Bryostatin 1 is a potent modulator of protein kinase C (PKC).
It showed activity in laboratory tests in cells and model animals, so it was brought into clinical trials.  As of 2014 over thirty clinical trials had been conducted, using bryostatin alone and in combination with other agents, in both solid tumors and blood tumors; it did not show a good enough risk:benefit ratio to be advanced further.
It showed enough promise in animal models of Alzheimers disease that a Phase II trial was started by 2010; the trial was sponsored by the Blanchette Rockefeller Neurosciences Institute. Scientists from that institute started a company called Neurotrope, and launched another clinical trial in Alzheimers disease, preliminary results of which were released in 2017. 
Bryostatin has also been studied in people with HIV.