April 27 (Reuters) - Following are the top stories in the Wall Street Journal. Reuters has not verified these stories and does not vouch for their accuracy.
* Rescuers in Nepal struggled to reach remote areas hit by Nepal's most devastating earthquake in roughly 80 years. (on.wsj.com/1IdhbEU)
* President Barack Obama tightened rules for the U.S. drone program in 2013, but secretly approved a waiver giving the Central Intelligence Agency more flexibility in Pakistan than anywhere else to strike suspected militants, according to current and former U.S. officials. (on.wsj.com/1IdhbVm)
* With Ferdinand Piech's departure Saturday, Volkswagen AG faces two weeks of uncertainty before its annual meeting on May 5, as the automotive giant faces big challenges getting back in gear amid slumping sales in the U.S. and China and high costs in Europe. (on.wsj.com/1GyyIIk)
* Investigators overlooked evidence given to them just hours after the 2010 "flash crash" that could have enabled them to uncover the strategies of Navinder Sarao, the trader now accused of helping cause the violent selloff in stocks that day, according to members of a committee that oversaw the investigation. (on.wsj.com/1IdhC2a)
* Pharmaceutical companies such as Valeant are buying drugs that they see as undervalued, then raising their prices.(on.wsj.com/1IdhEqH)
* The world's largest advertiser, Procter & Gamble Co , plans deep cuts in the number of ad agencies it works with in hopes of big savings on fees.(on.wsj.com/1IdhMXd) (Compiled by Ismail Shakil in Bengaluru)