will patients volunteering for our clinical trials benefit directly, but the results from these studies will ultimately allow the general use of more effective, safer medicines. Our goal is not only to treat cancer, but improve quality of life during therapy by reduction of side effects.
Celleron has a global license partnership with Astra Zeneca and is also initiating new trials in China. The company secured investment in 2016 from a consortium of Asian investors. For more information see www.cellerontherapeutics.com
CXD101 is Celleron Therapeutics’ next generation epigenetic immune-regulator representing a class of drug that kills cancer cells by blocking certain vital functions involved in gene expression (histone–deacetylase [HDAC] inhibitor) and reactivates the patient’s immune system so that cancer cells can no longer evade immune recognition.
The European Medicines Agency (EMA) has previously granted CXD101 Orphan Drug Designation as single agent therapy, based upon early-phase trial efficacy seen in relapsed or refractory Peripheral T-Cell Lymphoma (PTCL) patients. A PTCL Phase II trial will start in 2020 in China.
Celleron Therapeutics is also leading an investigator-led Phase Ib/II clinical trial in diffuse large B-cell lymphoma (DLBCL) patients who have failed on chemotherapy, called PLACARD, which is testing the combined effect of CXD101 and pembrolizumab.