If the spike's at the end of its blooming cycle, I would go ahead and cut it--maybe an inch or two from the base of the pseudobulb that produced it. Be careful that you don't accidentally cut any new growths that the bulb might be producing; they usually grow close to the spikes and it's very easy--with all of those tall grassy leaves in the way--to make a wrong snip.
Sorry I took so long to respond. The spike is dry down into the green stuff so I'm going to cut it as you suggest. I now have three other spikes flowering. I feel lucky.