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Aug 13, 2025, 07:01

Murali Janakiram: The Toxicity Profile of GPRC5D Bispecific Antibody Talquetamab

Murali Janakiram, Associate Professor at the Division of Hematological Malignancies at City of Hope, shared a post on X about a paper he co-authored with colleagues published in Blood Cancer Journal:

“We want to share this important toxicity profile of GPRC5D BisAb- Talquetamab.

GPRC5D Bispecific antibody talquetamab-induced dizziness-ataxia syndrome, clinical presentation and management- a case series.

We know that GPRC5D is possibly expressed in the inferior olivary nucleus of the cerebellum. This has been previously reported in GPRC5D CART as a cerebellar syndrome.

Here we report 4 patients who presented with dizziness and ataxia with no cerebellar signs initially and extensive inv. r/o other causes

2 patients were not rechallenged with talq
1 patient, the talq was held and rechallenged at a lower dose and increased frequency with no recurrence of symptoms
1 patient continued talq with recurrence of symptoms with doses and later developed cerebellar syndrome

Why call it dizziness-ataxia syndrome?

This is the first presentation
Calling it a cerebellar syndrome can make clinicians wait as there are no obvious cerebellar signs at initial presentation
Waiting can lead to worsening and permanent cerebellar signs
Hence till we know pathophys. we humbly request to call it dizziness ataxia syndrome.
It has mostly occurred early within the first 60 days
We think it is a dose dependent toxicity
All clinical trials with GPRC5D targeting agents should report this and whether this syndrome was present or not
Early discontinuation is key

Thanks to all co-authors.”

We are collecting more information on this toxicity, and please reach out.”

Rahul Banerjee, Assistant Professor at Fred Hutchinson Cancer Center and at the University of Washington, shared this post, adding:

“It goes by many names: OSN, non-ICANS neurotox, ‘dizziness-ataxia syndrome’ in Blood Cancer Journal paper below (which I love as a name).

Importantly, it can happen with both GPRC5D bsAbs and CAR-T.

n=4, clear Sx recurrence after re-challenge. Thankfully, stopping tal seems to work!”

Title: GPRC5D Bispecific antibody talquetamab-induced dizziness-ataxia syndrome, clinical presentation and management- a case series

Authors: Murali Janakiram, Lawrence Liu, Scott Goldsmith, Azra Borogovac, Sarah Lee, Nitya Nathwani, Michael Rosenzweig, Firoozeh Sahebi, Myo Htut

You can read the Full Article on Blood Cancer Journal.

Murali Janakiram: The Toxicity Profile of GPRC5D Bispecific Antibody Talquetamab

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Azra Borogovac Blood Cancer Journal cancer dizziness-ataxia syndrome Firoozeh Sahebi Lawrence Liu Michael Rosenzweig Murali Janakiram Myo Htut Nitya Nathwani OncoDaily Oncology Rahul Banerjee Sarah Lee Scott Goldsmith Talquetamab

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