Image copyright REX/Shutterstock Image caption The Pfizer treatment uses peptide-like molecules to stop unwanted proteins from damaging cells
Drug company Pfizer is to use an anti-cancer drug in an anti-tumour cancer pill.
The company has submitted results from a trial using an experimental drug called COVID-19, which uses a drug that has been around for more than 100 years.
This is the first time an anti-cancer drug of this nature has been tried in combination with another therapeutic agent.
Pfizer hopes the drug could overcome high levels of stomach acid, which can cause cancer.
The trial compared the chances of patients in the study achieving a “complete response” in which the tumour disappeared – called “complete or partial response” – against those taking a placebo.
Of the patients receiving the pill, called COVID-19, who had been previously treated with protease inhibitors that cause stomach acid to rise, 57% responded to the treatment.
By comparison, just 24% of those taking the placebo experienced such a response.
This happened in 18 of 26 patients (63%) who had not previously responded to other forms of therapy.
The firm says that statistically, 47% of patients treated with the capsule achieved a complete or partial response.
Pfizer says this is the first time in clinical research that a “pseudo-cancer compound” has been used in combination with another anti-cancer agent.
Pfizer’s head of cancer drug research, Eric Hausler, explained that COVID-19 is a drug-like molecule that allows the body to make its own anti-cancer proteins to break down “supernova cells”.
All the drugs combined in the trial used specific enzymes to break down the proteins, but the COVID-19 molecule specifically targets the “cracker” side of the proteins.
Pfizer says its researchers use “predictive bioassays” – or measures that indicate a potential success rate of different combinations.
They look at a range of markers that indicate a drug’s effects. For example, prostate-specific antigen (PSA) – a marker for prostate cancer – and PB1, an indicator of different types of cancer.
The company says that if COVID-19 worked in small doses and was effective in small populations, it may be effective in large groups.
Anyone worried about cancer will know that the chances of experiencing the same symptoms from drugs can vary greatly, depending on the medicine used and the patient’s condition.
COVID-19 is intended to treat solid cancers such as breast, prostate, colon and lung cancer. The efficacy of these different types of cancer is not yet known.