A lab worker cuts a DNA fragment for sequencing as part of research to determine genetic mutation in a blood cancer patient. There has been a sharp escalation in the weapons race against cancer, with several high-tech approaches long dreamed of now being put to use.associated pressA lab worker cuts a DNA fragment for sequencing as part of research to determine genetic mutation in a blood cancer patient. There has been a sharp escalation in the weapons race against cancer, with several high-tech approaches long dreamed of now being put to use.

CHICAGO — New research shows a sharp escalation in the weapons race against cancer, with several high-tech approaches long dreamed of but not possible or successful until now.

At a weekend conference of more than 30,000 cancer specialists, scientists reported:

• New “smart” drugs that deliver powerful poisons directly to cancer cells while leaving healthy ones alone.

• A new tool that helps the immune system attack a broad range of cancers.

• Treatments aimed at new genes and cancer pathways, plus better tests to predict which patients will benefit from them.

“I see major advances being made in big diseases” such as breast and prostate cancers, said Dr. Richard Pazdur, cancer drug chief at the federal Food and Drug Administration, which recently announced a new policy intended to speed breast cancer drugs to the market.

The field continues to move toward more precise treatments with fewer side effects and away from old-style chemotherapy that was “like dropping a bomb on the body,” he said.

In fact, an emerging class of “smart bombs” was one of the most hopeful developments reported at the meeting of the American Society of Clinical Oncology.

These are two-punch weapons that combine substances called antibodies, which bond with specific cancer cells, and toxins that are too potent to be given by themselves. A chemical link holds them together until they attach to a tumor cell, releasing the poison inside it and killing the cell.

“This is a classic example of the magic bullet concept” first proposed more than 100 years ago but only now possible with advances in technology, said Dr. Louis Weiner, director of Georgetown Lombardi Comprehensive Cancer Center.

“The antibody basically targets this very toxic drug right to the cancer cell and places it inside the cancer cell where the drug can do its damage” without harming healthy cells nearby, he said.

A large study showed that one such drug — Genentech's T-DM1 — delayed the time until cancer got worse in women with very advanced breast cancer. The drug also seems to be improving survival, although it will take more time to know for sure. So far, women on the new treatment were living more than a year longer than a comparison group of women who were given two other drugs.

Dozens of similar “smart bomb” drugs are in development. Pfizer was to report on one it is testing for certain types of lymphoma and leukemia. Only one such drug is on the market now — Adcetris, sold by Seattle Genetics. The other big news at the conference involved a very different approach: using the immune system to fight cancer.