If SORAYA succeeds, there are still several reasons to raise some money now:
1) They have a plethora of trials they could run for MS and 632 as well as a new drug to IND besides SORAYA and MIRASOL; these may be a better investment of current equity in return for slightly earlier future returns (before either competition or a patent cliff) than taking a steadfast refusal to dilute at all before SORAYA.
2) A macro market downturn may make raising money less attractive when forced to do so by a trial's end date. This is likely moot because I expect at least a $1.5B valuation should SORAYA read out around 30% ORR under normal circumstances, however the small chance of not having a cash cushion and having to raise money during a market crash is not something I want them to have to do.
3) Finally, doing an ADC launch is more expensive than other types of drugs (small molecule, biologics, though not CAR-T types); manufacturing ADCs is not cheap:
("In fact, Roche decided late last year to spend $200 million to build its own production facility in Basel, Switzerland, to support Kadcyla and another eight ADCs in its clinical pipeline. Custom chemicals firm Lonza, which also manufactures Kadcyla, is investing $15 million to add a second commercial-scale ADC facility in Visp, Switzerland, later this year.")
I think having some clarity on a cash runway all the way to a US launch and hence some flexibility in choosing a ROW partner (perhaps even after MIRASOL reads out) is prudent. We'll see where this thing closes today but from the initial looks of it, the street seems to have been looking for some clarity for funding MS through a domestic trial.