(Reuters) – Merck & Co Inc’s cancer drug Keytruda failed a late-stage trial’s main goals of slowing disease progression and extending the life of patients with a common type of liver cancer, the company said on Tuesday.

The results could hamper prospects for the drug, which had received an accelerated approval from the U.S. Food and Drug Administration in November as a treatment for patients with advanced liver cancer who had been previously treated with Bayer AG’s Nexavar.

Keytruda, which is approved to treat several forms of cancer including skin and lung cancer, is Merck’s biggest drug and brought in revenue of $7.17 billion last year.

The late-stage Keynote-240 study was testing the blockbuster cancer drug in patients with advanced hepatocellular carcinoma (HCC) who were previously treated with systemic therapy.

The drug’s continued approval for this indication may be contingent upon the results of confirmatory trials, Merck said.

While patients on the drug did see some improvement in overall survival and disease progression compared to those in the placebo group, the results were not statistically significant.

Even though disappointing, the results are generally consistent with findings from the mid-stage study which led to Keytruda’s accelerated approval, Merck said in a statement.

The drugmaker, whose shares fell about 1 percent in after-market trading, said it is testing Keytruda in 10 clinical trials as a treatment for HCC.

(Reporting by Tamara Mathias in Bengaluru; Editing by Shounak Dasgupta)