Filter / Summarize Table by Max Value index

Hi All,

I have one table with duplicated rows. I would like to remove these duplicates. It can be achieved by using one column and keeping the highest index. Here is a simple example. For each period and each item, I would like to have only 1 row. 

I have tried this formula:

_MyTable2 = 
var _maxindex = CALCULATE ( MAXX (Table_test,  Table_test[category_index] ) , ALLEXCEPT ( Table_test, Table_test[item] ) )
RETURN 
FILTER (Table_test, Table_test[category_index] = _maxindex )

In January, I have 2 rows for item A and I would like to keep only the one with the max index (=2)

In January, I have 1 row for item B and I want to keep it. My formula works.

However, in February I should have 1 row for each item with same logic. In that case, the row with the item A is not retreived, just like if the index of A (1) is compared with the index of B (2). Please see the 2 tables below (initial and expected). I hope you can help me solve this. Thanks in advance.

The initial table :

And the expected output: