LONDON (Reuters) - AstraZeneca’s pill Tagrisso cut the risk of lung cancer progressing by 70 percent compared to standard chemotherapy in a major clinical trial, lifting prospects for a drug that is key to the company’s lofty long-term sales goals.

A sign is seen at an AstraZeneca site in Macclesfield, central England May 19, 2014. REUTERS/Phil Noble/File Photo

The medicine is designed to help cancer patients with certain genetic mutations that are very common in China and other parts of east Asia.

Tagrisso is already on the market, winning early approval based on mid-stage studies and selling $276 million in the first nine months of 2016, but AstraZeneca was required to produce a confirmatory Phase III randomized study detailing its benefits.

Results released on Tuesday showed that Tagrisso, given as a second-line treatment, helped patients live a median 10.1 months before their cancer worsened, against 4.4 months for those on chemotherapy. Tagrisso patients also had fewer drug-related side effects.

AstraZeneca said it would continue to monitor patients to see if the improvement in progression-free survival also translated over time into increased overall survival.

The lung cancer pill is a key component of AstraZeneca’s target to lift sales to $45 billion by 2023. The company set that goal in response to a takeover attempt by Pfizer in 2014, with Tagrisso forecast to contribute $3 billion.

At the time, many analysts viewed the Tagrisso target as highly ambitious. Yet consensus forecasts have now risen to $2.5 billion for 2022, according to Thomson Reuters data, helped by its strong launch and the failure of some rival products.

Sean Bohen, AstraZeneca’s chief medical officer, told Reuters the latest data showed “a pretty extraordinary benefit”, especially as Tagrisso also produced better results than chemotherapy in patients whose cancer had spread to the brain.

Brain tumors are an important consideration in lung cancer, since 25 to 40 percent of patients have brain metastases at some point in their disease.

Results of the trial, involving 419 patients whose disease had progressed after using a so-called EGFR inhibitor drug such as AstraZeneca’s Iressa or Roche’s Tarceva, were presented at the World Conference on Lung Cancer and published online in the New England Journal of Medicine.

AstraZeneca is also assessing Tagrisso as a first-line treatment in a non-small cell lung cancer clinical trial that will report results next year.

The drug, already approved in major Western markets and Japan, is currently under fast track review in China, where nearly half of lung cancer patients are thought to have the EGFR mutation. By comparison, EGFR-mutated lung cancer accounts for only 10-15 percent of cases in Europe and the United States.