The court in Smolensk on February 15 sent Taisia Osipova's case for additional investigation. She is to remain in detention while the probe is carried out.
Osipova, a member of the opposition movement Other Russia, was jailed in December for drug possession after police said they found five packets containing drugs in her apartment.
Osipova's lawyers and supporters claimed the drugs were planted by police and that the case was fabricated in order to put pressure on her husband, Sergei Fomchenkov, a leading member of Other Russia.
The high-profile case prompted protests in Smolensk and Moscow and was raised by students of Moscow State University’s journalism department during a meeting with President Dmitry Medvedev last month.
Medvedev said he was ready to study Osipova's case and look into a possible pardon.
Osipova's name was also on a recent list of 39 jailed Russians considered political prisoners by opposition groups.
The groups drew up the list and sent it to the presidential office in response to Prime Minister Vladimir Putin's statement earlier this month that "there are no political prisoners in Russia."
Fomchenkov told RFE/RL that the February 15 court decision showed that his wife is not guilty. He said the prosecutor at the appeal trial asked the judge to shorten Osipova’s prison term from 10 to four years.
Fomchenkov linked the February 15 ruling with the upcoming presidential election scheduled for March 4.