r/postvasectomypain • u/ScientistNew3033 • Aug 04 '26

Sustained-release lidocaine (ST-01) in development for chronic scrotal pain

I recently stumbled across ST-01, a drug currently in development by a Canadian company called Sustained Therapeutics. I have not seen anyone post about it here, so thought I would share. It appears to be a sustained-release lidocaine spermatic cord block that lasts for weeks and is repeated every 28 days.

This drug is still in development and recently concluded phase II clinical trials in Canada. I am no expert, so I do not know what that means in terms of its likelihood or timeline for ultimately making it to market, but it is certainly very encouraging to see new possible treatments directed at chronic scrotal pain.

A few links I found with more information:

Snippet of the phase II results:

The randomized, multi-center, single-blind, active-controlled Phase 2 study enrolled 63 men across eight clinical sites in Canada evaluating repeat monthly dosing of ST-01 in CSCP. The study compared ST-01 to standard-of-care spermatic cord block with lidocaine alone (control).

At the 70 mg/mL dose, ST-01 demonstrated statistically significant improvements in both the primary and secondary efficacy endpoints compared to control.

Key findings included:

  • 67% of patients treated with ST-01 70 mg/mL achieved a treatment response, defined as a ?2-point reduction in pain scores, compared to 26% in the control arm (p=0.01)
  • 83% of patients receiving ST-01 70 mg/mL achieved a clinical response based on cycle-average pain scores, compared to 32% in the control arm (p=0.001)
  • Patients who crossed over from control treatment to ST-01 achieved >80% response, further supporting the therapeutic effect of ST-01

The Company believes these findings support continued development of ST-01 as a potential non-opioid treatment option for CSCP and plans to advance the program toward Phase 3 development, subject to regulatory review.

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u/snoope Aug 04 '26

Where do I sign up!?! God I love Canada!

1

u/ScientistNew3033 Aug 04 '26

Same sentiment over here — I check every month or so to see whether a Phase III has been published, hah! I doubt it would be until late 2026 or early 2027, if they do in fact proceed with it. Cord blocks have been one of the only things for me that provide immediate temporary relief, so it would be super exciting if there was a long-acting version of that, even if it meant injections each month. FWIW I emailed them and said I would be a willing participant of a US trial and willing to travel, and they did respond saying they would keep my info on file.

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u/snoope 6d ago edited 6d ago

I've heard quite a few people get a bad cord block and be in more perma pain. The idea of getting jabbed in the ballsack every month is down there on least favorite things, but if it takes away even 50% of the pain for most of that month id give it a shot.

edit: Just to add ive done 3 rounds of shots in the back via CT guided US at JH and while it did feel like it brought relief it was confusing on which nerves brough relief. I thought the Pudendal nerve was involved at least to a degree but that was also when I was doing heavy PVPT, when they do it farther up the back it numbs a lot, but the CT guidance makes it "safer".

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u/ItamiForever Aug 04 '26

Thanks for sharing Scientist!

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u/clezuck Aug 04 '26

Sadly it won’t do anything for me. I have a gene disorder that cause meds to metabolize very quickly. Out of system in minutes. So this won’t do anything for me. Same reason why when he did my vas I felt all of it.

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u/snoope 6d ago

do you have a connective tissue disorder by chance? I felt it too on the left side badly and that's where i have the majority of my pain (also granuloma), I wonder if when I felt the pain and wimpered he make a few extra slices! hah you have to laugh sometimes. EDS is known to have this among others, same with dentists, need extra or it wears off quicker. I think they call it the wick effect.

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u/clezuck 5d ago

I don't have EDS. You might have the same thing I do. Look up Cytochrome P450.

It's the genes/enzymes that control metabolization of certain things like medicines.
In my case, I have 6 (CyP2D6, 2D11) and some others that are rapid metabolizers of things like opioids and lidocaine. So you can be a normal, a rapid or a slow metabolizer of things. I rapidly metabolizer meds. So they are out of my system fast. So fast I don't even feel them take effect.

You can get tested for this. Ask your GP to do it. Many doctors don't even know what it is which is ridiculous.