The family of late locked-in syndrome sufferer Tony Nicklinson and paralysed road accident victim Paul Lamb have lost their right-to-die challenges.
The Court of Appeal upheld a ruling that Mr Nicklinson had not had the right to ask a doctor to end his life. His widow is planning a further appeal.
Mr Lamb who won a battle to join the Nicklinson case also plans to appeal.
But a third paralysed man won his case seeking clearer prosecution guidance for health workers who help others die.
The man, known only as Martin, wants it to be lawful for a doctor or nurse to help him travel abroad to die with the help of a suicide organisation in Switzerland. His wife and other family want no involvement in his suicide.
The director of public prosecutions, who would be required to clarify his guidance, is seeking to appeal to the Supreme Court against the decision in Martin's case.
Speaking by means of special computer software, Martin said he was "delighted" by the judgement.
"It takes me one step closer to being able to decide how and when I end my life. I am only unable to take my own life because of my physical disabilities.
"Almost every aspect of my daily life is outside of my control. I want, at least, to be able to control my death and this judgement goes some way to allow me to do this."
'Conscience of the nation'
In the Nicklinson and Lamb case, the decision centred on whether the High Court was right in originally ruling that Parliament, not judges should decide whether the law on assisted dying should change.
The three Court of Appeal judges unanimously dismissed Mrs Nicklinson and Paul Lamb's challenge.
In the judgement, the Lord Chief Justice Lord Judge said Parliament represented "the conscience of the nation" when it came to addressing life and death issues, such as abortions and the death penalty.
Paul Lamb: "It's unfair and I think it's cruel"
"Judges, however eminent, do not: our responsibility is to discover the relevant legal principles, and apply the law as we find it."
Mr Nicklinson was 58 when he died naturally at his home in Wiltshire last year. His widow Jane, who has continued his fight, told the BBC she was "very, very disappointed" by the ruling, but "not totally surprised".
She added: "We will carry on with the case for as long as we can so that others who find themselves in a position similar to Tony don't have to suffer as he did. Nobody deserves such cruelty.
"Although we lost, the legal team are quite pleased with the outcome - the appeal judges actually upheld a couple of points which the High Court rejected, which is a step forward."
Paul Lamb wanted the law changed so any doctor who helped him die would have a defence against the charge of murder.
The 57-year-old from Leeds has been almost completely paralysed from the neck down since a car accident 23 years ago and says he is in constant pain.
"I was hoping for a humane and dignified end - this judgement does not give me that," he said.
"I will carry on the legal fight - this is not just about me but about many, many other people who are being denied the right to die a humane and dignified death just because the law is too scared to grapple with these issues."
Saimo Chahal, the solicitor acting for Mrs Nicklinson and Mr Lamb, said there was "no prospect of Parliament adjudicating on the issue any time soon" so Paul's only option was to try to persuade the courts that his concerns were "real and legitimate".
But Dr Andrew Fergusson, of the Care Not Killing campaign group, welcomed the Nicklinson and Lamb ruling, saying: "All three judges were very clear on legal, and I think ethical, grounds as well, that the law, if it's to be changed, must be changed by parliament alone. The courts cannot do it."
The British Humanist Association, which has supported Mr Lamb's case, described the matter as the "most important bioethical issue of our time".
It said it should not fall to people who have "already suffered enough" to fight legal case after legal case. Instead, Parliament and government should be putting the work in on changing the law.
Sarah Wootton, of the Dignity in Dying campaign, urged for some parliamentary debate and for MPs to look at the private members' bill tabled by Lord Falconer for the legalisation of assisted suicide for the terminally ill in England and Wales.