Analysts have pegged AbbVie’s leukemia newcomer Venclexta (venetoclax) as a future blockbuster. But unless something changes, England won’t be helping the med get there.

Wednesday, the National Institute for Health and Care Excellence turned down the product—known as Venclyxto in Europe—for routine use on the National Health System. And it wasn’t just the med’s price that sparked the rejection.

As the body laid out in draft guidance, its appraisal committee flagged “substantial uncertainty” within the body of evidence the drugmaker submitted to support the med, which is used to treat subsets of chronic lymphocytic leukemia patients.

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The committee’s concerns included the single-arm design of the med’s trials, which “meant that the results were potentially biased”; the fact that “the trials included relatively few people”; and the source of the data for a trial pitting Venclyxto against best supportive care.

“The patients in the comparator trial did not reflect those for whom venetoclax may be option,” the committee said.

As is common among costly cancer drugs trying to sneak their way past the gatekeeper, NICE took an issue with the product’s price, too. The watchdog normally accepts meds that can deliver a quality-adjusted life year (QALY) at a max cost of between £20,000 and £30,000, and AbbVie’s drug exceeded that range.

Now, AbbVie will continue negotiations with NICE in an effort to flip its decision. "We are ... disappointed with the committee’s decision and will now act quickly to work with NICE through the next step of its decision-making process,” Alice Butler, Medical Director at AbbVie UK, said in a statement.

It’s a setback for AbbVie, which is working to grow its first-to-market BCL-2 inhibitor. Right now, the med is limited to a smaller pool of hard-to-treat CLL sufferers, but it also boasts breakthrough designations in two other uses that would cover far more patients.

As the Illinois pharma’s execs said on the company’s Q4 earnings call last month, they expect Venclexta to bring in just $125 million for 2017, as its current U.S. indication hits within a $300 million market that’s controlled by fellow AbbVie med Imbruvica. But as the company grows its list of FDA nods, analysts expect to see the product net $1.5 billion to $2 billion by the end of the decade.