A drug used for erectile dysfunction has the potential to treat critically ill Covid-19 patients, scientists say.
Aviptadil — branded as Invicorp in the UK but not yet marketed in America — has been fast-tracked into the next stage of clinical trials after promising results.
Almost 300 patients with moderate and severe bouts of coronavirus at five hospitals in the US will given an inhaled version of the drug.
Some 16 patients in the US came off ventilators or recovered from respiratory failure within four days of inhaling the drug, the drug’s manufacturers claim.
And doctors in Houston claim the drug helped one patient on the brink of death make a ‘rapid recovery’.
The drug is a synthetic form of a natural peptide in the body called VIP that protects lung cells from injury by reducing inflammation.
Brazilian researchers have also shown the peptide can block the coronavirus from entering cells and replicating.
Aviptadil is combined with another ingredient called phentolamine for the treatment of erectile dysfunction.
The two medications, when taken together, help blood flow in and out of the penis, causing it to stay firm.
The formula is injected directly into the tissue on the sides of the penis causing an erection around five minutes later.
Men can only get it on prescription, and once they are shown how to carry out the injection by a nurse they can do it themselves.
When the Covid-19 pandemic struck, US-Israeli company NeuroRx Inc partnered with Swiss drug firm Relief to develop the drug.
The firms today said they had been granted permission to progress trials of aviptadil for the prevention of respiratory failure in Covid-19 patients.
The first part of the phase two and three trial, expected to begin before September, will involve hospitalised severe Covid-19 patients.
If promising results are seen, the trial will expand to patients at home with mild and moderate Covid-19 in order to prevent the need for hospitalisation.
Aviptadil will be inhaled because it allows the medicine to reach deep into the lung tissue.
Half the patients will receive aviptadil while the other half, randomly selected, will be given a placebo drug and ‘maximal intensive care’.
Aviptadil has already been through clinical trials for ARDS — a life-threatening lung disease and known complication of Covid-19.
Relief says seven out of eight patients with severe ARDS on mechanical ventilation dramatically improved with doses of VIP.
Doctors from Houston Methodist Hospital revealed on August 1 that the drug helped a patient make a ‘rapid recovery’, with details reported on the website PrePrints.
The patient developed Covid-19 while being treated for rejection of a double lung transplant. He came off a ventilator within four days.
Similar results were seen in more than 15 patients treated under emergency use, Relief and NeuroRx reported.
X-rays showed they had a rapid improvement in blood oxygen, showing the lungs were working to pump oxygen around the body again.
But because only a very small amount of people have been treated with aviptadil, and the drug was not compared to a dummy drug, it cannot be said definitively that aviptadil actually improved the patients’ outcomes or if it was just chance.
The placebo-controlled trial across five US hospitals will prove whether or not that aviptadil is actually treating patients.
Some 70 per cent of the VIP in the body is bound to specific cells in the lungs, called the alveolar type two cell.
These cells are critical for the transmission of oxygen to the body, so without them, respiratory failure occurs.
The cells are targeted by coronavirus because they are coated with ACE-2 receptors, which serve as the doorway of entry for the virus to replicate.
The theory is that the synthetic VIP will bind to the lung cells and block SARS-CoV-2 — which causes Covid-19 — from doing the same.
Researchers in at the Oswaldo Cruz Institute, Rio de Janeiro, found aviptadil blocked replication of the virus in human lung cells in laboratory conditions.
The same experts, writing their findings in a pre-print paper, also said survivors who were hooked up to ventilators had more VIP in their blood than those who died.
NeuroRx CEO Jonathan Javitt said: ‘No other antiviral agent has demonstrated rapid recovery from viral infection and demonstrated lab inhibition of viral replication.’
VIP has been shown to have anti-inflammatory properties in animals. Inflammation is a known complication of Covid-19 with fatal consequences.
VIP prevents production of inflammatory cytokines — which in high levels can cause lung injury.
Cytokines are a proteins in the body that give signals between cells. They play an important role in normal immune responses.
When the body releases too many inflammatory-provoking cytokines in one go, it’s called a ‘cytokine storm’.
It is thought to be a major factor behind lung damage, catastrophic organ failure and death in some coronavirus patients.
Just two medicines — remdesivir and dexamethasone — have been shown to reduce the risk of death in patients already hospitalised.
Dexamethasone saves up to 35 per cent of Covid-19 patients relying on ventilators – the most dangerously ill, researchers led by Oxford University showed.
Remdesivir — an experimental drug originally designed to treat Ebola — has already been approved to treat Covid-19 patients in the UK since May.
But the study results for remdesivir are not as conclusive as dexamethasone.