"but I'd think the partners (Roche, et. al) have a distinct incentive to keep the exclusivity granted by patent extensions, if only because they would need to go through another round of trials, with all of their uncertainties and costs, with a new bio-similar co-formula."
I see your point and it seems valid as far as the older drugs are concerned. But what about new drugs like ARGX's drug, for instance, which should be approved in December? Presumably, the threat of biosimilars will not begin for at least 10 years later so if the SC formulation is approved, say, in 2023, there is supposed to be a step down in 2024 (or 2025?) in Europe and 2027 in US and I don't see ARGX having an incentive to get co-formulation patents until perhaps 2031.
In any case, we are not the only ones to be unclear about this issue. Analysts seems to be unclear too and unless we get some clarity or significant good news to offset this, I'm afraid the stock will be stuck in a rut. Given the uncertainty about this and lack of visibility into when new products will be approved, I fear that we are fairly valued now. These are the reasons, I think, the P/E ratio seems "low."
I haven't been able to find any peak sales estimates for Phesgo. Have you? I'm not sure how often Perjeta is used with Herceptin and Herceptin sales are declining so it's hard for me to have an educated guess.
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