No Biomarker Yet Predicts Inebilizumab Response: Richard Nowak, MD, MS

Myasthenia gravis (MG) specialists still can't tell ahead of time which patients will respond well to inebilizumab, or to any other approved therapy, according to Richard Nowak, MD, MS, associate professor of neurology at Yale School of Medicine and global principal investigator of the MINT trial.

No Way to Predict Response

The clinical trial data show the medication is safe and effective for patients with generalized MG who are either acetylcholine receptor (AChR)– or muscle-specific kinase (MuSK) antibody–positive, Nowak said. But knowing a drug works for a population is different from knowing it will work for an individual patient. What clinicians do have is a rationale tied to mechanism because inebilizumab directly targets the cells that produce autoantibodies, so the likelihood of benefit is high but not guaranteed. In practice, Nowak said he would consider the drug for any patient with matching antibody status who isn't doing well and needs a new option, even without a way to predict the response in advance.

"We don't have, for any of the available therapies, including inebilizumab, predictive treatment response markers that we know ahead of time what treatment a patient is going to respond to or have a partial response or no response to," Nowak said.

A Case for Preventing Costly Exacerbations

Nowak also pointed to a benefit that extends beyond the individual patient, health care resource utilization. Disease exacerbations typically require hospitalization, and the rescue therapies that follow, intravenous immunoglobulin or plasmapheresis, add further cost and burden to the health system. The same reasoning applies directly to patients, who avoid hospitalization, missed work, and burdensome procedures when exacerbations are prevented. Looking ahead, Nowak said the data published so far cover only the randomized controlled period, with up to 3 additional years of open-label extension data still to come, likely within the next year, that should add to what's understood about inebilizumab's long-term efficacy, safety, and durability.

"If we can mitigate the risk of exacerbation, mitigate risk then of hospitalization, and mitigate the risk of rescue therapy use, that's not only beneficial to the health system but also reduces the cost spent in caring for patients that aren't doing well," Nowak concluded.