Hi @snoopyluv345 this paper is based on an observational study you probably have already read. Table 2 and Figure 2 in "Result" showed correlation between lower ctx and stable bmd.
https://www.sciencedirect.com/science/article/pii/S8756328223000972
In "Discussion", authors wrote, "An adequate response for the management of denosumab discontinuation is defined as “a level of sCTX below the mean found in healthy premenopausal women, with a threshold below 280 ng/l” [24]. Higher doses or higher frequency of BP administration than those used in the treatment of osteoporosis could be required. Recommending a standardized BP treatment would be ideal, but it may be necessary to adjust the dose and/or frequency of BP administration once the sCTX exceeds the indicated threshold".

You could check out their reference article #24 for their source of info.

Finding a right doctor who does not hesitate to do an off-label use of a pharmaceutical when necessary based on clinical experience is challenging.