[Grammar] to produce or to be producing? -> infinitive passive

[GusiaPL]

The original sentence is: It was claimed that the drug produced no undesirable side - effects.
I'm trying to do a passive voice sentence and I wonder if it should be 'The drug was claimed to be producing no undesirable side - effects' or 'The drug was claimed to produce no undesirable side - effects'
In the textbook I use there are examples only with the verb 'be' and I'm not sure what to do with other verbs... :-?

 

[Raymott]

The first clause is already passive.
"It was claimed that no undesirable side-effects were produced by the drug."