Hi Peter,
Good to see a new contributor. As more of us contribute, the more members will get involved and be able to support and help each other learn about amyloidosis.
There are several people, myself included, who have problems with their legs much as you have described. There are several topics discussing this e.g. Neuropathy and Dry Mouth.
As for your question, I wish I knew the answer. There is a new drug, the Anti-SAP Antibody drug, which is on clinical trial at the moment. See the link to a presentation on it in Pat's post in the Dry Mouth topic. It's looking promising so far, but it's a long process to get it approved. However, hopefully it will provide us with the answer.