No, you don't need to do meta-analysis. Without combining the results of multiple trials together, you can see if an observed effect in one trial is found in other trials through independent analysis.
But explaining whether or not "We didn't get the same answer" is the result of variation in the effect estimate, or because of a genuine failure to replicate, is one aspect of meta-analysis.
The purpose of meta-analysis goes beyond pooling. Indeed, one of the first steps in meta-analysis is "Is pooling even a good idea?"
