There are few diseases that command attention like HIV and AIDS, with more than 1 million people fighting the disease in the United States alone. While there's no cure to the infection, numerous public companies continue to fight against the disease with the latest in HIV treatments and therapies. From HIV leader Gilead Sciences (GILD -1.15%) to major big pharma companies like Merck (MRK -0.11%), there's numerous good options for investors looking to get a piece of the HIV treatment market -- and 2012 proved to be a banner year for the industry.

Gilead wins... again
There's no safer bet in the HIV treatment industry right now than Gilead. HIV fighter Atripla continues to lead the way as a blockbuster drug for the company, and Gilead's stock surged an astronomical 75% in 2012.

Atripla, which combines two drugs -- Gilead's own Truvada drug with Bristol-Myers Squibb's (BMY 0.96%) Sustiva -- continued its strong run in 2012 with more than 12% year-over-year growth through the first nine months of the year. The treatment doesn't lose patent protection until 2021, although Sustiva's patents begin losing protection starting next year -- an event that could negatively impact Atripla's sales.

That's not all that Gilead, the largest AIDS drugmaker in the world, had to offer for the HIV market in 2012, however. Back in July, the Food and Drug Administration approved Truvada for pre-exposure prophylaxis. In layman's terms, Truvada became the first approved drug to reduce HIV risk for unaffected people in high-risk situations.

That's the latest bit of good news for Truvada, Gilead's second-highest seller, which saw sales jump by more than 10% over 2012's first nine months. It's also great news for the HIV community at large: Truvada's new indication is an important step toward HIV prevention, rather than simple treatment. Truvada significantly decreased the risk of HIV infection in two studies that the FDA cited in its approval.

But wait -- there's still more good news for the future out of Gilead's HIV department in 2012. The company's pipeline paid dividends in August, when new HIV treatment drug Stribild won FDA approval. The drug -- which has already been submitted  for European approval -- combines four drugs in one and was shown in a Gilead study to work as effectively as Atripla. While Stribild may not pay off much now -- the drug sold less than $18 million in its first quarter of public sales -- it's expected to help offset the eventual patent expiration of some of Gilead's other HIV medications in 2018. Analysts have already indicated that Stribild could hit multibillion-dollar peak annual sales in the future.

OraSure can't beat Wall Street
Gilead may be the big player in the HIV industry, but the smaller OraSure Technologies (OSUR) has also made some waves in 2012 -- not all of them good.

First, the good news: OraSure made big news when the FDA approved its at-home HIV test in early July of last year. The company's OraQuick test is the first of its kind and a landmark moment for the HIV movement as a whole; identifying and treating the disease early could significantly impact transmission rates of a disease that infects 50,000 Americans annually. Retailers began selling OraQuick in October, according to the company's third quarter report, and it's projected that the company could sell $20 million in sales of the test in 2013.

Now for the bad news: About that third quarter... it did not make Wall Street happy. The company's fourth-quarter projections, which it announced after releasing the earnings statement, estimated a quarterly loss far greater on a per-share basis than most observers projected. That promptly sent skittish shareholders into a fear frenzy, nuking the stock by as much as 22% during the sell-off.

Despite what the OraQuick test means for the HIV market, OraSure's stock didn't recover in 2012 after the third quarter blow-up: Shares are down more than 24% over the past 52 weeks. Don't let the fourth-quarter estimates influence your investing decision, however -- it's the company's long-term outlook that matters. OraQuick's accuracy in the hands of ordinary consumers has drawn some concern, but the company's slow cash burn rate and growing revenues -- up more  than 12% for 2012's first nine months -- should give investors more time to see just how well the HIV test can sell to the public.

Big pharma's big HIV dollars
Big pharma hasn't let the smaller companies dominate the HIV market in 2012, however.

Merck's HIV treatment Isentress may not sell like Atripla, but it quietly became the company's eighth-leading seller in 2012 -- an important milestone with the loss of Singulair hurting Merck's top line. Isentress won't fuel Merck's future with products like diabetes-fighting Januvia and Janumet in the company's portfolio, but it's a solid billion-dollar blockbuster that grew sales by more than 16% through 2012's first nine months. Isentress' patent doesn't expire until 2022, either, giving Merck investors some longevity to breathe easy about.

Viiv Healthcare, the partnership between Pfizer (PFE -0.12%) and GlaxoSmithKline (GSK -0.83%), also made moves in 2012 by submitting approval applications for its dolutegravir, a challenger to Gilead's Stribild. While the drug has shown effectiveness in a phase 3 trial, dolutegravir's likely co-formulation, GSK's Epzicom, could come back to hurt Viiv.

Several studies have shown Truvada to be more effective than Epzicom. With the former patent-protected until 2018, Viiv seems to have given Gilead either a time or efficacy advantage, depending on whether the company co-formulates with Epzicom or choose to wait and use Viread, Truvada's critical component, when it goes off patent.

No stopping the industry
Gilead succeeded brilliantly in 2012, continuing its reign atop the HIV market for another year. While the OraQuick test made waves for OraSure, the company's stock -- driven down by fretful shareholders -- couldn't keep up with the momentum. As HIV continues to spread, however, companies large and small alike will continue to keep hauling in billions of dollars treating the disease -- and health care investors would be advised to keep their eyes open for the latest developments.