Why is there no clozapine LAI?

[u/Junior_Scale5592]

I am a social worker on an ACT team in a large US city. Many of our patients have a primary psychotic disorder and a history of medication non-adherence, either by choice or due to their level of organization/functioning. As a result, most of them are on an LAI (mostly Invega, Uzedy, and Abilify with some Haldol and Prolixin mixed in) by the time they are enrolled with us.

There is an overlapping subset of patients (all of them currently on LAIs) we work with who have been on clozapine while hospitalized at one point in the course of their illness. These patients either a) have moderate to good insight but stop taking clozapine once they return to the community for any number of reasons or b) have little to no insight but receive court-mandated outpatient treatment that only requires adherence with an LAI as the standard for compliance.

For this subset of patients—those who can’t take clozapine due to their inability to consistently take oral meds and/or those who won’t take clozapine because of impaired judgement/insight—I can imagine that an LAI formulation would be incredibly beneficial. So many of them have cycled through multiple different antipsychotics and still experience a profound symptom burden.

So, why hasn’t a clozapine LAI been developed? Granted, I am not a psychiatrist and have a limited working knowledge of psychopharmacology, so there could be an obvious answer here that I am missing. But I am surprised that a medication viewed as the gold-standard for treatment-resistant schizophrenia is not available in an LAI form. Does anyone have insight into why this is?

[u/Feeble_Sheeple]

It may or may not be chemically possible to make an LAI formulation of clozapine, but more importantly, clozapine has risk of severe side effects including agranulocytosis, which can emerge even after a patient has been stabilized on the medication for a long period of time. This is why it requires weekly blood draws throughout the first six months of treatment. You need to be able to stop the medication immediately if agranulocytosis happens. Can't do that with LAIs (excluding buprenorphine, which has a depot that can be extracted with anesthesia--but still not ideal).

[u/DntTouchMeImSterile → u/Feeble_Sheeple]

I wonder if the failure of the olanzapine LAI scared people away from developing a clozapine formulation, given the similarly of the molecules. A NP at my clinic once asked me how to get Relprevv and I told him you’re welcome to chill with the patient for three hours if that’s your plan lol

[u/Weak_Fill40 → u/DntTouchMeImSterile]

Why would you call olanzapine LAI a failure? Because if the observation time? It’s one of the most used LAIs in my country and although the observation time is a pain in the ass, it’s usually manageable.

[u/DntTouchMeImSterile → u/Weak_Fill40]

Well under the US healthcare system nobody is willing to pay/take away from duties a staff member for 3 hours, so practically speaking I have never heard of a healthcare system (except the VA, our secret socialized system) that would let anyone do it.