Learn English – Meaning using *if it had been* and *if it was*

She had been treated with these medicine in 2004 - (correct) It's in past participle tense. It means in the past the action occurred over a specified amount of time.

She had being treated with these medicine in 2004 - (Incorrect) We say "She is/was being treated...."

And as for your last two examples they are also incorrect. You need to omit "as"

She said she had earlier been treated by the Guptas, in May 2003 (correct)

Both sets of sentences are correct, the difference between them is the meaning.

Now this difference is a little hard to explain, but I will do my best.

The verb 'to have' conjugates in the present as 'have' or 'has':

• I, you, we, they, you all = Have
• he, she, it = Has

In the past, it conjugates as 'had' for everyone.

Now when it comes to questions starting with 'to have', asking if someone has done something, they are asking about one of two situations, each with it's own meaning.

When you use 'had' (past tense), then you are asking about any time up to a specific moment in the past.

Had you run a marathon?

Meaning "At any time up until that moment in the past, did you run a marathon?", or "Did you run a marathon by then?"

When you use 'have' or 'have', you're asking about any moment up until right now.

Have you run a marathon?

Meaning "At any time up until now, did you run a marathon?", or "Did you run a marathon by now?"

The difference between the two is the limit of the time asked about. When you ask using the past tense of 'to have', then the limit is referring to a specific moment in the past. When you ask using the present tense of 'to have', then the limit is this very moment, now.

• Have, has = "up until now"
• Had = "up until then"

I hope that helps!