Miss McIntyre, Conservative MEP for the West Midlands, is still hoping she and a group of parliamentary colleagues can win a stay of execution and a retrial for Mohammad Salas.
The Iranian authorities have spurned all previous appeals for the withdrawal of a death sentence on Mr Salas and have said he will be executed after the Muslim holy month of Ramadan, which ends this weekend.
Supporters say Mr Salas, a Gonabi Dervish, was wrongly convicted of the murder of three police officers when the case against him remained incomplete and unsubstantiated. Eyewitness and photographic evidence establishing his innocence was ignored by the court, while an alleged confession was extracted under duress.
He was sentenced to death by the Iranian Supreme Court in April.
With possibly only hours to go before the sentence is implemented, Miss McIntyre has circulated a letter making a final plea to Tehran to halt the execution.
It has already been signed by 47 MEPs from 19 Member States and six political groups.