Per Bulkoswski's Encyclopedia of Chart Patterns, throwbacks occur 74% of the time.
Maybe waiting for the throwback to bounce off of this trendline (top of the handle formation) to confirm a breakout.
The price target might not be that dependable, but an overall 26% failure rate on this cup and handle (10% if confirmation is made with by waiting for a breakout, after throwback) formation, are good odds for a trade. Consider a trailing stop if your market has sufficient liquidity. Otherwise place your stop below the handle to allow for a return to the bottom of the pennant/handle.