In vim, it would probably have to be done in two separate commands

    # Search and replace using a 2-variable regex
    :275,1305s/two_variable_regex/first\1second\2/g

    # Replace TEST_ with test_
    :275,1305g!/a_regex/s/TEST_/test_/g

But, if it's too convoluted to do something like this in vim, you can instead do something like:

    :275,1305 !perl -ne '# substitution, then print'