Edit from fucking 2019: this is all obviously wrong, EA is a scam, do all your own analysis of everything if you want to have an impact
It should be emphasized that back-of-the-envelope calculations, such as the one given in this post, ought to be adjusted to account for the fact that interventions can look much more cost-effective than they are, especially when the interventions were only shallowly investigated.
Previously, Givewell has looked into the cost-effectiveness of life sciences funding, as well as publishing a simple estimate of the impact of the average dollar spent on cancer research, which suggested that, in the past, each $2790 spent on cancer-relevant biomedical research in the US added one year of life lived (YLL) to the life of a US resident. Givewell has also interviewed Aubrey de Grey of the SENS foundation. Owencb has previously estimated the cost-effectiveness of funding SENS/ anti-aging research as being around $50 per QALY. Aubrey de Grey has previously been averse to giving explicit cost-effectiveness estimates regarding how many QALYs would be gained per unit of funding supplied to SENS, though he has been clear that SENS's funding needs are "$100 million per year for each of the next ten years".
This part of the post will consist of me using lots of best guesses to produce something vaguely resembling a cost-effectiveness estimate for SENS. You should not take this cost-effectiveness estimate literally.
If SENS needs one billion dollars to ensure that rejuvenation technologies that give individuals 30 extra years of healthy life are available to the public in 30 years, we might (completely arbitrarily) assume that someone else will come along and fund SENS in ten years if we don't contribute to funding SENS today. This means that if we fund SENS today instead waiting for it to be hypothetically funded in ten years from now, about ten times the number of people who die each year would live 30 years of healthy life that they wouldn't have lived otherwise. Given that there are about 57 million deaths per year worldwide, this translates to about 17 billion YLLs lost by waiting ten years to fund SENS; since SENS ostensibly requires only 1 billion of philanthropic funding, this implies that $0.059 of funding for SENS produces a YLL.
Of course, regenerative medicine won't be free to the people receiving it, and I have no idea how to account for this, given that I don't have a good idea of how much regenerative therapies will initially cost. The above estimate hasn't been adjusted to account for the fact that there is a time-delay between when funding is provided, and when the benefits of regenerative therapies are available to the public. Perhaps Aubrey isn't well-calibrated, and the "$100 million per year for ten years" figure is entirely wrong. It may be the case that starting work on SENS's research agenda earlier rather than later would allow certain people who would have otherwise died to live until aging escape velocity is reached, which would have lots of utility. There are plenty of other issues with this cost-effectiveness estimate which I am sure that readers could point out.
The point I wanted to make, though, was that maybe, possibly, SENS is competitive with GiveWell's top charities-- I'm legitimately not sure whether I would fund SENS or GiveWell if I were making a charitable donation today. Does anyone have any further thoughts on this topic?