based on V scrip data, appears market share is coming at the expense of L/GL
This graph (per ShortFishFry on Stocktwits) would appear to address your point. While I agree that total Omega 3 scripts ("Total market" in below graph) have declined somewhat (due to decline in Lovaza and generic Lovaza numbers), clearly Vascepa's increase in market share is the result of a combination of the significant increases (to which you alluded) in V and concurrent decreases in L + gL numbers.
Because this graph doesn't provide enough detail, I sometimes look at the V TRx change and compare it to the L + gL TRx net change (absolute numbers), in an effort to get a sense of whether V TRx increases, in absolute numbers, equal or outpace change/decrease in L + gL TRx numbers. One week does not indicate a trend, but this week's increase in V TRx was 638, outpacing L and gL net TRx decline of 9. It would be interesting to see monthly figures showing whether V TRx increases are closing in on/overtaking gl +L net decreases such as to indicate that the overall sector downtrend might reverse in the near term.
Along these lines, I remain interested in whether, depending on who is appointed FDA Commissioner, Amarin will seek reinstatement of the ANCHOR SPA and reconsideration of the ANCHOR sNDA. Getting the ANCHOR indication on the label (with no competition in that category) could help V TRx while we wait for REDUCE IT data to be locked, compiled, analyzed and published. Many unknowns likely bear on that question.
Probably more important is the extent to which good REDUCE-IT results would affect overall Omega 3 numbers. I'm anticipating that they would (and will), resulting in eventual sector TRx increase.