I can't think very long about injunctive relief without hearing that the Schoolhouse Rock classic "Injunction Junction, What's Your Function?" If you weren't blessed to get to hear these classic the first time around, take a few minutes to listen. It doesn't rise to the heights of the episodes on the Preamble (which we used to sing to Professor Jordan in Policy Development class in graduate school whenever she said the words "The Constitution..." (okay, try to picture Barbara Jordan saying "The Constitution ..." with that voice of hers and a dozen students starting singing "We the Peo-puull, in ooorder to form a more Perrfect Yewn-Yun..." Trust me, it was just the best. Ever.
Or the kingfish "I'm Just a Bill (Sittin' on Capitol Hill)" (hysterically parodied on SNL recently by comparing it to an executive order) but it's still up there, as ear worms go.
The function of pretrial injunctions is, candidly, not much in most patent cases because the standard is so high. In one conference on the issue I heard a judge analogize the likelihood of one being granted to that of the sun rising in the west. But a couple of recent opinions granting injunctions underscore that they still can still play a role in the right cases.
In the Mylan v. Aurobindo Pharma case, Judge Payne granted the plaintiff's motion, finding that it had established the four factors of (1) likelihood of success on the merits, (2) likelihood of irreparable harm; (3) balance of equities tipping in its favor; and (4) injunction is in the public interest. But it took a while to get there - after eight pages of preliminaries, Judge Payne spent 36 pages on likelihood of success, analyzing claim construction, infringement and the asserted defensive issues (invalidity, etc.), then another five pages on the three other factors before concluding that an injunction barring the defendant's sale of isosulfan blue formulations used in mapping the lymphatic system was appropriate. (I knew I was seeing a gap in the shelving next to dandruff shampoos. Now I know why).
Similarly, in Tinnus v. Telebrands, Judge Love referenced an earlier-issued injunction involving a manufacturer of an accused product "Battle Balloons" and considered the effect of extending the injunction to the remaining stock of these play aids held by various retailers (estimated at 200,000 units). The Court concluded that the injunction should be extended to existing stock at the various retailers.
So they do get issued. And these two opinions provide a good summary of caselaw on when.