i've been on C for 9 yrs and i'm stable.
it doesn't sound like your dh is tho. changing meds seems a reasonable idea.
i agree with all the advice you've gotten. do some research. decide on which of the interferons you might want to try.

getting new lesions is a good reason to switch meds.
it's not a cure but may keep the progression at bay.

i also agree that getting a 2nd opinion is a good option.
you may also want to call shared solution and ask them about this situation.
why the C isn't working. i know they'll be slanted towards their own med but
you also might learn something.

please let us know how your dh is and what you decide.