Multiple therapies but no cure yet for Covid-19

It is over six months now that the coronavirus pandemic has swept the world, leaving more than half a million people dead. There is still no cure against the virus that causes a disease called Covid-19. As such, antiobiotics do not help with viral infections, and some old antiviral drugs have been repurposed to treat patients suffering from Covid.

Researchers worldwide are testing various possible treatments that would help patients recover faster from the disease.

According to the Mayo Clinic, supportive care is aimed at relieving the symptoms and may include pain relievers (ibuprofen or acetaminophen), cough syrup or medication, rest and fluid intake.

The USFDA granted emergency use authorisation of antiviral drug remdesivir (developed by Gilead for Ebola) to treat severe Covid cases. Several corticosteroids, too, have been recommended for use like dexamethasone apart from supplemental oxygen or mechanical ventilation.

Immunosupressant drugs, too, are being tried to treat patients with Covid infection, that is, those who are developing an abnormal immune response against the virus. Doctors have prescribed drugs like Roche's Tocilizumab, which is used typically for rheumatoid arthritis (a painful condition where a patient's own immune system attacks the joints), to treat Covid patients.

The immune system of patients with Covid often go into an overdrive and produce an excess of immune signalling molecules called cytokines. This cytokine releases syndrome, often popularly known as the ‘cytokine storm’, leading to hyper inflammation. This, in turn, excerbates the breathing difficulties and may lead to acute respiratory distress syndrome (ARDS).

Drugs like Tocilizumab and Interferon alfa-2b act to supress the immune system response by blocking certain receptors called interleukin-6 (IL6). Interferon alfa-2b is under clinical trial for Covid treatment now.

Some common drugs are being used in India for treating Covid patients. They include:

Hydroxycholoroquine (HCQ)

HCQ is being used as a prophylactic (or preventive) for frontline medical workers, police etc. It is also approved as a treatment in mild cases with some caveats. US President Donald Trump touted the drug as a magical medicine for Covid, but several global trials have not found evidence to suggest proven benefits of HCQ. A strip of 15 tablets (200 mg tablets) costs around ~100.

Favipiravir

Oral antiviral drug that was approved for use in Japan for influenza patients recently got the regulator's nod in India for emergency use in patients with mild to moderate conditions. Glenmark conducted clinical trials for India and launched the drug for ~103 per tablet. Within a month of the launch, it slashed the prices to ~75 per tablet. Several Indian players, including Hyderabad's Dr Reddy's Laboratories, are in fray to launch this drug.

Remdesivir

Developed by Us-based Gilead Sciences for Ebola, the drug has been approved in India for hospital

use. It is an injectable drug and so far two companies have launched it — Hetero’s Covifor (~5,400 per dose) and Cipla's Cipremi (~4,000 per dose). Others like Zydus Cadila, Mylan and Dr. Reddy's are expected to launch it also. Clinical trials have shown that remdesivir helps to shorten the recovery time. It, however, does not reduce mortality.

Tocilizumab

This Roche drug that is marketed by Cipla in India is used in hospitals to treat severe Covid patients. It works to reduce the inflammation that happens when a patient's immune system reacts abnormally. The drug costs around ~40,500 for 400 mg dose (commonly prescribed too), ~20,200 for 200 mg and ~8,112 for 80 mg dose.

Itolizumab

Biocon's psoriasis (skin condition) drug is also an injectable for hospital use. The drug was launched in 2013 under the brand name Alzumab to treat plaque psoriasis. It is priced at ~7,950 per vial and most Covid patients would need four vials. The drug was approved on July 11 for restricted emergency use for treating moderate to severe Covid cases

Steroids

Indian clinical management protocol also allows use of steroids like Dexamethasone. This inexpensive steroid (~3 or so for a strip of 10 tablets and ~10 for a 4 mg injection) is effective in treating patients. Methylprennisolone is another steroid being used by doctors to handle moderate to severe Covid patients.

Heparin

A common anti-coagulant drug (that reduces blood clots from forming in the body) is used in treating Covid patients here. According to recent findings, Heparin can bind with the surface spike protein and potentially block the infection. Researchers at Rensselaer Polytechnic Institute in the US have said Heparin could effectively neutralise SARS-COV-2.

Convalescent plasma therapy

An experimental therapy in which blood plasma from patients who have recovered from Covid infection is collected and tranfusion is done to currently sick person. It gives the receiver a 'borrowed immunity' as the antibodies that a recovered person has are passed on to the sick person. This helps them fight the pathogen. Plasma banks have been already set up in some states.