Tagrisso, known scientifically as osimertinib, is a targeted therapy medication. It is prescribed for patients diagnosed with non-small cell lung cancer (NSCLC) that is characterized by a specific alteration in the epidermal growth factor receptor (EGFR) gene. This type of medication works by specifically targeting and blocking the signals from the mutated EGFR protein that tell cancer cells to grow and divide. Tagrisso can slow or stop the progression of the cancer. The treatment is designed for particular genetic profiles, making it a form of precision medicine.
Understanding Tagrisso Treatment Duration
A common question for patients starting this therapy revolves around how long it can remain effective. Rather than focusing on individual outlier cases, clinical trial data provides a clearer picture of treatment duration. The FLAURA clinical trial offered significant insights into this question for patients receiving Tagrisso as their initial treatment.
The results from the FLAURA trial are often discussed in terms of Progression-Free Survival (PFS). PFS is the length of time a patient lives with the disease without it getting worse. In the FLAURA study, the median Progression-Free Survival for patients taking Tagrisso was 18.9 months. It is important to understand that “median” represents the midpoint; half of the patients in the trial continued on the treatment without their cancer progressing for longer than 18.9 months, while half experienced progression before this point.
Further research has explored ways to extend this duration. The FLAURA2 trial investigated combining Tagrisso with chemotherapy. The results showed this combination extended the median PFS by an additional 8.8 months compared to Tagrisso alone.
The Profile of a Long-Term Responder
The duration of response to Tagrisso can be influenced by the specific type of EGFR mutation a patient has. Research has consistently shown that patients with a type of mutation known as an exon 19 deletion often experience a more durable response to the treatment. This is in comparison to patients with another common mutation, the L858R point mutation.
Studies analyzing patient outcomes have quantified this difference. One prospective study observed that patients with an exon 19 deletion had a median Progression-Free Survival of 8.0 months compared to 5.2 months for those with the L858R mutation, even after developing resistance to previous therapies. Another analysis focusing on first-line Tagrisso use found that a common exon 19 deletion variant was associated with a median PFS of 21.3 months.
Beyond the mutation type, a patient’s overall health and the extent of the cancer, or disease burden, when starting treatment can also play a role. A lower disease burden at the outset may contribute to a more prolonged period of benefit from the therapy.
Navigating Acquired Resistance
Eventually, for many patients, Tagrisso may stop working effectively. This occurs because cancer cells can be adaptable and evolve new ways to grow despite the presence of the drug, a process known as acquired resistance. A known challenge in targeted cancer therapy is that the cancer essentially finds a new pathway to bypass the blockade created by the medication.
When resistance is suspected, usually due to signs of cancer progression on imaging scans, doctors often recommend another biopsy of the tumor. This new tissue sample is analyzed to understand the specific mechanism of resistance that has developed. The most common mechanisms include the cancer developing a new mutation in the EGFR gene, such as C797S, or the activation of an entirely different growth pathway, like MET amplification.
Understanding the reason for the resistance is a guide for determining the next steps. For some, this may mean switching to a different type of treatment, such as traditional chemotherapy or radiation. For others, it could open the door to participating in a clinical trial investigating new drugs designed to overcome specific resistance mechanisms. This approach of re-testing the cancer and adjusting the treatment strategy is a continuous process in modern cancer care.