SangStat Medical (SANG) is not yet a household name. But it could become a lifesaver for people with transplants. SangStat makes a product that helps prevent the body from rejecting transplanted kidneys or livers. Such agents are called cyclosporines, and SangStat's version is expected to receive a patent soon--and get approval from the Food & Drug Administration in three to six months. So say some big players who have been accumulating the stock.

SangStat stock, which fell from 41 last summer to 21 earlier this year, has snapped back lately, to 28. And some pros are betting that it's headed higher still. The reason: SangStat's drug, called SANG-35, is similar to Novartis' Neoral, now dominant in transplant care, according to a study presented in May to the American Society of Transplant Physicians. Merrill Lynch Capital Markets cites this report in a recent bullish report on SangStat.

''SANG-35 will offer an economical alternative to patients in this $1.3 billion global market,'' says J. William Tanner, an analyst at Vector Securities International, a research and investment firm focusing solely on health care. If approved, ''SANG-35 will be a big revenue generator,'' he adds.

SangStat has just bought the transplant business of France's Pasteur Merieux Connaught, part of Rhone-Poulenc, to get a marketing base in Europe--which should help in promoting SANG-35.

SangStat has also developed a handheld device called CycloTech, which dispenses a precise dose of SANG-35. Tanner says this will enhance the drug's value, since CycloTech improves transplant results.