(Alliance News) - AstraZeneca PLC on Friday said updated results from its Pacific phase 3 trial of Imfinzi showed a sustained and clinically meaningful improvement in overall survival and progression-free survival in lung cancer.
The trial was of patients with unresectable, stage 3 non-small cell lung cancer who had not progressed after concurrent chemoradiation therapy. One in three patients with non-small cell lung cancer are diagnosed at stage 3, at which point most tumours are unresectable - meaning they cannot be removed with surgery.
Before Imfinzi in this setting, there have been no new treatments past chemoradiation therapy in decades.
Results from the updated post-hoc analyses showed an estimated four-year survival rate with Imfinzi of 50% compared to 36% with placebo after chemoradiation therapy. Median overall survival was 47.5 months for Imfinzi and 29.1 months with placebo.
At the maximum treatment course of one year, around 35% of patients treated with the drug had not progressed four years after enrolment compared to 20% with placebo.
Jose Baselga, executive vice president of Oncology R&D as Astra, said: "These unprecedented four-year results reinforce Imfinzi as the established standard of care in unresectable, stage 3 non-small cell lung cancer and set a new survival benchmark in a setting where cure is the treatment goal. With data also at ESMO for Caspian in small cell lung cancer patients, Imfinzi continues to deliver impressive long-term benefits across different types of lung cancer."
In the primary analysis of Pacific phase 3, the most comment adverse events among patients were cough, which 35% experienced compared to 25% with the placebo; fatigue, 24% versus 21%; dyspnoea, 22% versus 24%; and radiation pneumonitis, 20% versus 16% with placebo. A grade 3 or 4 adverse event occurred in 31% of patients treated with Imfinzi compared to 26% with placebo. A total of 15% of patients discontinued Imfinzi treatment due to adverse events compared to 9.8% with placebo.
Astra also posted results from the Caspian phase 3 trial exploratory subgroup analyses in extensive-stage small cell lung cancer. These subgroup analyses were conducted to characterise patients deriving long-term benefit.
Over three times as many patients treated with Imfinzi plus chemotherapy were alive and progression-free for a year or more versus chemo alone, 17% compared to 4.5%.
In all treatment arms, those patients who were progression free at 1 year had a 75% chance of being alive at 2 years. In comparison, those patients whose disease did progress within a year had a 10% change of being alive at 2 years.
Caspian met its primary endpoint of overall survival in 2019, reducing risk of death by 27% in extensive-stage small cell lung cancer.
Separately on Friday, Astra posted five-year data from its Solo-1 phase 3 trial of another cancer drug, Lynparza. This is the longest follow-up analysis for any PARP inhibitor in the first-line maintenance setting.
Data showed that Lynparza improved median time patients lived without disease progression to more than 4.5 years in BRCA-mutated advanced ovarian cancer, compared to just over 1 year with placebo.
BRCA mutations are associated with certain cancers, with around 22% of patients with ovarian cancer having a BRCA1/2 mutation.
PARP is an enzyme in cells that helps to repair damaged DNA, and so inhibiting this enzyme prevents cancer cells from repairing themselves.
The five-year follow-up showed that Lynparza reduced risk of disease progression or death by 67% to a median of 56.0 months compared to 13.8 months with placebo. At five years, 48% of patients treated with the drug remained free from disease progression compared to 21% with placebo. The median duration of Lynparza treatment was 24.6 months compared to 13.9 months with placebo.
Baselga said: "Once a patient's ovarian cancer recurs, it historically has been incurable. Even at an advanced stage, we have shown that maintenance treatment with Lynparza can help patients achieve sustained remission. Today's results further underline the critical importance of identifying a patient's biomarker status at the time of diagnosis to offer a treatment that may help delay disease progression."
Astra is developing Lynparza with Kenilworth, New Jersey-based drug maker Merck & Co Inc as part of a strategic oncology collaboration.
Shares in Astra were up 0.8% at 8,718.00 pence in London on Friday morning.
By Anna Farley; annafarley@alliancenews.com
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