Longevity escape velocity is a hypothetical situation in which life extending medicine extends life

longer than the time that is passing. For example, in a given year in which longevity escape velocity would be maintained, technological advances would increase life expectancy more than the year that just went by.

Assume for the purpose of this question that before 2100, a therapy is developed which at least two peer reviewed published scientific articles report extends the average human expectancy at 70 years old by at least 4 years.

(In America, the current life expectancy from 70 is about 15.5 years.)

A "therapy" cannot be a recommendation to diet or exercise. However, a therapy can be a prescription drug taken regularly, a combination of drugs, a series of surgeries, or any other such procedure that is not currently a standard medical recommendation for 70 year olds. For the therapy to count, there must be credible evidence that if all 70 year olds received the therapy, their expected lifespans would go up by at least 4 years on average. Therefore, it is not enough that it extends the lives of some subset of 70 year olds.

Longevity escape velocity is said to be achieved if more than one half of 70 year olds who take the therapy within 5 years of its development are still alive after 50 years. In that case, this question resolves positively. If such a therapy is developed but more than half of such 70 year olds are not alive 50 years later, then this question resolves negatively.

If no such therapy is developed before 2100, this question resolves ambiguously.

The date of development of the therapy is the date of the publishing (anywhere it is published) of the first peer reviewed paper that reports the aforementioned life expectancy results of that therapy.