A Rare QoL Study That Could Change Practice

Nick Mulcahy

February 14, 2020

SAN FRANCISCO — Practice-changing studies in cancer care are almost always the result of an improvement in efficacy that "moves the needle," usually in terms of progression-free or overall survival.

But here at the Genitourinary Cancers Symposium (GUCS) 2020, new data from a major prostate cancer trial may represent a rare practice-altering study that has quality of life (QoL) as the agent of change, said an expert not involved with the study.

The new study comes out of the multiplatform STAMPEDE trial, which used both abiraterone and docetaxel in the treatment of men with locally advanced or metastatic hormone-sensitive prostate cancer.

Both treatments improve overall survival (OS) in this setting, but there was no head-to-head comparison in STAMPEDE or in any other trial.

So investigators, led by Allison Hunt, MD, University College London, United Kingdom, asked: In STAMPEDE, did QoL differ sufficiently between treatments (over 2 years) to have an impact clinical decision making?

The answer is that QoL did differ ― but not by as much as the investigators aimed to find.

Average global QoL score, which was the primary outcome, was compared between patients treated with abiraterone (n = 342) and those treated with docetaxel (n = 173) at 12, 24, 48, and 104 weeks (ie, 2 years).

Global QoL scores were +3.9 points higher (95% confidence interval, 0.6 – 7.2; P = .02) over 2 years for patients treated with abiraterone.

But an overall absolute difference of >4 points was predefined as "clinically meaningful," and the results fell just short of that.

Still, the results "should be considered when discussing treatment options with patients," concluded Hunt and colleagues.

Alison Birtle, MD, Royal Preston Hospital, Fulwood, United Kingdom, who enrolled patients in the trial at her hospital but is not an author on the new study, plans on following the authors' advice – and discussing the results with men in her clinic.

She said the QoL differences seen in this trial are "potentially practice changing" ― in her home country of England, at least, where docetaxel is mostly used because abiraterone is not reimbursed in this setting of hormone-sensitive advanced disease.

In the United States and elsewhere, both docetaxel and abiraterone are used in this setting, and physicians present the two drugs as treatment options that have different qualities, including cost and treatment duration.

"I was really surprised at the findings of this poster," Birtle told Medscape Medical News.

She said that it was expected that there would be a dip in QoL for men in the docetaxel group during the 18-week treatment period, but the expected return of QoL (equal with that of the abiraterone group) never materialized.

"After chemotherapy, there is still a substantial difference between the two arms," she observed. "The men [on chemo] never get back to the global functioning they had before the start of treatment.

"Abiraterone keeps somebody functioning for longer," Birtle summarized. "We see a lot of men who want to maintain their quality of life and have as little disruption as possible to their day-to-day activities."

Hunt commented on what was surprising to the study authors. "We expected patients treated with docetaxel would have a declining quality of life in the first year. But what we didn't know was that in the second year, the quality of life [among the chemotherapy patients] never exceeded those patients treated with abiraterone," she told Medscape Medical News.

She stopped short of endorsing abiraterone over chemo on the basis of the results, but added: "At the moment, quality of life may be the thing that distinguishes between the two."

Talk to Patients

Birtle explained how she interacts with men who present with this range of "high-risk" prostate cancers (ie, the STAMPEDE population ― those with nonmetastatic disease but with Gleason score 8–10, a prostate-specific antigen level >40 mL, and/or disease of stage T3 or T4; and those with nodal disease).

She said that she presents the choice as either 18 weeks of treatment with docetaxel or 2 years with abiraterone with monitoring every month or so for liver function and blood pressure, two potential adverse events.

On the basis of those options, plenty of men choose docetaxel, she said. The choice is also influenced by lack of reimbursement for abiraterone.

But study author Hunt suggests that "if you had a choice between the two, you would recommend that patients go on abiraterone on the basis of quality of life."

Birtle will include data from the new study in her conversations with patients, including the findings on pain.

In the study, pain scores were significantly higher over the 2 years among patients treated with docetaxel. The main reason for the pain was peripheral neuropathy, which occurs in about 15% of Birtle's patients who receive chemotherapy.

Birtle also commented on another finding in the QoL analysis ― there was no difference in cognitive function between the two treatment groups, although some difference had been anticipated because of the effect of "chemo brain" with docetaxel.

The study was funded by the Cancer Research UK; the Medical Research Council; Janssen, the makers of abiraterone; Sanofi, the makers of docetaxel; and other pharmaceutical companies. Multiple study authors have financial ties to drug companies who sponsored the study.

Genitourinary Cancers Symposium (GUCS) 2020: Abstract 14. Presented February 13, 2020.

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