While there's nothing definite saying there aren't going to be any more Enterprise
novels, it doesn't look too promising either. So, at the Expanse, we decided to mobilize and let TPTB know that we love the books and we want more. Rather than go into it all here, the above link has all the information of what we're doing, who to send letters to, etc.
Also, if you have a Twitter account, we're encouraging people to tweet about the novels using the #startrekenterprise and #startrekprofic hashtags.