Treating prostitutes as victims rather than criminals after the murders of five women has helped almost eradicate the issue in Ipswich, a report said.
Steve Wright's killing spree in 2006 sparked an operation by police and other agencies to tackle the problem.
An evaluation of the scheme, which was heralded a success two years ago, said a new approach to prostitution had helped change women's lives.
But it said more work was needed for the policy to be a long-term success.
The findings, based over five years, were presented by independent experts at the University of East Anglia.
They said high intensity police patrolling, CCTV and a zero-tolerance to kerb crawling had led to an almost complete disappearance of street prostitution in the town.
Identifying routes out of prostitution and preventing vulnerable people from getting into the sex trade had also been a success, with nearly 300 young people being recently helped, they added.
Providing suitable accommodation for women and helping them kick their drug habits were some of the areas identified as being effective.
Prof Fiona Poland, who specialises in social research methodology, said: "You can't say the project will have brought about a 100% change.
"It halved the [criminal justice] costs, it reduced arrests by three quarters. Of the women we worked with they were generally in insecure housing situations - they were all found housing, so there were many, many ways in which the project worked.
"We're bringing together people from the voluntary sector, the council, criminal justice agencies and health and social services to look at how that multi-agency working can be sustained in the longer term."
Five women who worked in the sex industry in Ipswich were murdered after disappearing over a six-week period in 2006.