The fiancée of jailed Egyptian-Canadian journalist Mohamed Fahmy says they will "fight until we get him out of this nightmare" after an appeals court ordered a retrial in the case on Thursday.

Fahmy and two of his colleagues from Al-Jazeera English -- Egyptian Baher Mohammed and Australian Peter Greste -- have been in an Egyptian prison since they were arrested in December 2013, amid what Fahmy's fiancée called a "cold war" between Egypt and Qatar.

Qatar owns Al-Jazeera, which Egyptian authorities have dubbed a mouthpiece for the Muslim Brotherhood, a hardline Islamist group that Egypt deemed a terror organization last April.

The network denies the accusations, and lawyers for the three journalists say the men were arrested for merely doing their jobs.

Marwa Omara, Fahmy's fiancée, said Thursday that although the appeal court's decision gives her reason to be optimistic, Fahmy and his family expected that he would be released on bail.

"It's a very sad day for me, for Mohamed’s family and definitely for Mohamed," Omara told CTV News Channel in a telephone interview from Cairo.

"I expected that they would release them on bail. They did nothing, and the whole world knows that they did nothing."

Fahmy is suffering from hepatitis C and shoulder pain, Omara said, adding that she also believes her fiancé is being physically tortured in jail.

"We're still optimistic and we’ll keep fighting until the end," Omara said. "I'm going to fight with Mohamed until we get him out of this nightmare."

The new trial should get underway within a month, Fahmy’s brother, Adel, said Thursday, and it should be shorter than the previous trial.

Many of the arguments made by the prosecution during the first trial were deemed invalid during the appeal hearing, he told News Channel, including the charge that anyone who works for Al-Jazeera is automatically a member of the Muslim Brotherhood, and the charge of being a member of a terror group.

Egypt only declared the Muslim Brotherhood a terror organization four months after Fahmy and his colleagues were arrested, Adel Fahmy said.

At trial, prosecutors did not present evidence backing their claims that the three journalists falsified news reports to foment unrest in Egypt. Prosecutors presented edited reports by the journalists about protests in Egypt, as well as footage from unrelated stories.

Thursday's decision, which was issued by Egypt's Court of Cassation after a brief morning hearing, nullifies everything that happened in the first trial, including the verdicts.

Fahmy and Greste had been sentenced to seven years in prison, while Mohammed received 10 years.

Following Thursday's ruling, Al-Jazeera issued a statement decrying the fact that the journalists "have been unjustly in jail for over a year now."

The statement went on: "The Egyptian authorities have a simple choice: free these men quickly or continue to string this out, all the while continuing this injustice and harming the image of their own country in the eyes of the world."

Adel Fahmy told reporters in Cairo that his brother and his colleagues "should not be caught in the middle of this remote conflict between two nations."

"They are the only ones paying the prices," he said. "They are being punished on behalf of Qatar and Al-Jazeera."

Foreign Affairs Minister John Baird is scheduled to travel to Egypt later this month, to press Fahmy's case.

On Thursday, Lynne Yelich, minister of state for foreign affairs, said the federal government "maintains serious concerns with the judicial process" that led to Fahmy’s previous conviction.

"We welcome this decision and anticipate the new judicial process involving Mr. Fahmy to be conducted in a fair, transparent, and expedited manner," the statement read.

Canadian officials continue to provide consular assistance, and are working with Egyptian authorities to ensure Fahmy's health issues are treated.

Meanwhile, Omara fears that her fiance's retrial could drag on for a year.

She says Fahmy's lawyers, including noted human-rights attorney Amal Clooney, have submitted a request to the prosecution that Fahmy be deported to Canada.

Under a new law, Egyptian President Abdel-Fattah el-Sissi can pardon or depart foreigners who have been convicted in Egyptian courts.

Fahmy could return to Canada, so long as he gives up his Egyptian citizenship.

"This is our last hope, because Mohamed's health is deteriorating," Omara said.

With files from The Associated Press and The Canadian Press