Researchers continually find ways
to treat diseases that seem counter-intuitive to the rest of
us. There are hundreds of clinical trials underway at any
given time. Clinical trials are research programs that are
approved for trial on humans. These trials are restricted to
people who meet inclusion and exclusion criteria for that
specific study. Clinical trials conducted through four trial
phases, each involving a larger number of participants. The
fourth phase is a post marketing study.
Several clinical trials are using gene therapy to stimulate
immune responses in humans. One treatment in Phase I involves
injecting a dose of a gene therapy involving a virus thymidine
kinase into the intrapleural space (between the two pleural
mesothelial membranes that line the lungs and ribcage) twice
daily for 3 days. This treatment showed sufficient promise in
the treatment of pleural mesothelioma to recommend it for
Phase II testing. Several other gene therapy trials by
different groups of researchers use variations of gene therapy
with promising results. These trials involved patients with
localized pleural mesothelioma.
A
double-blind study in Phase II Trial will compare the results
of administering the combination of Gemcitabine and Cisplatin
with, and without Bevacizumab, a drug that inhibits the growth
of blood vessels that can nourish new cancer cells in the hope
that the tumor will shrink.
Pemetrexed combined with Cisplatin was compared to Cisplatin
alone in a Phase III trial involving patients with metastatic
pleural mesothelioma (MPM). The combination of both drugs with
the addition of vitamin B12 and folic acid “resulted in
superior survival time, time to progression, and response
rates…” Adding the vitamins reduced toxicity.
Another study in Phase I involves Pemetrexed and Carboplatin
in patients with MPM. During Phase I some of the patients
experienced toxicity related to the dosage, however, 70% of
the patients experienced improvement in their symptoms after
only two courses of treatment. Time to progression was delayed
305 days (about ten months) and median survival time 451 days
(about fifteen months.)
Photodynamic therapy is another approach that is currently
being studied. Patients are pretreated with light-sensitive
molecules that cause the cancer cells to become sensitive to
light. During surgery, these cells are exposed to light of a
specific wavelength. Though there have been positive results,
this treatment also requires more study.
In
comparison, the patients who qualified for these clinical
trials had a life expectancy of six to nine months at the time
they entered the trials. While there is still a long way to
go, scientists are working to find the key to curing
mesothelioma. In the past surgery was done as a palliative
treatment.
Fifteen years ago researchers were hopeful that surgery
combined with chemotherapy, radiation therapy would provide
more significant results than each give separately. Today,
therapy combining surgery with chemotherapy, photodynamic
therapy and gene therapy are producing encouraging results.