A 20-year-old man was found with serious injuries at the junction with Church Street and Avenham Street, close to the Co-Op bank at around 2.40am on February 16.
The victim, from Preston, had suffered several cuts, facial fractures and bleeds on the brain in the assault.
He was taken to hospital for treatment and surgery, with his current condition described as critical.
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Two other men, aged 19 and 20, were also attacked during the incident, suffering minor injuries.
Temp Det Sgt Richard Shires, of Preston CID, said: “We are appealing to any witnesses to come forward with information.
“While we have made a number of arrests, the victim remains in a coma and is currently in a critical condition at hospital.
“I would ask anyone with information, no matter how seemingly insignificant, to come forward and speak to police.
“A man is fighting for his life and we need to find those responsible.
“If you saw what happened please come forward immediately and speak to us.”
Following extensive enquiries seven men, aged 19 and 31, from Blackburn, were arrested by police on suspicion of assault.
They were later released under investigation.
Detectives are urging any witnesses to come forward.
Anyone with information can contact police on (01772) 209803 or email [email protected] quoting log reference number 0178 of February 16.
Alternatively, independent charity Crimestoppers can be contacted anonymously on 0800 555 111.