Trial-based mRCC targeted therapy outcomes stand up in practice
medwireNews: Researchers report findings from a “real world” study that show similar progression-free survival (PFS) rates following targeted treatment for metastatic renal cell carcinoma (mRCC) to those reported in clinical trials.
These results “offer clinicians some confidence that PFS reported from rigorously controlled clinical trials that have highly selective inclusion criteria are… generalizable to the larger population of patients with mRCC,” says the team, led by Amy Abernethy (Duke University Medical Center, Durham, North Carolina, USA).
Despite some variation in practice, “treatment patterns appeared generally consistent with national guidelines,” they add.
The researchers used data from a joint community and academic retrospective mRCC registry on 325 mRCC patients who had received at least one systemic therapy between 2007 and 2011.
Sunitinib was used as the referent treatment because it was considered the first-line standard of care during most of the study period, and of all the treatments studied it was associated with the longest PFS in first- and second-line therapy.
During first-line therapy, the median PFS was 8.9 months with sunitinib, compared with 6.9 months with sorafenib and 4.2 months with temsirolimus. The higher risk for progression with temsirolimus was significant versus sunitinib, at a hazard ratio of 2.46, and remained so after controlling for covariates including risk category and initial disease stage.
The researchers note in Clinical Genitourinary Cancer that the greater risk for progression in patients given temsirolimus likely reflects a poorer prognosis among these individuals. “These patients had significantly more metastatic sites,” they write.
The findings with second-line treatment were very similar, with superior progression-free survival with sunitinib, at 7.0 months, versus 4.6 months with sorafenib, 3.2 months with temsirolimus, and 3.8 months with everolimus. Differences were significant for the latter two treatments versus sunitinib and remained so after adjustment for covariates.
The researchers point out, however, that among patients given second-line sunitinib, the proportion who received it as a first-line treatment was similar to the proportion who received a different agent.
Therefore, “there was a fraction of patients who remained on the same therapy despite documented progression,” the authors comment. This differs from the convention of changing therapy in response to progression.
“Overall, 13.5% of patients received the same treatment in the second line as they received in the first line,” the team reports. “This is an interesting finding from our real world cohort, because there are few data in the mRCC literature about treatment through progression.”
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Lucy Piper, Senior medwireNews Reporter