Gilead Sciences successfully surpassed the expectations of Wall Street as the sales of its drugs to treat hepatitis C reached $4.55 billion in the first quarter. Gilead's new drug, Harvoni, which was approved in last October, had overall sales of $3.58 billion in this quarter.

But the sales of its older hepatitis C drug, Sovaldi has decreased as it was supplemented by Harvoni. The overall sale of Sovaldi fell to $972 million in this quarter from $2.27 billion in the first quarter of 2014.

However, calculated together, the hepatitis C drug sale in the first quarter was doubled than what it was a year earlier. The escalation in the sales of the hepatitis C drugs has given Gilead a competitive edge. It has made Gilead one of the top earners in the pharmaceutical industry with its profits exceeding that of older and bigger rivals like Viekira Pak from AbbVie.

On Thursday, the company optimistically announced that it expected $28 billion to $29 billion this year from its total product sales, inclusive of drugs for hepatitis C, HIV and other diseases. In February, the company had projected sale of $26 billion to $27 billion.

Nonetheless, it is required to focus attention on the overall costs to the health care system because of these medicines. A singe pill of Gilead's hepatitis C drugs costs a whopping $1,000 or more. The high costs have strained the budgets of various insurers, state Medicaid programs and prison systems, thus leading them to be restrictive on the number of patients which can be treated.

As a retaliatory measure, several bills have been introduced in at least five state legislatures that would require companies to disclose their costs for developing expensive drugs. The pharmaceutical industry is opposing all such legislations.