A newly approved drug has shown promise in keeping two rare variations of skin cancer at bay, according to research published in the New England Journal of Medicine.

The drug, Erivedge (vismodegib), is made by Genentech, a U.S. subsidiary of the Swiss drug giant Roche, and was approved by the Food and Drug Administration in January after an expedited review.

It aims to treat basal cell carcinoma, which is the most common form of skin cancer in the world but which is rarely deadly. Basal cell carcinoma accounts for 80 percent of nonmelanoma cancers and some two million new cases in the U.S. each year.

The journal published two studies that show how it helped some patients with two unusual variations of basal cell carcinoma: metastatic basal cell carcinoma and Gorlin syndrome, also known as Basal Cell Nevus Syndrome.

There is no other treatment for Gorlin syndrome, which strikes one in 50,000 people and involves the constant growth of tumors, which are often not deadly but can cause scarring and require frequent surgeries.

Subjects with Gorlin syndrome who took vismodegib developed an average of two new tumors per year, compared with 29 new tumors in subjects taking a placebo, the study said.

When it came to people whose basal cell carcinoma had spread, the study showed 30 percent of 33 patients with metastatic basal cell carcinoma responded to treatment, meaning their tumors shrank.

Forty-three percent of 63 subjects with locally advanced basal cell carcinoma responded in kind.

The phase II study showed a median progression-free survival time of 9.5 months, but overall survival rates have not yet been established.

"It is a landmark day for patients with basal cell carcinoma and all those involved in their care — the greatest advance in therapy yet seen for this disease," said an accompanying editorial by John Lear, consultant dermatologist at Manchester Royal Infirmary in Britain.

However, he pointed out the high rate of adverse effects, including loss of taste, hair loss and muscle cramps, which led to a high rate of people dropping out of the study early.

"Side effects are considerable and frequent, resulting in high rates of drug discontinuation, and these rates will probably be even higher in clinical practice," Lear said.

More study is needed to determine how long the drug may work to ward off cancer, what populations it may best serve, and when it should be optimally administered, he added.