Eli Lilly, GlaxoSmithKline-Vir release positive but difficult-to-interpret combo antibody data
As variants threatened Eli Lilly’s solo Covid-19 antibody bamlanivimab, the company teamed with rivals on a potential combo approach. Now they’ve declared interim success, though it’s not clear whether the results support the combo or just show how good their rival’s is alone.
The Indianapolis pharma on Monday announced that a combination of bamlanivimab and the GlaxoSmithKline-Vir antibody VIR-7831 successfully reduced viral loads in a Phase II study. Low-risk patients who received the drug after diagnosis saw a 70% greater reduction in virus after 7 days than patients on placebo. There were also statistically significant viral reductions after days 3 and 5.
The data show a clear benefit over bamlanivimab alone, which HHS has already taken out of circulation because they believe it’s insufficiently effective against variants. In bamlanivimab’s pivotal trial, no dose of the solo antibody showed a statistically significant difference in viral load from placebo at any time point. The Vir-Lilly combo also showed a larger reduction in viral load at day 7 than Lilly’s now-authorized combo of antibodies showed at day 11.
Still, comparisons are difficult. For one, the data come from just 202 patients in a trial that is slated to enroll 1,000 people. The companies also used different endpoints than Lilly did in its earlier studies, looking at viral loads after a week as opposed to 11 days. (After Eli Lilly and Regeneron released the first results for their antibodies last fall, outside experts and the companies themselves pointed out that because most patients clear the virus after 11 days on their own, it was difficult to show a difference with the drug.)
Moreover, no one besides GSK and Vir has any idea how well VIR-7831 reduces viral loads on its own. The partners released Phase III data earlier this month, announcing the drug reduces hospitalizations by 85% — a figure as good as or better than any of the other Covid-19 antibody efforts.
Vir, though, did not release any other details, including on viral loads. Without that, it’s difficult to determine whether Lilly’s positive data are a result of the additive or synergistic effects of combining bamlanivimab and VIR-7831, or whether VIR-7831 is doing all the virus-neutralizing work and bamlanivimab is just along the ride.
Lilly bet on bamlanivimab early in the pandemic, teaming with the then-little known biotech AbCellera to develop what would ultimately become the first antibody treatment authorized for Covid-19. They won $1.8 billion in government contracts to distribute the drug in the US.
Experts, though, continually raised questions about the effectiveness of the dose the FDA authorized — it missed the primary endpoint — and as antibody-resistant variants spread throughout the US, HHS decided to stop administering bamlanivimab in a handful of states.
Last week, they stopped administering it nationwide. It will only now be used in combination with Lilly’s other antibody, in a cocktail that proved more effective in pivotal trials but which lab data suggest may also be susceptible to variants.
Vir’s antibody, by contrast, appeared effective against variants in lab studies. The company filed on Friday for an EUA based off the data suggesting the drug can dramatically reduce hospitalization. Although they have lagged behind Lilly and Regeneron through much of the last year, the antibody’s apparent ability to neutralize variants could give the company an upper hand in the pandemic’s latter stages.