1) European sales of herceptin for 2015 was 2 billion$.
2) Details of revenue sharing between Mylan -Biocon is confidential. Your guess is as good as mine
3) With the recent 'global settlement and licence agreement' between Mylan and Roche, launch of biosimilar Trastuzumab will definitely happen provided they get FDA and EMA approval. Also, the Biocons Bangalore facility needs to clear the coming FDA and EMA inspections ( March-April).
Although the 'license effective dates' are confidential, it is reasonable to expect European launch by 2017 -18 and US by 2019-20.
Two questions that troubles me are
1 )Will Roche enter in to similar licensing agreement with other companies planning to launch biosimilar trastuzumab ( Samsung-Bioepis, Celltrion, Amgen)?-probably yes.
2) Is Roche is very confident with their APHINITY trial data that they feel biosimilar trastuzumab won't be a threat to their franchise?
Perjeta (with Herceptin) is already the standard of care in more than 30% of HER2+ breast cancer case (Neoadjuvant and Metastatic). The success of APHINITY trial could potentially allow approval of perjeta in the 'adjuvant setting' also. Adjuvant chemotherapy account for the majority (60%) of breast cancer chemotherapy followed by metastatic (20% ) and neoadjuvant (10%). With the success of APHINITY study, Perjeta, in combination with Herceptin, has the potential to become the standard of care in 90% of HER2+ breast cancer. This will allow Roche to sell Perjeta and Herceptin as a package at same price point as current herceptin alone, but majority of total price in future will come from perjeta and not from herceptin any more. This will seriously dent the prospects of any biosimilar competition. So your third question ' What could be reasonable estimate of revenues flowing to Biocon because of Trastuzumab in Europe and US? will depend on whether perjeta- herceptin combination become the standard of care. In that case the prospects for biosimilar trastuzumab won't be as bright as I previously thought.
Since the Biocon management has given a revenue guidance of 200 million from biosimilars in 2019, they might have already factored in all these and gave a conservative estimate. Also being potentially the first to launch, Mylan-Biocon can garner good market share and revenue before the impact of Aphinity trial kicks in.