AstraZeneca rolls out 'unprecedented' 3-year survival data for PD-L1/CTLA4 combo in liver cancer
Months after AstraZeneca touted a major overall survival win for its Imfinzi/tremelimumab combo, the company is ready to spell out what it calls “unprecedented” results.
In a Phase III study dubbed HIMALAYA, 1,324 patients with unresectable hepatocellular carcinoma were randomized into three cohorts: one receiving the STRIDE regimen — a single priming dose of the CTLA4 drug tremelimumab and then PD-L1 inhibitor Imfinzi every four weeks — another taking Imfinzi alone and the third receiving Nexavar (sorafenib), the standard of care.
Not only did the CTLA4/PD-L1 combo cut the risk of death by 22% compared to sorafenib, investigators also reported that almost 31% of patients in that group are still alive at the three-year check-in, compared to just 20% in the sorafenib arm.
“The three-year overall survival rate and favourable safety profile seen with the STRIDE regimen set a new benchmark in this setting,” said Ghassan Abou-Alfa, the principal investigator of the trial and an attending physician at Memorial Sloan Kettering Cancer Center.
Median OS in the Imfinzi group is actually slightly higher than the STRIDE regimen (by 0.2 months), but both are longer than the 13.8 months shown in the sorafenib group.
On the safety side, AstraZeneca reported that more patients treated with the STRIDE regimen experienced Grade 3 or 4 treatment-related adverse events than those who got Imfinizi monotherapy — 25.8% versus 12.9% — but noted it’s still lower than the 36.9% rate for sorafenib.
AstraZeneca has been on a years-long quest to tease out a way to fully unleash the cancer-killing power of the immune system through adding a CTLA4 to its PD-L1, even as it fell far behind Bristol Myers Squibb’s prominent PD-1/CTLA4 combo, Opdivo plus Yervoy. After years of trial and error, recent readouts from studies like HIMALAYA and POSEIDON appeared to be setting the stage for a turnaround.
The HIMALAYA data in particular could cement a filing in the first-line setting — aiming to reach patients who had not received prior systemic therapy and were not eligible for localized treatment. Another PD-L1, Roche’s Tecentriq, is approved for a similar set of patients in combination with Avastin.