How to open a Catia drawing with VB.NET

I'm trying to open a CATIA Drawing file with VB.NET (I'm using Visual Studio 2019) in order to edit some parameters, eventhough the file does open successfully the code block right on the opening line.

Error message pops-up at this line: (the file still opens successfully)

drawingDoc1 = doc1.Open("E:\TEMP\Drawings\D18-050022707.CATDrawing")

Error message:

System.InvalidCastException: 'Unable to cast COM object of type 'System.__ComObject' to interface type 'MECMOD.PartDocument'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{818C8B33-806B-0000-0280-030D3B000000}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).

The code works for opening a CATPart but not CATDrawing or CATProduct, so my guess is the interface "MECMOD.Part" can be used only for CATPart, but what should be the interface for CATDrawing or CATProduct ?

I have added all CATIA references.

        Dim CATIA As INFITF.Application

        Try
            CATIA = GetObject(, "CATIA.Application")
        Catch
            CATIA = CreateObject("CATIA.Application")
        End Try

        CATIA.Visible = True
        CATIA.DisplayFileAlerts = True

        Dim doc1 As INFITF.Documents
        doc1 = CATIA.Documents

        Dim drawingDoc1 As MECMOD.PartDocument
        CATIA.DisplayFileAlerts = False

        drawingDoc1 = doc1.Open("E:\TEMP\Drawings\D18-050022707.CATDrawing")