The Cure Graph shows you the status of the cure.
It displays two values charted over time, the Cure requirement and the Research conducted. Both are measured in terms of millions of dollars. When the research conducted reaches the cure requirement, the cure will be ready.
Even if the cure has reached 100%, it is still possible to reverse it and make the cure ineffective, forcing the scientists to have to continue working on the cure. This is done by acquiring the ability Genetic Reshuffle, which increases the cure requirement, even after the cure has been deployed; due to the way the game works, if Cure Requirement > Cure Conducted, the cure cannot work, even if it has already reached 100%. This effectively halts the cure, temporarily.