There is no proof that these work (same as far Bavi). But there is certainly plenty of evidence that they could. That they are each effective as monotherapy is in itself decent evidence.
That is only partially correct. Right now there is no evidence but that the growth factor inhibitor combination with an IO will provide synergistic benefits. However, since each component is efficacious on its own and their mechanisms of action are distinct, they will almost certainly provide additive benefits. As far as BAVI, there is ZERO evidence that it is efficacious on its own, which means there is ZERO evidence to support the idea it will provide either additive or synergistic benefits when combined with IO.
While you put your hopes in studies that may be pending, big pharma is literally throwing tons of money into a hundred or more studies. The puts Bavi and PPHM even further behind then they were, if that is possible.
As far as selling PPHM, everyone makes their own decisions and lives with the consequences. It isn't all of nothing by the way. You forgot the possibility of selling some PPHM to invest in other companies to lessen risk of total failure. I get the feeling that there are a number of people that went all in on PPHM and remain so because they feel trapped by their losses. There are always options.