Replies to post #3881 on PROTALIX BIOTHERAPEUTICS, INC. (PLX)

[Spideyboy]

I would disagree that the once per 4 week is very important for the market potential of Elfabrio, when compared to the equal efficacy and better safety, and probable real world better efficacy.

I think for this it is important to define the 'doing well on Fabrazyme'. Let us remember that from the clinical data, Fabrazyme causes ADAs/immunogenic response in 74% of patients.

So if we assume that doing well on Fabrazyme is in that 26% of patients, then yes, that person would be best suited to switch on to the once per 4 month dosing if/when available.

But the other 74%, even if doing well on the efficacy of Fabrazyme and generally well on more important side effects will still not be feeling great due to this ADA positive activity in their system.

Whereas in the Balance trial, patients with ADA's dropped when on Elfabrio, by 34% and dropped the neutralising antibodies by 55%.

And this is in patients who had already been on Fabrazyme for a mean of 6 years, so these are patients that are tolerating Fabrazyme well/or at least much better than others (clinical trial was in USA and 11 countries outside the USA).

So I think this type of patient (in the 74% ADA) doing well on Fabrazyme, would still be better off on Elfabrio. And this type of patient would already be accustomed to the once per 2 week regimen over many years of Fabrazyme, so it's not like Elfabrio is a detractor on that.

Thus for this type of patient in the 74% with ADAs would be a candidate for Elfabrio. Anyone doing well on efficacy and no adverse reaction and no ADAs would be fine to stay on Fabrazyme.

As remember in the Balance study, TEAE in total were 4x higher for Fabrazyme, and Infusion-Related-Reactions number and rate were 4x and 8x higher respectively for Fabrazyme.