AA (or secondary) amyloidosis is the second most common
form of the disease worldwide. With its associated chronic
inflammatory diseases (e.g., rheumatoid arthritis, Crohn’s
disease, and familial Mediterranean fever), amyloid deposition
is very gradual. The survival rate is often more than 10
years, particularly with treatment for kidney disease. In contrast,
untreated infections such as osteomyelitis or tuberculosis
can cause a quicker accumulation of amyloid.
In all cases, the mainstay of therapy is to address the underlying
infection or inflammatory condition. This can slow
or stop the progressive buildup of amyloid by reducing the
circulating precursor protein, serum amyloid A.
Moreover, an oral drug called eprodisate (Kiacta) has been
found to inhibit the formation of amyloid fibrils. Kiacta prevents
serum amyloid A from interacting with other molecules
that facilitate its misfolding into amyloid. Clinical trials have
shown that, because the amyloid can no longer be formed
and deposited, this treatment can effectively slow or stop
the deterioration of kidney function. It is anticipated that
Kiacta will be approved for widespread use in the next few
years, following the confirmation of its efficacy through international
studies.
For those patients with renal failure, dialysis and kidney
transplantation are possible treatments. However, as with
kidney transplants for AL amyloidosis, if the source of the
abnormal protein is not addressed, amyloid may eventually
appear in the donor kidney.