GENEVA—Since unveiling its Tecentriq monotherapy win in previously untreated non-small lung cancer, Roche has faced criticism that the diagnostic test it used to identify trial patients might have influenced its results. Not so, says a new analysis.
In Roche’s phase 3 Impower110 trial, Tecentriq (atezolizumab) showed it benefited patients with high levels of biomarker PD-L1—no matter which of three commonly used assays was used to determine the patients who belonged in that group, investigators said in a presentation at the ESMO Immuno-Oncology Congress.
“Overall survival and [progression-free survival] results were consistently in favor of atezolizumab” despite the diagnostics’ “different sensitivities and scoring algorithms,” presenter Roy Herbst said.
In other words, the analysis “showed similar overall survival outcomes … irrespective of” diagnostic assay, SVB Leerink analyst Daina Graybosch put it in a note to clients.
The way she sees it, “these results refute the criticism that Tecentriq’s positive IMpower110 results … were driven by a more selective diagnostic assay (SP142) and increase the competitiveness of Tecentriq” in the previously untreated, PD-L1 high population.
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Tecentriq, which in September showed it could extend those patients’ lives for 7.1 months longer than chemo could, is looking to join Merck & Co.’s Keytruda as the second member of the PD-1/L1 class to win a monotherapy approval in first-line lung cancer. Keytruda’s label instructs doctors to use a specific assay—called 22C3—to sift for PD-L1 high patients who can receive the treatment.
That diagnostic has shown it picks out more eligible PD-L1 high patients than others do, suggesting to Graybosch and her colleagues that “physicians and pathologists will continue to prefer and use 22C3.”
“This could confer some advantage for Merck, as it is the assay in their label,” she noted. But “that said, (Roche’s) exploratory analyses … give rationale to use the results of this assay to choose Tecentriq as well,” she wrote.
Roche, meanwhile, "will continue to investigate which assays are best suited to identify the clinical activity of Tecentriq across different tumor types. We will follow the science and adapt our approach as our understanding evolves," a spokesperson for the Swiss drugmaker's Genentech unit said by email.
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Even if Tecentriq can snag a green light, though, Keytruda won’t be an easy drug to take on in the market, considering it bagged its solo OK all the way back in October 2016.
“The lead and loyalty for Keytruda among oncologists treating NSCLC are strong,” Graybosch wrote to clients in a September note.