John Gravell, 51, who needs a transplant within six weeks, had hoped that he could be given bone marrow from his brother Barry, after matches had failed with other donors. There was only a one in four chance Barry would be a suitable donor.
Until last Wednesday, the two men had not seen each other since the Seventies when Barry, now 49, walked out in an argument with other family members. But he responded to appeals in newspapers and on television after doctors told John he had just months to live.
John Gravell was diagnosed with acute myeloid leukaemia in May and underwent chemotherapy, which was unsuccessful. Doctors failed to match the former company director with any other donor, including his children and sister.
Dr Mike Hutchinson, Mr Gravell's consultant, said he was extremely disappointed at the results, but there was a chance another unrelated donor might be suitable. "Obviously this is very disappointing news for John and his family and he has asked me to thank all the media on his behalf for their enthusiasm and help in tracing his brother."
The consultant said Mr Gravell had two options. He could continue with chemotherapy, though this would give him only a 20 per cent chance of survival after five years or, alternatively, he could have a bone marrow transplant with another matching donor who had been found - which offered a 40 per cent chance.