In letters sent by Elijah E Cummings (Ranking Member of the House Committee on Oversight and Government Reform), and Senator Bernard Sanders, 14 companies have been asked to share "information about the escalating prices they have been charging for generic drugs".
Cummings and Sanders are investigating price increases for drugs used to treat everything from common medical conditions to life-threatening illnesses and to identify measures to help reduce costs for patients, healthcare providers, and hospitals across the country (US), said a statement on the US House of Representatives website.
In their letters, Cummings and Sanders cited data from the Healthcare Supply Chain Association on recent purchases of 10 generic drugs by group purchasing organisations over the past two years.
"When you see how much the prices of these drugs have increased just over the past year, it's staggering, and we want to know why," said Cummings.
"In some cases these outrageous price hikes are preventing patients from getting the drugs they need," he added.
The Members asked the companies to provide information from 2012 to the present, including total gross revenues from sales of the drugs, prices paid for the drugs, factors that contributed to decisions to increase prices, and the identity of company officials responsible for setting drug prices.
Commenting on the price rise of the generic medicines, Sanders, who is Chairman of the Subcommittee on Primary Health and Aging, Senate Committee on Health, Education, Labor and Pensions said: "Generic drugs were meant to help make medications affordable for the millions of Americans who rely on prescriptions to manage their health needs. We've got to get to the bottom of these enormous price increases."
When contacted, a Dr Reddy's spokesperson said: "The company is in the process of responding to the notice and is confident of addressing these queries successfully. It did not initiate any price increasing activity for the products mentioned in the notice."
Sun Pharma spokesperson declined to comment.
The other companies which have been asked to share information are Actavis, Apotex Corp, Endo International, Global Pharmaceuticals, Heritage Pharmaceuticals, Lannett Company, Marathon Pharmaceuticals, Mylan, PAR Pharmaceutical, Teva, West-Ward Pharmaceutical and Zydus Pharmaceuticals.
The share prices of Dr Reddy's and Sun Pharma dropped by 4.37 per cent to Rs 2,963.65 per scrip and 4.31 per cent to Rs 800.75 per share respectively on close of day's trade on the BSE. .