Merck & Co said that once a day use of its HIV drug Isentress had a lesser effect in late-stage HIV than a dosage of twice a day in a study done among patients who had not been previously treated for the AIDS-causing virus.

Basing on initial result, which caused dismay among many, Merck & Co drug manufacturing company said that the Phase III study will soon be put to end. The Phase III study could have given ways to a wider use of the HIV drug among people who have not been treated before.

The said product, which is the only one of its kind that is able to block integrase, is approved to be used with other HIV medicines by patients who have undergone treatment before, as well as those who have not been treated yet. Integrase, for the benefit of many, is an enzyme that allows the HIV virus to insert its genetic material into the human DNA.

Chris Schott, an analyst of J.P. Morgan, said in one of the research notes that the approved once a day usage of the drug may work in favor of the company. This could have increased the number of Isentress users in the long run. Schott believes that the news that has been brought out today will not cause a negative effect for and Merck & Co.

In an early afternoon trading on the New York Stock Exchange, the shares of Merck went down to 1.4 percent at $34.36 in the midst of turn downs in the stock market.Merck’s says that Insentress is recently their fastest-growing medicine. The sales went for as high as $278 million, or an increase of 41 percent. This puts Insentress to making earnings of $1 billion every year.

Schott stuck to his prediction that the annual sales of Isentress by 2015 would go for as high as $2 billion. However, he admits that the sales could have been more if the trial did not fail.

On the said study of 775 patients, a group was given 800 milligrams of Isentress once every day. The drug was administered along with other treatments for HIV. The other group received 400-milligram Isentress twice daily, which is the approved dosage, together with other standard HIV treatments.

In a time period of 48 weeks, patients who received the once a day treatment showed undetectable HIV levels among 83.2 percent of the patients. The other group, which they first thought would get a lower rate, showed an improvement on 88.9 percent of the patients.