Novel Therapies Beat Back Stubborn Cancers

Several in the development pipeline show promise against lung, kidney cancers

SATURDAY, June 3, 2006 (HealthDay News) -- A number of new cancer drugs are showing encouraging results against such obstinate adversaries as lung and kidney cancers.

Researchers from around the world presented the promising findings Saturday at the American Society of Clinical Oncology (ASCO) annual meeting, in Atlanta.

The investigational drug Tykerb {lapatinib} improved survival and slowed cancer growth in patients with advanced renal cell carcinoma, a form of kidney cancer that has not responded to conventional therapy.

Earlier Saturday, scientists announced that Tykerb, when given in conjunction with chemotherapy, also delayed breast cancer progression in women who were no longer responding to Herceptin.

Only about 15 percent of patients with this type of kidney cancer respond to standard immunotherapy treatment.

Epidermal growth factor receptor (EGFR) is one of the major growth factors fueling renal cell carcinoma, explained study author Dr. Alain Ravaud, of University Hospital of Bordeaux and University Victor Segalen, in Bordeaux, France.

Tykerb, which is taken orally, works on two enzymes that are part of the EGFR pathway.

This study involved more than 400 patients with advanced renal cell carcinoma who were not responding to traditional immunotherapy. Participants were randomized to receive either a hormonal therapy or Tykerb daily for 12 weeks.

Although overall survival between the two groups did not differ, patients with high levels of EGFR (60 percent of the patient population) saw a "dramatic" increase in survival with Tykerb, Ravaud said. Time to progression of disease was 15.1 weeks in the Tykerb group and 10.9 weeks in the control group; overall survival in the Tykerb group was 46 weeks vs. 37.9 weeks in the other group.

Side effects were mostly mild and reversible, he added.

"This drug does work in a select group of people with a modest improvement in response rate and survival," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. "But we have to remember that progress is built on small steps, and this small step appears to be real."

"We're also becoming more refined in targeting and, as we go forward, we are going to find more focused treatments," he added. "This is an example of a focused treatment as we improve our science."

More positive news came in the form of Sutent {sunitinib}, a drug that shrank tumors or prevented disease progression in about half the test patients with advanced non-small cell lung cancer who were not responding to standard therapy.

Approximately 85 percent of lung cancer patients have this form of the disease. And the prognosis is notoriously poor.

"New therapies are needed because the average patient with lung cancer diagnosed with metastases outside the lung survives about one year," said study author Dr. Mark A. Socinski, of the University of North Carolina, Chapel Hill.

Sutent, which also comes in pill form, was approved by the U.S. Food and Drug Administration earlier this year to treat advanced kidney cancer, as well as a rare type of stomach cancer. It was the first cancer drug to be approved for two indications simultaneously.

All of the 63 patients included in the lung cancer trial had run through the gamut of available therapies. About 10 percent had shrinkage of their tumors, and 40 percent saw their tumors stabilize after eight weeks. Three patients died, possibly from complications of the disease, not therapy.

Other trials presented at ASCO looked at even more novel ways to curb the devastation of several different cancers.

Apo2L, a new drug that trips the "suicide" mechanism in cancer cells, halted cancer growth in more than half of the patients assessed.

Although this was only a Phase I trial, one 59-year-old patient had a 70 percent response within eight weeks of receiving the drug. Overall, about 56 percent of patients in eight weeks had stabilized their disease, a response characterized as "reasonably good," by study author Dr. Roy Herbst, of the M.D. Anderson Cancer Center, at the University of Texas in Houston.

In all likelihood, if developed and approved, the drug will be combined with other agents to treat patients.

Another anti-cancer drug, YM155, shrank tumors in some patients with non-Hodgkin lymphoma and hormone-refractory prostate cancer that had not responded to conventional chemotherapy.

"It showed impressive anti-tumor activity for a phase I drug," said study author Dr. Anthony W. Tolcher, director of clinical research at the Institute for Drug Development, in San Antonio.

One patient had an almost complete response and, after undergoing more chemo and a bone marrow transplant, remains disease-free after 18 months. Two more non-Hodgkin lymphoma patients are still responding to the therapy after more than 10 and 15 months. Two of nine prostate cancer patients showed more than a 50 percent reduction in their PSA levels, a marker of prostate cancer.

More information

For more on targeted cancer therapies, visit the National Cancer Institute.

SOURCES: Len Lichtenfeld, M.D., deputy chief medical officer, American Cancer Society; June 3, 2006, American Society of Clinical Oncology news conference with Alain Ravaud, M.D., Ph.D., University Hospital of Bordeaux and University Victor Segalen, Bordeaux, France; Mark A. Socinski, M.D., University of North Carolina, Chapel Hill, N.C.; Roy S. Herbst, M.D., Ph.D., M.D. Anderson Cancer Center, University of Texas, Houston; Anthony W. Tolcher, M.D., director, clinical research, Institute for Drug Development, San Antonio
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