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Explained: What is RLF-100 or Aviptadil, the 1970 drug being explored for Covid-19 treatment

Preliminary studies have shown that the drug RLF-100 protects alveolar type II cells that are responsible for oxygen exchange in lungs.

Written by Tabassum Barnagarwala , Edited by Explained Desk | Mumbai |
Updated: August 17, 2020 11:36:00 am
RLF-100 is not a new finding. It was discovered in 1970 by Dr Sami Said, a pulmonary medicine specialist. At a testing centre in Pune. Express Photo by Ashish Kale

An old drug formulation — RLF-100 — is being probed to treat Covid-19 patients after initial studies have shown that the drug is able to halt SARS-CoV-2 virus replication in lungs. In Mumbai, doctors have begun prescribing this drug although it is not available in India.

What does RLF-100 do?

RLF-100, also called Aviptadil, is a formulation of synthetic human Vasoactive Intestinal Polypeptide (VIP). VIP is released throughout the body, but remains mostly concentrated in lungs. It is produced by immune cells and nerve endings and acts as a neurotransmitter. It helps improve muscle activity and blood flow in gastrointestinal tract.

But it also plays another important function. Studies have shown VIP has anti-inflammatory and anti-cytokine activity properties. Preliminary studies have shown this protects alveolar type II cells that are responsible for oxygen exchange in lungs. Since coronavirus attacks lungs and the alveolar cells, the drug may be helpful in preventing SARS-CoV-2 onslaught in alveolar cell and limit damage in lung.

Houston Methodist Hospital was first to report recovery in a 54-year-old man who developed Covid-19 and became critical. The man had undergone a double lung transplant and later contracted Covid-19 infection. Doctors administered RLF-100 under emergency use and the patient could be weaned off ventilator in four days. “He received three infusions of RLF-100 under an FDA-approved emergency use IND (Investigational New Drug). Within 24 hours of the third infusion, substantial improvement in oxygen saturation and radiographic improvement in characteristic COVID-19 pneumonitis was noted. He was discharged from intensive care at that point and returned home at 1 week on room air,” a multi-author article by doctors stated. This article is however not yet peer reviewed.

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The clinical trial

RLF-100 has been granted “Orphan Drug Designation” by the US Food and Drug Administration (FDA) for Acute Respiratory Distress Syndrome and chronic lung diseases, drug maker NeuroRx said. On June 8, NeuroRx and Relief Therapeutics announced a phase 2/3 clinical trial to treat critical Covid-19 patients. The trial will have 144 participants. The drug will be targeted on those requiring high flow nasal oxygen, and those on non-invasive or invasive ventilator support. Doses for three successive days will be given to patients.

In a press statement earlier this month, CEO of NeuroRx Prof Jonathan Javitt said, “We are conducting placebo-controlled trials to see whether the observations made in the case-control and open-label studies will be confirmed for less ill patients with COVID-19-related respiratory failure. Our independent Data Monitoring Committee will be conducting an interim analysis of these data later this month.”

RLF-100 is not a new finding. It was discovered in 1970 by Dr Sami Said, a pulmonary medicine specialist. In 2001, US FDA gave RLF-100 an orphan drug designation to treat acute respiratory distress syndrome, and in 2006 for acute lung injury. US FDA also granted investigational new drug (IND) licenses for human trials of Aviptadil. But it has not shown significant progress in those trials in treating lung diseases.

Current use in Covid-19 treatment

There are still no well-designed clinical trials that have found optimistic findings for RLF-100 and research into its use to treat Covid-19 is in nascent stages. The manufacturer claims rapid clearance of pneumonia and improvement in oxygen levels in patients this drug was used on emergency basis.

In Mumbai, Breach Candy Hospital has prescribed this drug to a critically ill patient. The drug is currently not available in India. Kin of patient are trying to procure it from USA, treating doctors said.

Dr Rahul Pandit, intensivist in Fortis hospital, however warned. “There is very little known. For us to prescribe a drug, we need to wait for scientific evidence,” he said.

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