CLL14: What the Leukemia Trial Found

The question nobody had answered

Chronic lymphocytic leukemia is usually a disease of older people. SEER, the federal cancer surveillance program, records that it is diagnosed most often between the ages of 65 and 74.

By that age many people also have heart disease, or kidney impairment, or diabetes. Trials had largely studied fitter patients, so the group most likely to actually have CLL was the group with the least evidence.

CLL14 was built for them. It asked whether a fixed twelve-month course of two drugs, with no traditional chemotherapy in it, could beat the standard chemotherapy-based option in exactly that population.

Who was in it

The published report describes 432 people with previously untreated CLL who also had other health problems. They were randomly assigned, 216 to each arm.

Entry required either a score above 6 on the Cumulative Illness Rating Scale, a measure of how many organ systems are impaired, or a calculated creatinine clearance below 70 ml per minute, meaning reduced kidney function.

The median age was 72. The median illness score was 8. The median creatinine clearance was 66.4 ml per minute. This was, by design, not a healthy group.

Trial at a glance

Field	Detail
Trial	CLL14
Registry number	NCT02242942
Phase	3, open-label, randomized
Participants	432 randomized (216 per arm)
Population	Previously untreated CLL with coexisting conditions
Comparison	Venetoclax plus obinutuzumab, fixed 12 months, versus chlorambucil plus obinutuzumab
Main measure	Progression-free survival, assessed by the investigator

What the two drugs do

Venetoclax blocks a protein called BCL2. Healthy cells die on schedule when they are damaged or old, a process called apoptosis. BCL2 blocks that self-destruct switch, and CLL cells make too much of it, so they stop dying. Venetoclax takes the block off.

Obinutuzumab is a monoclonal antibody. It binds CD20, a marker on the surface of B cells, and flags them for destruction by the immune system.

Neither is classical chemotherapy. The comparison arm, chlorambucil, is. It is an old oral chemotherapy drug that damages DNA in dividing cells.

What the trial found

After a median follow-up of 28.1 months, the trial counted 30 events — the cancer growing or the person dying — in the venetoclax arm, against 77 in the chlorambucil arm.

The hazard ratio was 0.35, with a 95 percent confidence interval of 0.23 to 0.53 and p<0.001. In plain terms, the risk of the cancer progressing at any given moment was about 65 percent lower.

At 24 months, 88.2 percent of the venetoclax group were alive without progression, against 64.1 percent of the chlorambucil group.

The benefit also showed up in the hardest subgroups. People with a TP53 deletion or mutation, and people with unmutated immunoglobulin heavy-chain genes, both did better on venetoclax. Those two features have long predicted poor outcomes.

Side effects were roughly comparable. Severe neutropenia — a shortage of the white cells that fight bacteria — occurred in 52.8 percent versus 48.1 percent. Severe infections occurred in 17.5 percent versus 15.0 percent. Deaths from any cause were 9.3 percent versus 7.9 percent, a difference the authors report as not significant.

Why "fixed duration" is the headline

Many targeted treatments for CLL are taken indefinitely. You start, and you keep going until the drug stops working or the side effects become unbearable.

CLL14 tested a course with an end date. Twelve months, then stop. That changes the shape of someone's life, the cumulative side effect burden, and the cost.

Our page on what standard of care means in a trial explains why a control arm dates so quickly, and our guide to leukemia covers how the different types differ.

When CLL is usually found

Many people with CLL have no symptoms at all, and the disease is picked up on a routine blood count showing a raised lymphocyte number. Reasons to have blood checked include:

• Swollen, painless glands in the neck, armpit, or groin lasting more than a few weeks.
• Tiredness that rest does not fix, sometimes with breathlessness on mild effort.
• Drenching night sweats, or a fever with no infection behind it.
• Weight loss of more than about a tenth of your body weight without trying.
• Frequent infections, or infections that take unusually long to clear.
• Fullness or discomfort under the left ribs, from an enlarged spleen.

A diagnosis of CLL does not always lead to treatment. Many people are monitored for years first.

What this trial cannot tell you

• Progression-free survival was the main measure, not overall survival. At 28.1 months the death rates were similar and the difference was not significant.
• Follow-up was under two and a half years. Whether the advantage holds over a decade is a separate question.
• Chlorambucil plus obinutuzumab is not the comparison most people face now. Several other options have arrived since.
• Everyone here was previously untreated and had coexisting conditions. The result does not transfer to fitter or younger patients, or to relapsed disease.
• Venetoclax needs careful ramp-up dosing because of tumor lysis syndrome, a flood of contents from rapidly dying cells that can damage the kidneys. That is a real logistical requirement, not a footnote.
• SEER records five-year relative survival for CLL at 90.2 percent overall. That is a group average from people diagnosed years ago, and it describes populations rather than individuals.

Sources

• N Engl J Med 2019: Venetoclax and Obinutuzumab in Patients with CLL and Coexisting Conditions (CLL14), PMID 31166681 — record retrieved via NCBI eutils
• ClinicalTrials.gov API v2 record for NCT02242942
• NCI SEER Cancer Stat Facts: Chronic Lymphocytic Leukemia
• NCI: Leukemia—Patient Version

How this article was prepared

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

Cancer Explained is published by the National Cancer Information Foundation. It is not medical advice and does not suggest a test or treatment.

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