Retrieve a single value from an array

Question

I'm using CURL to request a payload from an API. I've decoded my JSON result into an associative array

$arr = json_decode($result, true);

Results of print_r($arr);:

Array (
    [total] => 55
    [values] => Array (
        [0] => 200
        [1] => HEALTH-1628204836-435
        [2] => Success
        [3] => TYKERB TAB 250MG
        [4] => TYKERB
        [5] => LAPATINIB DITOSYLATE TAB 250 MG (BASE EQUIV)
        [6] => 03
        [7] => 00078067119
        [8] => 250.00000
        [9] => MG
        [10] => TABS
        [11] => Tablet
    )
)

How do I retrieve [4] TYKERB from this array?