“Aren’t the Iranians involved here?”
The Iranians played a big military role, and took some heavy casualties, including several of their senior officers. It was their bloodiest engagement since the Iran/Iraq War in the 1980’s. Since the situation has stabilized, and Assad is no longer on the brink of defeat, the Iranians have redeployed most of their combat forces back home, or pulled them off the lines for rear security.
Iranian advisors still pretty much run the Shi’ite militias though.
Summer of 2015 was probably the worst part of the war for Assad. The rebels were getting real close to Assad’s homeland in Latakia, the home of Assad’s tribe known as the Alawites.