Newly published guidelines are now available to help doctors better understand when and how to use bone-protecting drugs called bisphosphonates to treat patients with multiple myeloma (MM), a cancer of the immune system cells.

Because bisphosphonates are relatively new, the American Society of Clinical Oncology (ASCO) brought together a panel of cancer doctors, researchers, pharmacists, and a patient using bisphosphonates for her MM, that reviewed evidence from studies to determine how and when the drugs should be used.

The guidelines were published recently in the Journal of Clinical Oncology (Vol. 20, No. 17: 3719-3736). In addition to providing guidance for doctors, they can be helpful for patients as well, said the guideline report's lead author.

"These guidelines make it very clear what benefits patients should receive from these drugs and provide cautionary notes for any possible adverse events," said James R. Berenson, MD, director of the multiple myeloma and bone metastases program at Cedars-Sinai Hospital in Los Angeles.

The panel recommends use of either of the two bisphosphonates now approved in the US, pamidronate and zoledronic acid.

Both drugs can reduce cancer's damage to bone markedly, making future pain from bone damage less likely, and dropping chances a patient will need radiation to the bone, the panel noted.

Although patients who'd had more than one round of antimyeloma treatments lived longer if they took pamidronate, in general the drugs can't be expected to lengthen survival, the panel said.

One of the drugs or the other should be used if X-rays show MM has damaged the bone, the panel recommended. And either can be used if bones are weakening but worse damage hasn't yet begun, the panel said.

Patients on bisphosphonates should have blood and urine tests every three to six months to detect any kidney problems, and if such problems develop, the drugs should be stopped and only begun again once those problems are cleared up, the panel said.

The drugs should be given as long as the benefits outweigh any inconvenience of getting the drugs, which may vary with different patients, the panel noted.

The panel does not recommend bisphosphonates for slow-progressing forms of MM known as smoldering myeloma or indolent myeloma, or for a pre-MM condition called solitary plasmacytoma, if those patients have no signs of bone damage.

And bisphosphonates shouldn't be used for a type of cell disease that can progress to MM, called MGUS (monoclonal gammopathy of undetermined significance), because it's not clear whether the drugs might benefit those patients.

Because pamidronate and zoledronic acid are known to be equally effective, time and cost considerations may be used to help determine which to use, the panel said. Pamidronate costs less but is given over a two-hour period. Zoledronic acid is more expensive but can be given in 15 minutes, the panel said.

Blood tests to show how well the bisphosphonates are working in individual patients may be useful in the future, but aren't ready for use outside clinical trials at this time, the panel said.

Studies have clearly shown bisphosphonates help patients when used in addition to other treatments, said William J. Bensinger, MD, a specialist in blood cell cancers at the Fred Hutchinson Cancer Research Center in Seattle.

"Now, with publication of these practice guidelines, if you are a patient with multiple myeloma, you can be assured these drugs are the standard of care, and that clear guidance on their use is widely available," said Bensinger.