Merck is reportedly discontinuing the development of its SARS-CoV-2 / Covid-19 vaccine candidates, V590 and V591.
According to results, V590 and V591 failed to elicit superior immune responses.
The latest development follows the company’s review of findings from Phase I clinical studies for the vaccines.
Data from these studies showed that V590 and V591 remained well-tolerated. However, the immune responses were inferior to those seen following natural infection and those reported for other vaccines.
The company intends to focus its Covid-19 research strategy and production capabilities on developing two therapeutic candidates, MK-4482 (molnupiravir) and MK-7110 (formerly CD24Fc).
An investigational recombinant fusion protein, MK-7110 targets a new immune pathway checkpoint to modulate the inflammatory response to SARS-CoV-2.
According to interim results from a Phase III study, MK-7110 treatment demonstrated over 50% reduction in death or respiratory failure risk in patients hospitalised with moderate to severe Covid-19.
Last month, Merck entered a supply agreement with the US Government to advance the manufacturing and initial distribution of MK-7110.
Molnupiravir is an oral novel investigational antiviral agent in development in partnership with Ridgeback Bio, currently undergoing analysis in Phase II / III clinical trials in the hospital and an out-patient setting.
Merck Research Laboratories president Dr Dean Li said: “We are grateful to our collaborators who worked with us on these vaccine candidates and to the volunteers in the trials.
“We are resolute in our commitment to contribute to the global effort to relieve the burden of this pandemic on patients, healthcare systems and communities.”
This month, the US Food and Drug Administration (FDA) accepted priority review of the Biologics License Application (BLA) of Merck’s investigational 15-valent pneumococcal conjugate vaccine candidate, V114, for preventing invasive pneumococcal disease in adults.