It’s always a good day when a new treatment, especially one for lung cancer, becomes available. It’s even better when the drug trial was stopped early because the results were so clear. Though overshadowed in the headlines because the FDA approved it and gave emergency use authorization to Moderna’s Covid-19 vaccine on the same day, Tagrisso is the first adjuvant ( a secondary or followup ) treatment approved for non-small cell lung cancer. Also called osimertinib, the drug had previously been approved as a stand-alone treatment for metastatic lung cancer -- disease already affecting other parts of the body.

Background on lung cancer

Lung cancer is both the most common type of cancer and the leading cause of cancer-related deaths worldwide. Non-small-cell lung cancer (NSCLC) is the most common type, making up 80% or so of US cases. Lung cancer kills more than 145,000 Americans every year.

Lung cancer is often, but not always, caused by smoking. Mayo Clinic lists symptoms as including persistent cough, coughing up blood, shortness of breath, chest pain, hoarseness, unintended weight loss, and bone or head pain. The main treatments are surgery, radiation therapy and chemotherapy.

What is Tagrisso aka osimertinib?

First, a brief explanation of a protein called epidermal growth factor receptor, or EGFR. In a cell that functions normally, EGFR plays a major role in ensuring that the cell does what cells are supposed to do: properly react to their environment, (for example, more muscle is required because of exercise); grow as much as needed; then divide -- and continue making these steps, with precision timing. These steps ensure cell survival.

But sometimes the EGFR gene gets damaged. When that happens, the cell will likely get damaged too, throwing the cell division process way off, as if an on-button has become stuck.

The gene can be damaged in various ways, thereby creating various mutations. Finding the right mutation in a cancer patient, and then treating the patient with a treatment precisely designed for that mutation is called precision medicine. Osimertinib treats two of the most common mutations.

Osimertinib comes as a pill that is taken once daily. The drug works by targeting and blocking the mutated EGFR genes, preventing them from growing and spreading. According to the FDA press release, roughly 20% of NSCLC patients have EGFR mutations and 30% of those patients have had tumors surgically removed. That means that more than 10,000 NSCLC cancer patients could benefit from using osimertinib once the tumor is removed.

The study

Osimertinib was tested in 682 patients in a randomized, placebo-controlled, double-blind, (neither patients nor physicians knew which patients had received the placebo pill or the drug pill) trial. These patients were in the early stage of lung cancer. Some had errors in their genetic material that disrupted proper cell division, or were positive for another EGFR mutation. All had undergone surgery.

About half of the patients received the osimertinib, the other a placebo. If they had been receiving chemotherapy after surgery, this was not stopped during the trial. The trial researchers wanted to compare how much time passed before the cancer returned or if a patient was disease-free. Patients who received the durg had an 80% decrease in disease recurrence compared to those in the placebo group.

With other treatments, more than half of early-stage, NSCLC patients will experience a recurrence of their cancer.

Common side effects of osimertinib include diarrhea, rash, muscle pain, skin dryness and inflammation, soreness in the mouth, fatigue and cough. There have also been reports of more severe lung, heart, and cornea issues; treatment should cease immediately. The drug’s approval was given to AstraZeneca.

The approval

Osimertinib had previously been approved in 2018 as a primary treatment for people with metastasized NSCLC under specific circumstances determined by genetic testing. The new adjuvant approval will allow cancer patients earlier, preventive access.

"Today’s approval of Tagrisso demonstrates how additional research on therapies approved in later stages of cancer can eventually improve treatment options for patients in earlier stages,” said Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research, in a press release. “With this approval, patients may be treated with this targeted therapy in an earlier and potentially more curative stage of non-small cell lung cancer.