The phrase "despite significant effort" is correct and usable in written English.
You can use it to indicate that while a lot of effort was put into something, the desired result was still not achieved. For example: "Despite significant effort, the team was unable to secure the win."
The mounting frustration comes despite significant effort by the California Army National Guard to stop the collection from happening, said.
However, despite significant effort, there are still no approved therapeutic mAbs directed against the largest and most attractive family of drug targets: G protein-coupled receptors (GPCRs).
Despite significant effort, no consistent patterns have emerged concerning T helper (Th) and/or cytotoxic T lymphocyte (CTL) specificities that may be associated with efficient clearance of infection.
Despite significant effort by the Surviving Sepsis Campaign and other initiatives, sepsis remains underrecognized and undertreated.Research indicates that educating providers may improve sepsis diagnosis and treatment; thus, the Stanford School of Medicine has developed a mobile-accessible, case-based, online game entitled Septris (http://med.stanford.edu/septris/).edu/septris/
Despite significant effort, patients with kidney disease have not seen their outcomes improved significantly over the past two decades.
Despite significant effort and progress that has been made over the last several decades, there are still many unknowns about ABA signaling pathway.
Despite significant efforts, all realizations to date rely on stationary sites.
Despite significant efforts, including free uniform offers to get more reception parents to claim, not one has.
Despite significant efforts in the field, the design requirements for various tissue engineering scaffolds have still not been defined precisely.
Despite significant efforts to date, catalytic stability of the silicon photoelectrodes is limited by their poor electrochemical stability.
Despite significant efforts directed toward research on HIV-1 vaccines, a truly effective immunogen has not been achieved.
