An experimental drug has produced remarkable results when tested on a wide range of cancers.
Larger trials of the drug are now planned
Patients with advanced breast, prostate, lung, ovarian, colon, pancreas and connective tissue cancers all benefited from taking the drug, called 2C4.
The drug, given the trade name Omnitarg, consists of a protein called a monoclonal antibody which gives a boost to the body's immune system.
Specifically, it targets a signalling pathway common to many different cancers that stimulates tumour growth.
This drug effectively shrank tumours in several completely different types of cancer
Scientists are excited because dramatic results were seen in a preliminary Phase I trial.
The aim of these trials is simply to see if the drug is safe - not whether it is effective.
But in this case the drug immediately began to produce impressive results.
Dr David Agus, who led the trial at the Cedars-Sinai Medical Centre in Los Angeles, said: "What's interesting is that this drug effectively shrank tumours in several completely different types of cancer in early stage clinical trials.
"This tells us that the drug targets a growth-signalling pathway in cancer cells that is common in many solid tumours."
In the study, 21 patients with advanced cancers received Omnitarg by infusion at three week intervals.
A total of 19 patients completed at least two cycles of treatment, and two died at the outset due to complications of their disease.
The researchers found that in 42% of the treated patients tumours either shrank by up to 50%, or stopped growing for a given time period.
Three patients achieved partial remission - one with ovarian cancer, one with prostate cancer and one with pancreatic cancer.
The ovarian and pancreatic patients remain in remission and have now been receiving Omnitarg for over a year.
Five additional patients - three with prostate, one with lung and one with ovarian cancer - stabilised for at least three months after two treatment cycles.
Dr Agus, who presented the results at a meeting of the American Society of Clinical Oncology in Chicago, said: "To see results that show activity in a Phase I safety trial is remarkable, especially since these patients were in the
advanced stages of their disease and had no other treatment options open to them."
Dr Elaine Vickers, science information officer at Cancer Research UK, said: "The results from this trial look very promising, and the potential of monoclonal antibodies has already been demonstrated with the approval of drugs such as Herceptin and Rituximab.
"However, this was only a small trial, larger trials involving many more patients are needed before a definitive answer on the effectiveness of Omnitarg can be reached."