TGA approves new COVID-19 treatment
<p><span style="font-weight: 400;">The Therapeutic Goods Administration (TGA) has granted provisional approval for a new oral treatment for COVID-19, which is due to arrive in Australia within weeks.</span></p>
<p><span style="font-weight: 400;">The new treatment, called PAXLOVID, was developed by Pfizer to treat symptoms of COVID-19 and reduce the risk of hospitalisation or severe illness.</span></p>
<p><span style="font-weight: 400;">The TGA has approved the treatment for adults over the age of 18 who don’t require supplemental oxygen and are at a higher risk of needing to be treated in hospital.</span></p>
<p><span style="font-weight: 400;">Dr Krishan Thiru, Pfizer Australia’s Medical Director, spoke to </span><span style="font-weight: 400;"><em>OverSixty</em> </span><span style="font-weight: 400;">about who the provisional approval is meant for and how the treatment works.</span></p>
<p><span style="font-weight: 400;">“This is an oral, take-at-home treatment that’s designed to help people who are already diagnosed with COVID-19 who are at higher risk of deterioration,” Dr Thiru explains.</span></p>
<p><span style="font-weight: 400;">“This could include people who are aged over 60, people who have other risk factors such as high blood pressure, diabetes, (people who are) smokers or they’re overweight, chronic heart, lung or kidney disease, people who are immunocompromised, or people who have an active cancer.</span></p>
<p><span style="font-weight: 400;">“So it’s designed to treat those people who still have mild disease, so they’ve just been diagnosed, to prevent their risk of deterioration.”</span></p>
<p><strong>What is PAXLOVID?</strong></p>
<p><span style="font-weight: 400;">PAXLOVID consists of two kinds of tablets: nirmatrelvir tablets and ritonavir tablets. Nirmatrelvir - which was developed in Pfizer laboratories - does the work of stopping the virus from spreading through the body, while ritonavir - which is also used in treatments for HIV - slows down the breakdown of nirmatrelvir so that it can have an effect for a longer period of time.</span></p>
<p><img style="width: 0px; height:0px;" src="https://oversixtydev.blob.core.windows.net/media/7847041/pax1.jpg" alt="" data-udi="umb://media/aaa8dba6758145bcb2bba296c5bdfe57" /></p>
<p><em><span style="font-weight: 400;">A new treatment for COVID-19 uses two pills to stop the virus from replicating and spreading through the body. Image: Supplied</span></em></p>
<p><span style="font-weight: 400;">“(PAXLOVID) is an antiviral. So how it works is that it inhibits one of the key enzymes that the SARS coronavirus that causes COVID-19 requires in order to start replicating,” Dr Thiru explains. “So it slows down the ability of the virus to spread within the body and then allows the body to then utilise its own immune defences to overcome the virus.”</span></p>
<p><span style="font-weight: 400;">Dr Thiru says stopping the virus and giving the body a chance to defend itself reduces a person’s chances of becoming severely ill.</span></p>
<p><span style="font-weight: 400;">Because the treatment needs to start within five days of symptoms occurring, Dr Thiru says PAXLOVID is “essentially a preventative treatment”.</span></p>
<p><span style="font-weight: 400;">The drug that would eventually become nirmatrelvir was </span><a rel="noopener" href="https://cen.acs.org/pharmaceuticals/drug-discovery/How-Pfizer-scientists-transformed-an-old-drug-lead-into-a-COVID-19-antiviral/100/i3" target="_blank"><span style="font-weight: 400;">first developed</span></a><span style="font-weight: 400;"> in July 2020, with encouraging results from studies in rats emerging in September.</span></p>
<p><span style="font-weight: 400;">In July of the following year, the first of three clinical trials of PAXLOVID began. The EPIC-HR (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients) trial recruited about 2200 people with COVID-19 who weren’t in hospital but at risk of severe illness. About half were given PAXLOVID, while the other half received a placebo.</span></p>
<p><span style="font-weight: 400;">As for the demographics of people involved, Dr Thiru says 49 percent were women, the median age was 45 years, and that different ethnic groups were also represented.</span></p>
<p><span style="font-weight: 400;">“The study was conducted in North America, Central America, South America, in Asia, in Europe, and in South Africa as well,” he says.</span></p>
<p><span style="font-weight: 400;">The trial found that PAXLOVID reduced a person’s likelihood of hospitalisation or severe illness by 89 percent when they were treated within three days of symptoms appearing.</span></p>
<p><span style="font-weight: 400;">Out of the 697 people receiving PAXLOVID, only five were hospitalised in comparison to 44 out of the 682 people in the control group.</span></p>
<p><span style="font-weight: 400;">For those treated within five days of symptoms starting, the trial found that PAXLOVID reduced risks by 88 percent in comparison to the placebo.</span></p>
<p><span style="font-weight: 400;">Though the results were consistent across the different age groups, Dr Thiru says there was a “suggestion” that the treatment may have a larger benefit for those aged over 60.</span></p>
<p><span style="font-weight: 400;">“It wouldn’t be surprising if older people were to benefit,” he says. “And that’s because… the chance of people deteriorating is higher in that age group. So a clinical trial is more likely to show a difference, if indeed there is any, between the placebo group and the PAXLOVID group.”</span></p>
<p><span style="font-weight: 400;">However, he stresses that it’s too early to draw conclusions about findings related to particular age groups or even between men and women.</span></p>
<p><span style="font-weight: 400;">“As this medicine becomes more used in the real world, more data will be collected from all of the countries that it’s been used in,” he says. “And that may help describe which particular subgroups of patients benefit more.</span></p>
<p><span style="font-weight: 400;">“But, obviously, we need to wait until those results become available.”</span></p>
<p><strong>How does PAXLOVID compare to vaccines?</strong></p>
<p><span style="font-weight: 400;">Unlike vaccines and other provisionally-approved treatments - such as the injectable combination treatment Ronapreve - Dr Thiru says PAXLOVID doesn’t target the virus’ spike protein in order to disrupt it.</span></p>
<p><span style="font-weight: 400;">“So it works once the virus is already inside the body or inside the cell and replicating,” Dr Thiru says. “So it doesn’t target the spike protein.”</span></p>
<p><span style="font-weight: 400;">This also means that mutations in the virus may have less of an impact on the treatment’s effectiveness in comparison to vaccines.</span></p>
<p><span style="font-weight: 400;">The approval comes as the Australian government has secured 500,000 treatment courses this year, with supplies due to start coming in within weeks.</span></p>
<p><span style="font-weight: 400;">“We supply (PAXLOVID) to the government, and then they distribute that,” Dr Thiru says, explaining that the treatments will then be distributed via the national medicines stockpile to the states, who will then distribute it to individuals.</span></p>
<p><span style="font-weight: 400;">Though Australians continue to face difficulties accessing rapid antigen tests (RATs) and PCR testing sites remain overwhelmed, the new treatment relies on identifying COVID-19 as soon as symptoms appear.</span></p>
<p><span style="font-weight: 400;">Since COVID-19 </span><a href="https://www.cdc.gov/flu/symptoms/flu-vs-covid19.htm"><span style="font-weight: 400;">shares some symptoms</span></a><span style="font-weight: 400;"> with the common cold and flu - think fever, cough, sore throat, runny nose, and body aches - Dr Thiru says it’s best to get tested as soon as symptoms appear in case you need to take PAXLOVID.</span></p>
<p><span style="font-weight: 400;">“As soon as (people) experience any symptoms that could possibly be COVID-19, go and get tested as soon as possible, because time becomes of the urgency because if it does turn out to be COVID-19, then you need to have initiated (the treatment) within five days of when your symptoms first commence,” he says.</span></p>
<p><span style="font-weight: 400;">“If it’s anything unusual or out of the ordinary for you, and it is one of the common symptoms described for COVID-19, we’d urge you to go out and get tested as quickly as possible.”</span></p>
<p><em><span style="font-weight: 400;">Image: Getty Images</span></em></p>
