High Court judges have refused permission for the case of Melksham locked-in syndrome sufferer Tony Nicklinson, who died shortly after losing a landmark right-to-die legal battle, to go to the Court of Appeal.
But they allowed a second sufferer of the syndrome, who also lost his case at the High Court in August, to have his action against the Director of Public Prosecutions heard by appeal judges.
The parties were informed of the appeal decisions made by Lord Justice Toulson, Mr Justice Royce and Mrs Justice Macur, in a written ruling sent to them today.
Stroke victim Mr Nicklinson, a 58-year-old married father-of-two, died a week after he lost his court fight to end his life when he chose with a doctor's help.
He had been refusing food and contracted pneumonia, dying surrounded by his family on August 22.
His wife Jane vowed to carry on the case.
The judges said they were "deeply conscious of her suffering" since Mr Nicklinson's stroke, but said they did "not consider that the proposed appeal has any real prospect of success".
They turned down an application by Mrs Nicklinson to be made a party to the proceedings.
Giving the ruling of the court, Lord Justice Toulson said: "It is, of course, an important question whether the law of murder should be changed in the way that Tony fought for, but it does not follow that permission to appeal should therefore be granted.
"We consider it to be plainly a matter for Parliament."
The second sufferer, who cannot be named for legal reasons, but is known as AM or Martin, suffered a massive stroke in August 2008.
He is unable to speak, is virtually unable to move and describes his life as "undignified, distressing and intolerable" - he wants to be allowed a "dignified suicide".
His lawyers said the High Court ruling deprived 47-year-old Martin of "the opportunity to take the necessary steps to end his own life".
Mrs Nicklinson said she was unable to comment on the ruling until she had received a copy of it and spoken to her lawyer.