If, by published you mean published in a peer-reviewed journal, then no. Studies are registered before they start, but clinical trials fail or are withdrawn for

If, by published you mean published in a peer-reviewed journal, then no. Studies are registered before they start, but clinical trials fail or are withdrawn for various reasons (like safety problems, lack of funding, etc). I imagine that registered studies that are completed are published if they have positive results, or negative results that contradict other well-known positive results. There's no reason not to publish if you get a good or interesting result. But publication can take years, so I don't think it's particularly unusual to see a completed study without a corresponding publication. But again, the specific cases you linked predate the current registration and reporting requirements.