Battles continued between government forces and the jihadist group in the area in the southeast of Aleppo province, the Britain-based Syrian Observatory for Human Rights said, Reuters reported.
Government forces had been relying on the route to reach Aleppo because insurgents control the main highway to the city further west.
Islamic State seized the town of Khanaser, which lies on the route 50 km (30 miles) southeast of Aleppo city, last week but government forces regained it two days later.
State TV said on Monday further advances allowed government forces to regain control of the road and they were now clearing mines.
The government advances in Aleppo province, helped by Russian air strikes and allied fighters from Iran and Lebanese Hezbollah, come on the third day of a country-wide cessation of hostilities that excludes Islamic State and al Qaeda affiliate Nusra Front.