Fermara

I was wondering if anyone has ever tried Fermara and gotten pregnant successfully? We have been TTC for almost 2 years now and have done 3 rounds of Clomid. My ob/gyn has agreed to one more round of 150mg but if that doesn't work I will be referred to a specialist. Last month I did 100mg and my progesterone only increased to 5 (needs to be over 12). I was thinking of asking her about trying me in Fermara. Thanks!