This would have been the basis of the FDA guidance re the RMAT AA pathway for Revascor for heart failure in its own guidance document: see hypothetical example cited by the FDA of “preliminary clinical evidence that CBER would consider sufficient to demonstrate a product has the potential ti address unmet medical needs with a serious condition" under the second bullet point on p.7. The example given is that of
"a phase 2, dose-finding, intra-myocardial administration of allogeneic mesenchymal precursor cells to patients with advanced chronic heart failure refractory to available medical therapies with dose-dependent improvement in several physiological measurements of left ventricular performance". (Compared to Breakthrough Therapies for non-regenerative therapies, the improvement does not need to be over available therapies.)
For those who are interested, start reading from section C on p.5. Section E on p.9 gives the basis for accelerated approval for ‘regenerative medicine therapies, “for a condition or life-threatening disease or condition” on the basis os a surrogate endpoint. This is used where “the disease course is long and an extended period of time would be required to measure the intended clinical benefit of a drug”.
(20min delay)