CAMBRIDGE, Massachusetts: Can an antipsychotic drug from the 1950s be paired with a 1980s antibiotic to shrink 21st-century tumors? Might an anti-clotting drug help a steroid relieve arthritis? How about a cholesterol treatment and a pain reliever teaming up to tame diabetes?

Alexis Borisy, the pharmaceutical industry’s master matchmaker, is betting they can. And if he is right, he may have found a cheap and quick way to develop a new cornucopia of medicines. Other drug makers are placing similar bets, though perhaps none as single-mindedly as he.

Borisy, 35, is the co-founder and chief executive of CombinatoRx, a biotechnology company dedicated to the proposition that two old generic drugs can together make a powerful new medicine, often for an entirely different disease.

With drug makers big and small struggling to fill their product pipelines, various biotechnology companies share CombinatoRx’s hope that pairing old drugs can be a better business bet than inventing new ones from scratch - which can take years and cost hundreds of millions of dollars, with no guarantee of success.

Others in the hunt include Pozen, a company based in Chapel Hill, North Carolina, developing combination drugs in partnerships with the pharmaceutical giants GlaxoSmithKline and AstraZeneca.

Another, Orexigen, of San Diego, recently went public based on the prospects for two combination drugs it is developing to treat obesity. And Celator Pharmaceuticals of Princeton, New Jersey, which is privately held, has raised more than $40 million from venture capitalists to combine old cancer drugs in a new way.

“We think if we prove this concept clinically we have an almost unlimited pipeline,” said Andrew Janoff, Celator’s chief executive.

Helping propel the trend is the growing supply of raw material: drugs that have lost patent protection, providing a lode of material to test for newfound potential.

Information technology also plays a major role. CombinatoRx (which is pronounced com-bin-a-TOR-ics, as in the mathematics field that deals with combinations), relies on the latest robotic drug-screening technology and software to test several thousand pairs of medicines a day.

At its laboratory in Cambridge, Massachusetts, researchers and robots systematically pair about 2,000 generic drugs with one another, with two million different combinations possible. Each is tested on human or animal cells, to see what happens.

If a drug pair inhibits the cells’ production of inflammatory proteins, for example, that might be reason to start exploring whether the combination might work against arthritis.

Borisy describes it as a “dumb, brute-force, empirical approach” that assumes current knowledge of disease is too limited to predict in advance what combinations might work. The company does, though, give priority to testing pairs it believes have the best chance of working.

While CombinatoRx must still prove its concept can lead to marketable drugs, eight of the company’s randomly arranged marriages, including the drugs for cancer, arthritis and diabetes, have moved into clinical trials - an unusually high number for a company that is only seven years old. Other companies are taking more rational approaches. Orexigen, in creating its main obesity drug, Contrave, took a treatment used for drug and alcohol addiction and combined it with an antidepressant sometimes used to help people quit smoking.

Meanwhile, Celator is focusing on drugs that are already used together to treat cancer. But while doctors now generally use the maximum tolerable dose of each drug, Celator says the ratio of the drugs is what matters more. So the company is developing combination products meant to deliver optimal ratios of the drugs to tumors.

Besides being quicker or cheaper to develop than single new drugs, combinations might also be more effective. Scientists have long known that the biochemical pathways involved in disease are complex, with numerous alternate routes. Trying to interfere with disease by blocking a single point can be like trying to keep traffic from reaching downtown Manhattan by closing a single intersection.

That is why doctors routinely use two or more drugs to treat people with cancer, heart disease, HIV infection and other diseases.

But only recently have single drugs with a one-two punch emerged as a business model in their own right.

Successful combination drugs already on the market included GlaxoSmithKline’s Advair, which pairs two asthma drugs, and Vytorin, which combines cholesterol-lowering drugs from Merck and Schering-Plough that work in different ways.

When they work, combination drugs mean fewer pills to swallow, making it easier for patients to complete a course of treatment - and, thus, helping companies hit sales targets.

Combination drugs can also let a weaker selling medication ride the coattails of a stronger drug, or partly shield a product that has lost patent protection from generic competition. One of the ingredients in Vytorin, for instance, is Merck’s Zocor, which has gone off patent.