Be aware that the filling needle is a very important area to clean. It is understood that it is a smaller area, but since it is closer to the final fill, a contaminated needle could potentially drop any/all contamination in one single unit. A contamination on the fill needle could result in a higher concentrated contamination compared to a process tank upstream, where a contamination would be diluted throughout the whole bulk.
So not all sites are considered equal, and a filling needle would be considered highest risk location.
A cleaning validation might not be required, but you might want to have a “risk assessment” paper detailing why cleaning validation is not required. In this risk assessment you should discuss the dedicated needle/product line, and also any cleaning method, cleaning agents/chemicals, hold times, etc. You could also discuss possibility for microbial contamination. You might want to clean the needle immediately after use to get the material oof, then somehow sanitize prior to use using autoclave, or other methods to be doubly sure there is no microbial contamination. For a sterile filler operation, the autoclave should take care of everything. Also, microbial control would be supported using a media fill process simulation (if applicable).
There are a few other things to consider - such as removal of cleaning detergent (if applicable). But this should help get you started.