Partially-paralysed broadcaster Andrew Marr said a new drug he flew to the US for had not resulted in the "dramatic" change he hoped for.
The treatment, described by Marr as a "Christmas present" to himself, involved hanging upside down while having Etanercept, an anti-inflammatory drug, injected into his spinal fluid.
He said he will now work to build on the small changes he has seen.
Marr, who suffered a stroke in 2013, said: "Although I haven't seen the dramatic improvements that I hoped for, there have been subtle and useful changes which I am going to work on through physiotherapy and exercise over the coming months.
"It hasn't been 'pick up thy bed and walk' but it hasn't been nothing, either.
"We will tell the fuller story in a BBC documentary scheduled to be broadcast in January."
Marr's stroke left him spending two months in hospital and undergoing extensive physiotherapy to help him walk. He remains semi-paralysed on his left side.
In a piece for the Spectator recently, he wrote: "I'm not complaining too much: I can work, drink, see friends, paint, listen to music and irritate my children like before. I'm a lucky fellow.
"But I can't run or cycle or swim, and I walk very unsteadily and slowly. I drop things and take ages to get dressed."