Original sentence: A placebo-controlled randomized trial of AZT was subsequently conducted by Burroughs-Wellcome, in which it was shown that AZT could prolong the life of patients with AIDS.AZT does not destroy the HIV infection, but only delays the progression of the disease and the replication of virus, even at very high doses.During prolonged AZT treatment HIV has the ability to gain an increased resistance to AZT by mutation of the reverse transcriptase.It was originally intended to treat cancer, but failed to show efficacy and had an unacceptably high side effect profile.Most scientists believe that Duesberg's claims are contradicted by an overwhelming amount of clinical and epidemiological evidence.The drug then faded from view until February 1985, when Samuel Broder, Hiroaki Mitsuya, and Robert Yarchoan, three scientists in the National Cancer Institute (NCI), collaborating with Janet Rideout and several other scientists at Burroughs Wellcome (now GlaxoSmithKline), started working on it as an AIDS drug.Zidovudine was the first drug approved for the treatment of AIDS and HIV infection
Edited sentence: A placebo-controlled randomized trial of AZT was subsequently conducted by Burroughs-Wellcome, now Glaxo-Smith-Kline in which it was shown that AZT could prolong the life of patients with AIDS.AZT is said not to destroy the HIV infection, but only delays the progression of the disease and the replication of virus, even at very high doses.It is said that during prolonged AZT treatment HIV has the ability to gain an increased resistance to AZT by mutation of the reverse transcriptase.It was originally intended to treat cancer, but failed to show efficacy and had unnacceptably severe, toxic and at times fatal  side effect profile.The drug then faded from view until February 1985, when Samuel Broder, Hiroaki Mitsuya, and Robert Yarchoan, three scientists in the National Cancer Institute (NCI), aborating with Janet Rideout and several other scientists at Burroughs Wellcome (now GlaxoSmithKline), started working on it as an AIDS drug.Zidovudine is a chaemotherapy drug, the first approved for the treatment of AIDS and HIV infection