Complex sentence: As no effective treatment for PAM has been found, research to the develop a therapeutic is searching for what factors, specific to "N. fowleri", make it pathogenic; virulence factors may be targeted by drugs.
Split into simpler sentences: As no effective treatment for PAM has been found, the development of a therapeutic is an area of research interest. Currently, much work is being done to determine what factor specific to "N. fowleri" makes it pathogenic and if these virulence factors can be targeted by drugs.