The link to the NIH survey was the one I gave you previously and you indicated you already had that essay.

The following is quoted from a portion of that publication , summarizing what various countries are recommending. It is the last sentence that provide BTM targets for 'an adequate response'

"The European Calcified Tissue Society (ECTS) provided the most updated guidance on the issue. Guidance for denosumab discontinuation is stratified according to the duration of use and individual fracture risk [39]. Individuals with high fracture risk treated with denosumab for more than 2.5 years should continue denosumab for up to 10 years or alternatively switch to zoledronic acid starting 6 months after the last denosumab injection and monitor BTMs 3 and 6 months later, and a repeat dose should be considered if BTMs are persistently elevated. Alternatively, zoledronic acid should be given at 6 and 12 months after the last denosumab injection if BTMs are not available. Oral bisphosphonates for 12 to 24 months can be used in place of zoledronic acid. Conversely, individuals with low fracture risk treated with denosumab for less than 2.5 years may be switched to 1 to 2 years of oral bisphosphonates or zoledronic acid with close monitoring of BTMs and BMD. BTM targets of CTX < 280 ng/L or P1NP < 35 µg/L were specified as targets for an adequate response."

Hope you find this helpful.