Sorry about the small fiber neuropathy. I don't have the experience myself with transitioning from Humira to Cosentyx. However, in a few years I might be in your shoes needing to transition to Cosentyx.
The mechanism of action of the two drugs are different. Humira reduces the cytokine TNF-alpha while Cosentyx reduces the cytokine IL-17. So the two drugs interact with your immune system in different ways.
The way I understand it, there is really no way to know (with the present state of DNA research and medicine) whether TNF-alpha or IL-17 inhibition will work better in a particular patient. Most studies that came out this far seem to indicate that the effects of the two drugs are comparable with spondylitis patients at large
Perhaps some studies point to less axial joint damage (long term) with Cosentyx, in addition to a small increased chance of reaching remission or near-remission results.
Background: 31 yr old male
Symptoms: Ps (scalp, elbows, knees) since 2000; PsSpa (neck, sacroiliac joint) since 2015
Dx: Osteoarthritis Aug, 2017; PsSpa Nov, 2018
Treatment: Meloxicam, Nov 2018-Jan 2019; Naproxen, Jan 2019-Jun 2019; Humira, Jun 2019-Present