Ongoing Research and Availability
There are currently no CCBs on the WHO list of drug candidates for
SARS-CoV-2 infection:
https://www.who.int/blueprint/priority-diseases/key-action/Table_of_therapeutics_Appendix_17022020.pdf?ua=1.
To date, there is at least one clinical trial registered that employs
CCBs in the context of COVID-19 (NCT04330300, Galway, Ireland). It is
based around the observation that SARS-CoV-2 uses angiotensin converting
enzyme 2 (ACE2) as a cell entry point, and that commonly prescribed
antihypertensives, angiotensin converting enzyme inhibitors (ACE
inhibitors) might have a detrimental effect on patients who contract
COVID-19. The study thus compares patients who remain on ACE inhibitors
throughout their illness with patients who are switched to alternative
antihypertensives, including CCBs. While this work is not concerned with
the mechanism of action discussed above, it will provide useful
information on the potential therapeutic role of these drugs in
SARS-CoV-2 infection.
No patents specifically relating to tetrandrine and the therapy of
SARS-CoV-2 infection were found online (but see Chinese and US patents,
cited above). However, a phase 4 clinical trial of tetrandrine for the
treatment of SARS-CoV-2 was set up in China in March 2020,
https://clinicaltrials.gov/ct2/show/NCT04308317, of one year’s
duration. It is geared towards preventing pulmonary fibrosis, and does
not mention a pharmacological basis for the mechanism of action of
tetrandrine. However, primary and secondary outcome measures are stated
as survival rate and body temperature, respectively, suggesting that the
trial will provide valuable insights into the role of tetrandrine as an
acute therapeutic agent.