#!/bin/bash
s="&VAR1 =  '1111' and more &VAR1=1111 here"
echo "${s}" | sed "s/&VAR1[[:blank:]]*=[[:blank:]]*'\?1\{4\}'\?/EXAMPLE/g"
echo "${s}" | sed "s/&VAR1\s*=\s*'\?1\{4\}'\?/EXAMPLE/g"
echo "${s}" | sed "s/&VAR1[[:blank:]]*=[[:blank:]]*'\{0,\}1\{4\}'\{0,\}/EXAMPLE/g"
echo "${s}" | sed -E "s/&VAR1[[:blank:]]*=[[:blank:]]*'?1{4}'?/EXAMPLE/g"