Researchers have made significant advances in the treatment of metastatic malignant melanoma ? one of the most difficult cancers to treat successfully once it has started to spread.
The new study to be presented at Europe’s largest cancer congress, ECCO 15 ? ESMO 34, in Berlin on Thursday.
In the phase I extension study, researchers have seen rapid and dramatic shrinking of metastatic tumours in patients treated with a new compound that blocks the activity of the cancer-causing mutation of the BRAF gene, which is implicated in about 50% melanomas and 5% of colorectal cancers.
In new results from 31 melanoma patients with the BRAF mutation who were treated with 960mg of PLX4032 twice a day, 64% (14) of the 22 patients who could be evaluated so far met the official criteria for partial response (this involves the diameter of tumours shrinking by at least 30% for at least a month). A further six of the 22 patients also showed a response, but, at the time of the congress presentation, it was too early to say whether the tumours would shrink far enough to meet these criteria.
Dr Paul Chapman, an attending physician on the Melanoma/Sarcoma service at Memorial Sloan-Kettering Cancer Center (New York, USA) and who was one of the leaders of the trial, told a news briefing: “We are very excited about these results. Of the 22 patients we have been able to evaluate so far, 20 have had some objective tumour shrinkage. This is impressive as they all had metastatic disease and most of them had failed several prior therapies. A lot of these patients were pretty sick but many of them had a significant and rapid improvement in the way they function. We’ve had patients come off oxygen and we’ve got several patients who have been able to come off narcotic pain medication soon after starting treatment.”
The trial is investigating PLX4032 in patients with the BRAF mutation, and results from the first 55 patients were reported at a cancer meeting earlier this year.
Dr Chapman said it was too early to be talking about a cure for advanced melanoma, but that this drug had potential. “Most of us think that a drug like this would ultimately be part of the regimen, but that we might need additional drugs with it to complete the cure. Right now we are seeing dramatic responses but it’s too early to say whether we’ve actually cured people because most patients still have evidence of some level of tumour on their skin. I think this is a huge step forward; whether or not it will be sufficient by itself really remains to be seen.”
Source: European CanCer Organisation, Germany