(RxWiki News) Part of the process of developing and testing drugs involves seeing if treatments work in similar conditions, and science is full of surprises.
Recently scientists found that not only did a drug work for another disease, but they learned something new about how the immune system works.
A study looking at the family of lymphoma known as cutaneous skin cell lymphoma showed a valid use of low dose Campath (alemtuzumab) in treating types of this cancer, leukemic cutaneous T cell Lymphoma (L-CTCL) and mycosis fungoides.
The results were especially notable for the effective treatment in patients with cancers that had not responded to any other treatments, a condition known as refractory L-CTCL.
"Ask your oncologist about Campath."
The authors of the study noted that the therapy was particularly impressive because the treatment reduced numbers of cancerous T cells without causing any impairment of the immune response. Surprisingly, though, the expected increase of skin infections in patients during the course of therapy never happened.
Unfortunately, this meant that the drug therapy did not show any effect in patients with mycosis fungoides, since T cells in that condition are already embedded in the tissue and do not enter the bloodstream.
With further study the researchers observed that some T cells stay in the skin and are unaffected by the drug's circulation in the blood. The T cells remain functional and provide an active immune response in their neighborhood, whether that was the intestinal system or the skin.
This research also shows a new understanding of the previously held theory that Campath destroys all immune cells, including both T Cells and B cells, since this population of resident T cells, distributed all over the body, was unaffected by the drug.
The drug was given at lower doses in this experiment than when used as a treatment for chronic lymphocytic leukemia.
"We noticed that our patients were not getting infections, and we looked in the skin. We saw healthy T-cells remaining there despite the fact that there were no T-cells in the blood," said Rachael A. Clark, M.D., Ph.D. "We used to believe that most T-cells responsible for protecting against infection were in the bloodstream. But we now realize that highly protective T-cells also inhabit tissues such as the skin, lungs and gastrointestinal tract. It is these tissue resident T-cells that are critical in protecting us from infection on a day-to-day basis."
Campath was initially approved by the FDA in 2001 for the treatment of chronic lymphocytic leukemia, and approval was expanded to treatment of B-CLL in 2007.
Campath targets mature immune cells only, avoiding permanent damage to immune function as cells are continually replaced. Prices for Campath range from $10-30,000 per year depending on dosage.
The study was published in the journal Science Translational Medicine.
The authors of this study did not disclose any financial conflicts of interest.