Onyvax Reports Early Success with Osteosarcoma Cancer Vaccine
LONDON APR 19, 2005 (Agence de Presse Medicale for Reuters Health) – The private UK biotech company Onyvax on Tuesday reported positive phase l/ll clinical trial results for its cancer immunotherapy ” Onyvax-105″ in children and young adults with osteosarcoma.
The vaccine targets the CD55 antibody that is overexpressed in many types of cancer as part of its defence against immune system attack. The investigational drug was given to 31 pediatric and young adults with high-grade osteosarcoma who had completed best standard therapy.
The results showed that most patients receiving intensive chemotherapy for osteosarcoma could still mount an immune response to the cancer vaccine approach, the company said in a statement.
Although the trial was designed to assess feasibility of immunotherapy rather than efficacy, two patients remained tumour-free more than 4 years later.
Dr. Pritchard-Jones, Professor of Childhood Cancer at the Royal Marsden Hospital, London, and principal investigator of the study, said: “This group of patients has limited treatment options and a very poor prognosis.
“We were pleased to see a high percentage of patients developing immune responses to Onyvax-105, confirming that an immunomodulatory approach is feasible in combination with the intensive chemotherapy that these children and young adults require.
“Moreover, it is very unexpected for any patients at this stage of the disease to remain free of recurrent disease for long.”
The company reported last year that its lead cancer vaccine, Onyvax-P, had doubled progression free survival time in a small nonrandomised study of men with advanced prostate cancer. Further results are expected this year.
Onyvax-105 Shows Promising Results in Osteosarcoma
Researchers affiliated with the UK Children’s Cancer Study Group have reported that a vaccine known as Onyvax-105 (105AD7 ) elicits an immune response in patients with osteosarcoma. The details of this report appeared in the British Medical Journal.[1]
Osteosarcoma is a disease of younger individuals that is treated with surgery, radiation and chemotherapy. However, despite optimal therapy, the majority of patients with advanced disease ultimately relapse. Onyvax-105 is an anti-idiotypic monoclonal antibody that mimics the tumor associated antigen 791/gp72, which was developed by Onyvax Limited.[2] A previous randomized study in patients with advanced colorectal cancer comparing Onyvax-105 to placebo failed to show efficacy, a result attributed to a high tumor burden.[3]
In the UK study, vaccine was administered to 31 pediatric and young adult patients with osteosarcoma after completion of chemotherapy. Significant T-cell responses were observed in 71% of patients. Over 50% of patients showed antigen-specific gamma interferon secretion, and 31% showed an antibody response. The vaccine was described as well tolerated. They also reported that two patients with possible clinical responses continued immunization for two years and are disease-free for over 5 years. The authors propose to carry out a randomized trial to determine if this vaccine is effective.
Comments: It is difficult to know from this trial if Onyvax-105 will be effective in Osteosarcoma or other diseases. This vaccine will need to be tested in randomized trials in patients with minimal residual disease and a high probability of relapse.
References:
[1] Pritchard-Jones, K, Spendlove K, Wilton C, et al. Immune responses to the 105AD7 human anti-idiotypic vaccine after intensive therapy for osteosarcoma. British Medical Journal advance online publication. March 2005;doi:101038/sj.bjc.6602500.
[2] Press release for April 19, onyxax.com
[3] Maxwell-Armstrong, CA, Durrant LG, Buckley TJD, et al. Randomized double-blind phase II survival study comparing immunization with the anti-idiotypic monoclonal antibody 105AD7 against placebo in advanced colorectal cancer. British Medical Journal. 2001;84:1443-1446.
