Is this use of the word “concomitant” natural? What other words can be used?

Question

From a clinical trial synopsis (Boehringer Ingelheim 1239.1):

Dose: Starting dose of 150 mg b.i.d. (twice daily) BIBF 1120, followed by dose escalation of 50 mg for successive cohorts, up to a maximum of 250 mg b.i.d. (concomitant with BIBW 2992)

BIBF 1120 and BIBW 2992 are names of drugs. Is the word "concomitant" felicitous here, or is it better to use simultaneously with? What other naturally-sounding alternatives could there be?

I thought that we use "concomitant" when something happens by itself, but here the study authors chose to use this combination of drugs.

Answer 1

concomitant

has a specific clinical meaning which goes beyond "simultaneously", it means two things have a relationship with each other, it can be used for application as well as observed related side-effects.

In your example BIBF 1120 and BIBW 2992 are both kinase inhibitors and so both are meant to be applied together (interrelated) in order to shutdown that biological pathway necessary for angiogenesis.

Answer 2

If you just want to mean simultaneously with, and there are no other connections between BIBF 1120 and BIBW 2992, concomitant is not the right word.

The Cambridge dictionary provides this definition of Concomitant: note the words that I have highlighted.

something that happens with something else and is connected with it

So, while it is legitimate to say

dementia is concomitant with old age

It is not OK to say

We drank the wine concomitantly with dinner

... unless you really believe that there could be no dinner without wine :-)