But does it really work in humans?, page-12

An interesting thread.
If you want to compare the success of monoclonal antibodies as medicines with cellular therapy you might gain insights from a 2013 Nature Medicine paper "The meaning, the sense and the significance: translating the science of mesenchymal stem cells into medicine" by Paolo Bianco et al (and also Paul Simmons (MSB)). One reason this paper might interest you is the sentence "If indeed MSCs were affecting tissue injury and repair through paracrine factors as is commonly claimed, then the factors, not the cells, would be the medicine." (see page 40 2nd col, 2nd last para).
The way that monoclonal antibodies work is very well established, and they each have their own specificity for particular epitopes on particular molecules.
Bianco et al is saying - in effect - if the cells are not actually forming repair tissue in the patient's body, then why are cells an important product to test in clinical trials (or later sell). The authors actually say "Then, intravenous injections of cells in patients, as opposed to the pursuit of the factors and their mechanisms at the bench, would turn into the opposite of a true translational approach."