Is there a closed form expression for $\mathbb{P}[X\leq np]$, $X \sim $ Bin$(n,p)$?

Question

Let $X \sim $ Bin$(n,p)$ be a binomial random variable. Does anyone know a way to simplify $\mathbb{P}[X\leq np] = \sum_{i=0}^{np}\binom{n}{i}p^i(1-p)^{n-i}$ (i.e. the probability that $X$ is not greater than the mean value)? Any help appreciated!