Federal drug regulators have approved a new formulation of a long-used cancer medication that dramatically cuts the time needed to administer it — from hours to just a few minutes.

The drug, Rituxan Hycela, is aimed at patients diagnosed with any one of three common cancers of the blood. It promises to end, at least as far as this medication is concerned, one of the tedious rituals of cancer treatment: confinement to a large chair, sometimes for hours, while the drug is slowly infused.

The new version requires five to seven minutes for a complete dose to be injected under the skin, said Dr. Amy Sharma, a hematologist and oncologist at Monter Cancer Center in Lake Success.

This formulation is based on the same proprietary antibody — rituximab — that underlies the original drug, Rituxan. Both medications are products of pharmaceutical giant Genentech. The U.S. Food and Drug Administration approved the injectable version on June 22.

“Traditionally, rituximab is given intravenously, and it’s a large amount of fluid that can take anywhere from 90 minutes to six hours” for complete infusion, Sharma said.

By contrast, the new drug is given in combination with an enzyme called hyaluronidase, which facilitates its absorption. Genentech expects the new version to be available in cancer treatment centers in about a week.

“The subcutaneous form is concentrated, so there is less fluid,” Sharma said. “With a number of these novel agents, drug developers are trying to see if they can be given this way, in just a few minutes.”

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The new formulation, like the original, addresses follicular lymphoma, diffuse B-cell lymphoma and chronic lymphocytic leukemia, the most common forms of the disease, Sharma said.

FDA approval was based on a series of studies involving more than 2,000 patients. In one of those investigations, 77 percent of patients reported a preference for the injection over the longer infusion because they spent less time in treatment.

The new formulation is not a replacement for the older version, but an option for patients who may prefer spending less time in cancer therapy.

Rituxan’s original formulation is widely used across a spectrum of medical conditions. It also is prescribed for rheumatoid arthritis and rare autoimmune disorders. The injectable is for cancer only and will not be available to patients with other conditions, FDA officials said.

The original formulation, however, is a mainstay on the World Health Organization’s list of Essential Medicines.

Cancers of the blood start in cells that are part of the body’s immune system and usually are detected when patients notice such telltale symptoms as swollen lymph nodes, fever, fatigue or easy bruising and bleeding.

The American Cancer Society defines this group of cancers as among the most common malignancies, accounting for an estimated 4 percent of all cancers. Men tend to be affected at a slightly higher rate than women, and whites more frequently than blacks or Asians. The cancer society estimates 72,240 people will develop one of these common forms of lymphoma this year and 20,140 will die.

Having a friendlier treatment strategy, which inadvertently provides patients with more personal time, arrives amid a flurry of innovative advances in cancer treatment for a variety of malignancies.

In early June, Keytruda, a Merck drug based on another proprietary antibody, also was approved by the FDA. It is capable of zeroing in on cancers with a specific genetic signature, regardless of where this DNA manifests in the body.

By highlighting the deadly cancer signature, the drug essentially signals the body’s immune system to descend on the aberrant tissue to destroy it.

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Keytruda and the two Rituxan drugs technically are known as monoclonal antibodies, which at the molecular level are structurally shaped like a letter “Y,” just as antibodies produced naturally by the immune system are shaped. The drugs use each “arm” in the Y, and the tail as well, to aid in the destruction of tumor cells.

The rituximab antibodies are highly sophisticated in how they address cancer, Sharma and other experts said. The original formulation was approved by the FDA in 1997 and for years has been one of Genentech’s biggest global sellers.

“With the tips of each short arm, the antibody recognizes and attaches to the CD-20 protein” found on the surface of lymphoma cells — while the tail, or long portion of the Y, marshals warrior components of the immune system, said Dr. John R. Gerecitano, a hematologist and oncologist at Memorial Sloan Kettering Cancer Center in Manhattan. Working as an assault squad, these members of the immune system punch holes in cancer cells, devour them and carry away the ravaged fragments as biological debris.

Gerecitano said studies have shown that the new formulation is comparable to the original drug, which has helped improve cure rates. The new version, he said, will not cost more than the slow-delivery formulation.

For patients with diffuse B-cell lymphoma, for example, Genentech officials estimated Thursday that a full course of treatment would be $48,600. By comparison, Keytruda costs about $156,000 for a year of therapy.

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Gerecitano said he is looking forward to offering the new medication to patients.

“Infusion time is shorter; nurses don’t have to start an IV,” he said. “This should work out well for patients and nurses.”