There are lots of drugs available for the treatment of Hemophilia A.  .

Recombinant factor VIII as well as purified plasma preps are pretty common.  In the last few years several modified FVIII compounds have been produced and are in the process of FDA approval that have half-lives significantly longer than the (very) labile native FVIII protein.

As for bypassing the coagulation cascade, if you were to overload a patient with too much FVIII the patient would be at elevated risk for thrombosis.  And, as I mentioned, FVIII is very labile with a half-life of several hours (patients with several Hem A require multiple factor replacement infusions a week for effective prophylaxis).

That said, there is very exciting research coming out of a few labs that are using adeno associated virus to reprogram patient livers to produce active FVIII.  An early clinical trial presented at the ISTH meeting in July showed sustained (months) expression of 30-80% of 'normal' following injections of viral particles.  As a barometer, prophylaxis factor replacement seeks to achieve 5-10% at peak levels.

There is even better results for Hemophilia B patients using a similar approach.

I agree with Matthew. There are several very effective treatments available for haemophilia. I suspect Shristi doesn't consider replacement proteins as 'drugs'

As to Matthew's comments about gene therapy for haemophilia, I wouldn't get too excited about this. There has been enormous hype about this subject over the last 25 years. Unfortunately we are still hyping but haven't seen any major advance that has been translated into a discernible clinical benefit. I suppose we all can live in hope.

Siva

Thank you for the answers. Dr. Sivakumaran, ofcourse replacement options are the reason haemophiliacs are suffering a little less, no denying their importance, I was just curious about chemical drugs rather than their biological counterparts.