As I have stated in previous posts, the only therapy for BK nephropathy is immunosuppressive reduction, however, this also puts the patient at risk for graft rejection.
At the moment there are several non FDA approved drugs which show promise in counteracting the BK virus. So far they are approved for treatment of several DNA viruses such as Herpes simplex, CMV, Hepatitis. All of these drugs act by inhibiting DNA polymerases effectively halting viral replication.
Each of the following paragraphs will be brief descriptions the specific drugs that may in the future be used for treatment.
Cidofovir:
Cidofovir stops viral replication by inhibiting the viral DNA polymerase. Cidofovir is currently approved for the treatment of CMV-induced retinitis in HIV-infected patients. The CMV virus is very similar to the BK virus in that it is widespread among the population and those infected remain largely asymptomatic. This drug treats inflammation of the retina caused by CMV when the patient's immune system is weakened by HIV. So far Cidofovir has shown in vitro (outside of the body; petri dishes) activity against the BK virus; however, there are conflicting reports of in vivo activity. Cidofovir has so far been used to treat patients with both BK-related hemorrhagic cystitis and CMV infection. It was found to reduce both CMV replication and the level of BK viruria, and resulted in clinical improvement. Low dose Cidofovir treatment has been used in bone marrow transplants with positive clinical outcomes and decreased viruria and viremia in 84% and 47% of the patients respectively. There are, however, also reports claiming the deleterious effects of reduced renal function and increased viral load in Cidofovir-treated BKVAN patients. Cidofovir also has limited treatment potential in renal transplant patients due to its nephrotoxicity as well as its limited oral bioavailability. The variable and the conflicting results of Cidofovir treatment show the need for randomized clinical drug trials.
CMX001:
CMX001 is a slightly better alternative to Cidofovir in that it is orally delivered and has reduced nephrotoxicity. It is also able to inhibit BK Virus replication much more rapidly and with a longer-lasting effect. This compound was tested in renal transplant and BMT recipients but the results of this clinical study were not yet available at the time this review was written.
As a fun fact this compounds full name of all individual elements in this compound are
phosphoric acid; [[(S)-2-(4-amino-2-oxo-1(2H)-pyrimidinyl)-1-(hydroxymethyl) ethoxy]methyl]mono[3-(hexadecyloxy)propyl] ester; hexadecyloxypropyl cidofovir
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