Withholding the Cure

Good news! There is finally a cure for that horrible disease. Too bad the cure is owned by Peace and Love Incorporated, who refuse to distribute it because they believe they can squeeze more money out of people who remain sick, or by the evil overlord who wants the people to die off so he can move in and occupy the land.

Withholding the Cure is when the cure really works and it is what people really need, but someone is keeping it from people for their own selfish reasons.

Compare and contrast Manufacturing Victims, which involves therapists keeping their patients in therapy. Then there's withholding medication to keep people in therapy, or withholding therapy to keep people on medication, both of which can be Truth in Television: In Real Life, some people need medication, some need therapy, some need a combination of both, and many need neither.

Sub-Trope of Information Wants to Be Free. Contrast Poison and Cure Gambit, where the villains are usually more than happy to distribute the cure (for a far-from-modest fee, of course), but in any case created the demand for the cure by starting the actual disease!

For simplicity's sake, no Real Life examples unless you have documentation, aside from media reports on people's perceptions.

Anime&Manga

 * Wapol of One Piece, during his reign of Drum Island, removed as many doctors he could find from his kingdom, save his own personal staff of 20. If any citizen needed medical attention, they had to beg him for it.

Comic Books

 * In the Marvel Universe:
 * Wakanda (the home nation of the Black Panther) has had the cure for cancer for centuries but refuses to release it, at least when written by Reginald Hudlin.
 * Doctor Doom apparently has a good method of treating burn victims, which he's withholding because he's ... well ... Doom. He was talked into using it once to save Storm, though.
 * In Doctor Strange: The Oath, Doc retrieves a magical elixir that has the power to "erase what troubles the mind of man," hoping it can save Wong's life. It turns out to be the Cure for Cancer (and everything else), which causes a corrupt pharmaceuticals company to send an assassin to shoot Strange and steal the elixir.
 * C-list character Cardiac became a vigilante / superhero when his brother died because of corporations using this policy.
 * The Invisibles has, as one of its many conspiracy subplots, the agents of the Conspiracy being in full possession of the AIDS vaccine... which they engineered before they released AIDS into the world, so that they could chart its influence among "target populations."

Film

 * In Johnny Mnemonic, the world is in the grips of a pandemic, and an Evil Drug Company is chasing the title character to regain a cure locked in his Neuro Vault. As long as the cure is suppressed, the Evil Drug Company keeps making billions off the watered-down cure, Paralon-B. "Treating the disease is more profitable than curing it!" Cue gunfights.
 * The Evil Drug Company even went so far as to deny the cure to its own top executives. So at least they were consistent.
 * In Mission Impossible 2, a good scientist spliced countless influenza viruses together into a super-influenza as part of the process of creating a universal cure for influenza. That worked out perfectly, and would have been worth billions. Unfortunately, he didn't realize he was working for an Evil Drug Company. They realized that his superflu would be worth hundreds of billions to the right buyer, and that a superflu outbreak would make a universal cure worth trillions. Cue gunfights.
 * In one movie which may or may not share its name with Phase IV, investigation on some mysterious murders leads to the discovery that a laboratory had discovered a cure for AIDS, but decided to murder everyone involved to keep selling existing treatments.
 * In Ultraviolet, demonizing hemophages as monsters instead of treating them as victims of disease enabled the Evil Drug Company has become the "Militant Medical Establishment" known as the ArchMinistry. Unfortunately, they did too good a job of hunting them, and by the time of the movie needed a new threat to "protect" the world from - a "human antigen" cultivated inside of a MacGuffin Boy. Once it's released, people will have to line up at ArchMinistry to get the cure or die. Cue Gun Kata.

Literature

 * In Abarat, Christopher Carrion withheld a cure for a beast boy's condition (his name escapes me) in return for the boy's unwavering loyalty.
 * Opal Koboi in Artemis Fowl does this.
 * Crake pulls this one on the entire world, creating a wildly contagious hemorrhagic virus which he then implanted in supplement pills. He had the cure (and had indeed ensured that at least one person was immune to the virus) but had no plans to distribute it, since his Evil Plan hinged on most or all of the human race dying.
 * In Poison Study, Yelena is poisoned early on with something called Butterfly's Dust that will kill her if she doesn't get a daily dose of the antidote from her keeper.

Live Action TV

 * In the Doctor Who episode "Dalek", the villain brags about having discovered a cure for the common cold—which he isn't going to give to anyone, as it gets him more money if he just sells the existing medication.
 * There was an episode of Barney Miller where the perp was a research scientist who had destroyed the property of his former employers because they refused to let him research the cure for [some disease] on the grounds that it wasn't fatal and there were too few sufferers for a cure to be profitable. Barney managed to talk his former boss into dropping charges and rehiring the guy, partly with the argument that by the time the cure was developed there may be an epidemic, "with any luck."
 * Played with in an episode of Star Trek: The Next Generation. A race contracted a plague and believes they need continued treatments provided by another race to stay alive. Dr. Crusher, however, discovers that the plague has been cured, and it's only the withdrawal symptoms of the treatment that make them think they still need it. The other race are very aware of this and continue to exploit them, as their economy depends on it. While the Prime Directive forbids Picard from revealing the truth to the wronged race, he finds a way to correct the situation by refusing repairs to their few remaining ships. Without the ships, they will have no way to get the cure and will eventually realize they're not actually sick.
 * Not to mention that notorious time in Enterprise when Archer decided to let an entire species die from a disease he had the cure for so that another race would have an "evolutionary breakthrough".
 * Merlin Uther does this when Merlin is poisoned, intent on teaching Arthur a lesson.

Video Games

 * In Dead Rising 2, Zombie Infectees can indefinitely delay their transformation into zombies via daily doses of Zombrex. There are accusations that the Evil Drug Company that makes the drug is working to prevent a cure from being discovered for economic and political power. Cue gunfight.
 * In Case West,
 * This is one of many conspiracies present in Deus Ex - taken Up to Eleven as the people who control the treatment also created the plague.
 * The prequel, Human Revolution has an variation. The company Versa Life,, makes Neropozyne, a drug that prevents the human body rejecting mechanical augmentations. It is the only drug known to do this, meaning it is necessary to most augmented people and as a result had made the company a lot of money.  These actions kick start the events of the game. By the end it is revealed that
 * In Crackdown 2, is secretly withholding the cure to the Freak virus and  is trying to pressure them to release it. However,

Web Comics

 * A 2010 story arc in Oglaf played with this.

Western Animation

 * The DCAU style animated movie Superman: Doomsday briefly mentions this as a Kick the Dog moment. Lex Luthor has found a cure for muscular dystrophy... but he's holding them back until they can slow it down to a lifetime treatment and make more money, as he's not satisfied with the $300 billion he estimates it would already make him.

Real Life

 * The Tuskegee syphilis experiment. A clinical study held by the US government for fifty years on the progression of syphilis in southern Blacks. Not only did they withhold treatment, but they refused to tell the subjects what they were sick with!
 * Specifically, when the study started, it involved treating syphilis with an expensive and not very effective treatment. When the funding got reduced, they couldn't afford the treatment. Instead, they just continued to study the patients, while telling the patients they were being treated, so they could study the progression of the disease. Then, during the course of the study, a cheap and effective cure became available, but the doctors in charge realized that curing the patients would put an end to their research.
 * Every time there is a new disease of any type, a lot of people seem to think this is in effect.