Although there is currently little chance to cure the asbestos cancer known as mesothelioma, there are researchers around the world who are hard at work developing new diagnostic and treatment methods for those who are diagnosed with this fatal disease. Since the approval by the Food and Drug Administration of the pharmaceutical Alimta® (pemetrexed disodium) to treat mesothelioma, there have been a number of exciting developments in mesothelioma treatment research.
A team of researchers in Australia has recently discovered a new radiation technique which shows great promise for patients with mesothelioma.
The treatment consists of surgery in most cases, followed by high doses of radiotherapy; according to Dr. Malcolm Feigen, who led the study. It has improved patients’ life expectancy by an average of two years. Currently, the average life expectancy after a mesothelioma diagnosis is 18 months.
“We’ve been very impressed that in most cases there’s a considerable improvement in the activity of the tumor masses that we’ve given high doses of radiotherapy,” said Feigen, who presented his findings to an Australian conference on oncology. He also explained that the results of the treatment were tested by doing PET scans both before and after the radiotherapy, then comparing the results.
Multi-modal therapy – that is, combining one or more of the traditional approaches to cancer therapy in an attempt to maximize the benefits, and reduce the side effects, of each – is one of the most promising courses to battling mesothelioma. A recent publication in the Journal of Clinical Oncology has demonstrated that a three-pronged approach to the treatment of mesothelioma may improve the survival times of patients.
The paper described a study in which a team of scientists, headed by Memorial Sloan-Kettering’s Lee M. Krug, looked at 77 patients, each diagnosed with Stage I, Stage II or Stage III mesothelioma. Patients had had no previous surgery, displayed adequate lung function, and were either fully active or restricted only from strenuous activity. The study was part of a Phase II clinical trial to assess the efficacy of combating mesothelioma with a three-part treatment consisting of chemotherapy, surgery and radiation therapy.
First, Krug and the other researchers administered chemotherapy to all of the patients. Several of them, after completion of the chemotherapy, showed a complete disappearance of all clinical symptoms, although some mesothelioma cells still remained without displaying symptoms. Fifty-four patients then went on to undergo surgical resection to remove the diseased areas of their lungs, mesothelium and diaphragm. Forty-four of those patients underwent post-surgical radiation therapy.
Patients who had completed all three levels of therapy showed a median survival time of 29.1 months, and a two-year survival rate of 61.2 percent, whereas the median survival rate of all study patients, including those who had only one or two rounds of treatment, was 17 months. Based on the results of this study and other ongoing research, trimodality therapy is emerging as an effective way to extend the lives of mesothelioma patients.
Another promising study looked at 52 patients with epithelioid malignant mesothelioma and examined their cells for the presence of a biological marker called neurotensin (NTS) and its cognate receptor (NTSR1). NTS has been connected with several biological functions which help cancer to progress throughout the body, and has been identified in such cancers as colon, prostate, pancreas and breast, in addition to mesothelioma.
Neurotensin is made up of 13 amino acids; the cognate receptor provides the genetic coding for the receptor molecule that binds to it. The researchers found the presence of NTS expression in 71.1 percent of the patients studied, and NTSR1 in 90.4 percent. Expression of NTSR1 did not have any significant impact on survival rates or durations; the presence of NTS, however, did negatively affect prognosis.
Patient with less than 10 percent NTS expression had a median survival rate of 29.8 months, where those with 10-50 percent had median survival rates of 18.4 months. The numbers dipped even lower for those with the 50 percent mark of NTS expression, with median survival of 11 months.
Although this research is not specifically applicable to developing a cure for mesothelioma, the information gleaned from the study can be useful in developing specifically targeted drugs, as well as in matching mesothelioma patients to the most potentially successful treatments for their particular case.
Clinical trials can help further the search for new, effective mesothelioma drugs, and Transgene, a biotechnology company, has recently announced that it is spearheading the Phase II trial of a product called Vero-IL2 for the treatment of mesothelioma.
Vero-IL2 consists of an immortal cell line genetically modified in order to produce interleukine-2, which was shown during Phase I trials to be effective on spontaneous tumors through animal testing in Europe.
Phase II trials started in the spring of 1998 in the treatment of advanced melanoma, and Transgene recently announced that it will begin Phase II clinical trials focused specifically on mesothelioma, as well. Transgene’s Phase II clinical trial will evaluate the efficacy of subcutaneous injections of MVA-Muc1-IL2 as a single agent. Like mesothelioma, metastatic renal cell carcinoma is characteristically unresponsive to chemotherapy. Standard therapy, with immunomodulators, induces objective responses in approximately 15-20 percent of patients and higher response rates in some patients with favorable prognosis factors.
Although a diagnosis of mesothelioma is understandably devastating, patients and their caregivers can take heart in the number of clinical trials and other research initiatives that are being undertaken around the world, and the advances that the researchers are continuing to make in the ongoing battle to accurately diagnosed and effectively treat mesothelioma.