Medicines for stomach acid reduce the effectiveness of a cancer medicine

When taken with gastric reflux medication, treatment used in advanced kidney cancer and some sarcomas is less effective. To the point of reducing patients' survival time.

Medicines for stomach acid reduce the effectiveness of some cancer treatments until the survival time of patients taking them is reduced. This is shown in a study published in the magazine on Thursday Clinical cancer research by a team from the Gustave Roussy Institute (Villejuif, Val-de-Marne). These anti-acidic drugs are currently widely used in oncology.

However, not all patients are affected by this contraindication. Only in patients with metastatic soft tissue sarcoma means "concomitant use of a drug that reduces gastric acidity and pazopanib significantly reduces progression-free survival and overall survival". Pazopanib is an anticancer medicine marketed under the trade name Votrient and is indicated for the treatment of advanced kidney cancer and certain soft tissue sarcomas.

Survival reduced by 4 months

To arrive at this conclusion, the authors analyzed data from 333 patients who participated in two clinical studies conducted by the British pharmaceutical group GlaxoSmithKline to request approval of Votrient for the treatment of sarcomas in the market.

As a result, the median progression-free survival time for cancer in patients who had an antacid for at least 80% of their treatment with pazopanib was only 2.8 months, compared with 4.6 months. in those who have not used treatment with antacids. And median overall survival was 8 months for those with acid-free drugs for at least 80% of the duration of treatment with pazopanib, compared with 12.6 months for those who did not use it.

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Less good absorption of the treatment

Previous studies have previously shown that these acid treatments, such as omeprazole (Mopral), esomeprazole (Inexium) or ranitidine (Azantac), lower the levels of pazopanib in the blood of patients with solid tumors. the Gustave Roussy Institute.

Indeed, "pazopanib tablets taken orally have to dissolve in an acidic environment, ie in the stomach," says Dr. Mir, medical oncologist and pharmacologist at the Gustave Institute Roussy. "Since the main function of antacid treatment is to reduce the acidity of the stomach, these treatments can reduce the absorption of pazopanib."

According to the institute, up to 50% of people who undergo cancer treatment also take this type of medicine. In France, some of these molecules are for sale. According to Dr. Mir, also co-author of the study, "the results of this analysis should encourage oncologists to change the treatment of their patients", especially because "patients often use antacids to relieve". abdominal pain that is not always directly related to the acidity of the stomach "and therefore" could fall back on another treatment ".

In view of these results, "doctors and pharmacists should follow patients who take these two treatments at the same time, in particular," says the oncologist.

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