Entyvio serious side effect of PML

For those like myself concerned about the very serious (potentially terminal) PML (progressive multifocal leukoencephalopathy) disease side effect from using Entyvio, here is my estimate of worldwide patients on this drug. Their clinical trial data numbers were small, which does not exude confidence there is non-zero risk of PML despite no reported cases. Although the actual # is likely larger considering therapy churn for other reasons, 30k vs. 3k patients is a bit more comforting. I know the FDA likely required them to state this risk due to a sister drug having this side effect even though there were no reported cases during the clinical trials.
It is still alarming to think about the risk of getting a terminal disease relative to living with IBD (daily struggles and the inherent risk of unmanaged GI inflammation that has its own cancer risk profile).

$250,000,000 Entyvio Q1 2017 global sales revenue (Takeda annual report)
$5,000 Estimated cost of drug per infusion

50,000 Compute total # of infusions performed in Q1 2017

Breakdown to distill # of patients:

5% My guess-estimate # of patients receiving 3 infusions in Q1-17 (1st dose)
15% My guess-estimate # of patients receiving 2 infusions in Q1-17 (2nd dose)
80% My guess-estimate # of patients receiving 1.5 infusions in Q1-17 (3rd and subsequent doses)

30,303 Estimated total patients currently on Entyvio (March 31, 2017) - Excludes patient therapy churn

It may also be hard to get numbers because of people with assistance programs and difficult in estimating infusion cost in other countries.

I subscribe to Medscape for any articles related to IBD, and than article of continued studies of the safety of Entyvio happened to come to my Inbox today. I will paste in the Conclusion, below. I think it looks relatively safe.

Vedolizumab, with its gut specific mode of action appeals as a safe alternative to systemic immunosuppression and reports from subsequent patient cohorts confirm the favourable safety profile described in the registration trials of almost 3000 patients. There are two areas that require further study: an early signal of increased risk of post-operative complications and the risk of infections in the paediatric population. Such data should not be over-interpreted: patients receiving VDZ soon after FDA approval are likely to have disease towards the severe end of the spectrum, often having failed oral immunomodulators and anti-TNF therapy. Further prospective data through registries are needed to properly appraise the risks. Although no comparative data is yet available, VDZ may offer a safe alternative to anti-TNF therapy and has an obvious role as the preferred immunosuppression in some groups with IBD who may benefit most from the lack of systemic immunosuppression, including patients predisposed to infection, current or past malignancy, or those at the extreme of age.