(Bloomberg) -- Australian biotech group CSL Ltd. has begun enrolling US patients in a late-stage study to test a self-administered antibody-based therapy for a blood circulation issue that’s one of the most common and disabling symptoms of long Covid.
The randomized control trial will assess whether Hizentra, a subcutaneous immunoglobulin treatment, can alleviate symptoms of postural orthostatic tachycardia syndrome, or POTS — a disorder of the autonomic nervous system with no approved therapies. The US Food and Drug Administration has granted the trial a “fast track” designation, recognizing its potential to address a significant unmet need, Melbourne-based CSL said Friday.
POTS is marked by sudden increases in heart rate, dizziness, fatigue and other symptoms when moving from a seated or lying position to standing. As of the end of 2023, over 400 million people globally are estimated to have developed long Covid, with studies indicating that around 2-14% of Covid survivors develop POTS, and another 9-61% experience POTS-like symptoms within six to eight months.
“The incidence of POTS has risen dramatically with the Covid pandemic,” Marie-Pierre Hellio, CSL’s senior vice president of strategic development, told analysts at an R&D meeting earlier this week. “Symptoms can leave patients unable to work, and even partially bed bound.”
While the underlying causes aren’t fully understood, immune system dysregulation, including the production of autoantibodies, is believed to play a role in post-Covid POTS. Immunoglobulins possess various immunomodulatory properties that may help influence these immune pathways.
“Subcutaneous immunoglobulin is particularly interesting,” said Akiko Iwasaki, director of Yale’s Center for Infection & Immunity. Previous studies with intravenous immunoglobulin, or IVIG, have raised concerns that symptom improvements might be due to large saline infusions in the placebo group, but subcutaneous immunoglobulin bypasses this issue. The CSL-sponsored trial also uses a control injection of the same volume to ensure accuracy, she said.
Animal studies from Iwasaki’s lab have shown that immunoglobulin from long Covid patients reporting new pain symptoms following infection can transfer that pain to recipient mice, suggesting that certain autoantibodies may target pain neurons. If true, healthy human immunoglobulin could potentially block the receptors responsible for this pain, she said.
Participants in the study will be randomized to receive subcutaneous infusions of Hizentra or a placebo for 24 weeks, followed by an open-label treatment phase. The primary goal is to measure the proportion of participants who no longer meet the diagnostic criteria for post-Covid POTS.
The phase III study involving around 177 participants is slated to conclude in September 2027.
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