Glaxo also owns licensing rights to BioChem Pharma's 3TC, an RTI that won approval last year because it appears to work synergistically with AZT. Between January and March 1996, 3TC brought in revenues of $39,932,000, according to IMS America, and it may ultimately rival AZT in sales. AZT, by comparison, sold $39,997,000 during the same period. Of the three other RTIs now on the market in the United States, IMS America data show that in 1995, the next-best seller was d4T from Bristol-Myers Squibb ($44.5 million), then Roche's ddc ($33.0 million), and Bristol's ddI ($19.6 million). On the horizon are nevirapine and delavirdine, members of a new class of RTIs.
Which of these drugs will dominate the market in the era of combination therapy is anyone's guess. Right now, many analysts seem giddy about impressive early clinical-trial results revealed this February for a combination of AZT, 3TC, and Merck's protease inhibitor. Analysts at Montgomery Securities, in fact, predict that by 2000, 3TC alone--which slows the development of resistance to AZT--will rake in $853 million in the United States. That's $100 million more than these same analysts forecast all of the protease inhibitors combined will gross that year.