FDA Grants Priority Review to Afatinib for NSCLC With Rare EGFR Mutations

Excerpt:

“The FDA has granted a priority review to a supplemental new drug application (sNDA) for afatinib (Gilotrif) for the frontline treatment of patients with metastatic non–small cell lung cancer (NSCLC) whose tumors harbor EGFR exon 21 (L861Q), G719X, or S768I substitution mutations.

“Uncommon mutations such as these represent less than 10% of the EGFR mutations found in NSCLC patients, but are associated with poor prognosis and survival, Boehringer Ingelheim, the manufacturer of afatinib, noted in a press release.”

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EGFR-mutant NSCLC: Choice of First-Line Treatment May Get More Complicated


Medical guidelines for treatment of newly diagnosed non-small cell lung cancer (NSCLC) mandate upfront testing of tumor tissue for mutations in the EGFR gene (as well as ALK and ROS gene translocation). EGFR mutations are found in 10 to 15% of white patients, but in patients of East Asian origin such mutations are in encountered in approximately 48%. However, with new data and drugs entering the playing field, newly diagnosed patients’ treatment decisions could become more complex.

There is a good reason to test for EGFR mutations: the accumulated data show that, compared to first-line chemotherapy, treatment with drugs that inhibit the activity of EGFR in patients with activating EGFR mutations improves patients’ median progression-free survival (PFS) time from 4.6 to 6.9 months to 9.6 to 13.1 months, and has a higher objective response rate (ORR). Moreover, EGFR inhibitors are associated with a significantly lower incidence of adverse effects and better control of disease symptoms.

About 90% of EGFR mutations in EGFR are deletions in a portion of the gene known as exon 19 or a mutation in exon 21 (these mutations are known as del19 and L858R, respectively). The remaining mutations include alterations in exons 18 and 20, and these are associated with poor response to EGFR inhibitors.

The presence of the EGFR mutations del19 or L858R usually prompts doctors to prescribe one of the three EGFR inhibitors approved by the U.S. Food and Drug Administration (FDA) as a first-line treatment: erlotinib (Tarceva), gefitinib (Iressa), or afatinib (Gilotrif). Erlotinib and gefitinib are first-generation EGFR inhibitors, and afatinib is a second-generation drug. The first-generation inhibitors bind EGFR reversibly (they can attach and detach), whereas second generation inhibitors like afatinib bind to EGFR in an irreversible manner. All three inhibit not only the mutated EGFR protein, but also the normal EGFR that performs essential functions in some normal tissues. Afatinib also inhibits other members of the EGFR family of proteins (HER2 and HER4).

It is worth noting that none of these three drugs improve overall survival, with one exception, which I discuss later. The major side effects of EGFR inhibitors are skin rash and diarrhea, and the latter can be more severe with afatinib. In general, side effects are usually manageable and often transient, and by now, doctors have acquired much experience on how to alleviate them. Also, dose reductions to reduce side effects are possible with erlotinib and afatinib (but not with gefitinib). Gefitinib in general has lower risk of toxicities.

The choice between the three available inhibitors may depend on several factors: the oncologist’s preferences, the patient’s general condition, and importantly, the precise EGFR mutations identified in the patient’s tumor(s).

The del19 mutation is known to have the highest response rate to EGFR inhibitors amongst all EGFR mutations. A direct comparison in a large clinical trial showed an ORR of 72.5% with afatinib and 56% with gefitinib. There was no difference in PFS, but there was a trend in prolongation of overall survival with afatinib (27 versus 24 months).

Therefore, patients with del19 who are in a good overall condition should be given afatinib. The prevailing opinion is that gefitinib should be given to frail or older patients, or patients with other health concerns.

EGFR mutations other than L858R or del19, such as exon 20 insertions or exon 18 mutations, respond poorly to erlotinib and gefitinib. Patients whose tumors have these mutations do not have good treatment options, but are usually treated with afatinib, which has been shown to have better activity then first-generation inhibitors. There are now drugs in clinical trials specifically for patients with exon 20 insertions: a combination of poziotinib and AP32788, and osimertinib.

Obviously, the choice between the three FDA-approved first-line drugs requires careful consideration. However, it is apparently about to become a lot more difficult, with new contenders for first-line treatment in EGFR mutant NSCLC coming onto the scene. A combination of erlotinib with bevacizumab, a drug that limits blood supply to tumors, has already shown a superior PFS of 16 months versus 10 months with erlotinib alone. Another, and likely a stronger candidate, is osimertinib (Tagrisso), a third-generation inhibitor that does not bind to normal EGFR. Osimertinib is already FDA-approved for treatment of NSCLC with an EGFR mutation known as T790M.

T790M is very rarely found in untreated lung cancer, but arises during treatment with FDA-approved EGFR inhibitors in about 40 to 60% of patients, making them resistant to further treatment with first/second generation EGFR inhibitors. Osimertinib was developed to treat patients with T790M and has a reported ORR of 61%, which is very impressive. This is much higher than what is seen with chemotherapy in patients with resistance to first-line EGFR inhibitors: in a direct comparison in the AURA3 trial, a response rate of 71% was seen with osimertinib versus only 31% with chemotherapy. Moreover, osimertinib has activity (albeit much lower) even in the absence of a T790M mutation after resistance to erlotinib or gefitinb develops.

This latter feature led to testing of osimertinib as a first-line treatment in EGFR-mutant NSCLC. The trial included 60 patients who received two different doses of the drug, and the average ORR was 77%, with a median PFS of 20.5 months. These PFS data are much better than what is seen with any of the three FDA-approved first-line EGFR inhibitors (10 to 12 months).

There is a much larger trial ongoing, named FLAURA, which directly compares osimertinib with erlotinib or gefitinib in the frontline setting for patients with advanced EGFRmutant NSCLC. There is little doubt that the results, when published, would favor osimertinib, and this has been already announced in a press release issued by the trial sponsor.

It is possible that the FDA will approve osimertinib as the first-line treatment option for EGFR-positive NSCLC, which will make the choice of first-line drug difficult. What is better: sequence the available drugs, i.e., start with erlotinib followed by osimertinib when resistance develops (if T790M is identified), or give osimertinib outright?

Doing a simple calculation, erlotinib first may provide PFS of 9-13 months, followed by osimertinib (if T790M is present), adding another 10 months. Osimertinib given as first line can provide 20 months PFS. However, resistance to approved first-line EGFR inhibitors involves T790M in 40 to 60 % of patients, so perhaps it is more useful to use osimertinib right away? Not an easy question to answer. It would be wonderful if data could be somehow collected for the many patients who were treated with erlotinib, developed T790M mutation, and switched to osimertinib, rather than to conduct randomized trials. But this is unlikely to happen.


Lung Cancer Highlights from ASCO 2016


This year, the Annual Meeting of the American Society of Clinical Oncology (ASCO) did not produce any truly groundbreaking revelations about new treatments for lung cancer. However, researchers did report quite a few positive findings, and some disappointing ones. I have summarized some of the more prominent presentations below. Continue reading…


US Widens Use of Boehringer's Lung Cancer Drug Gilotrif

Excerpt:

“US health officials have expanded the approved indications for Boehringer Ingelheim’s Gilotrif, clearing its use in patients with squamous cell carcinoma of the lung.

“Gilotrif (afatinib), an oral, once-daily EGFR-directed therapy, is currently cleared in the US for the first-line treatment of specific types of EGFR mutation-positive non-small cell lung cancer.

“Approval for squamous cell carcinoma of the lung, a disease linked with a particularly bleak poor prognosis of one-year survival post diagnosis, was based on data from the head-to-head LUX-Lung 8 trial in patients whose tumours progressed after first-line chemotherapy.”

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CHMP Recommends Afatinib for Second-Line NSCLC

“Afatinib (Giotrif, EU; Gilotrif, US) has received a positive recommendation from the Committee for Medicinal Products for Human Use (CHMP) as a treatment for patients with advanced squamous cell non–small cell lung cancer (NSCLC) following progression on platinum-based chemotherapy, according to Boehringer Ingelheim, the manufacturer of the irreversible EGFR inhibitor.

“The CHMP opinion, which recommends that the treatment should gain approval from the European Medicines Agency in this setting, is based on data from the phase III LUX-Lung 8 trial. In the study, second-line afatinib reduced the risk of both disease progression and death by 19%, compared with erlotinib (Tarceva) in patients with advanced squamous cell carcinoma of the lung.”


Afatinib Shows Clinical Benefit for Lung Cancer Patients with Brain Metastases

“Non-small cell lung cancer (NSCLC) patients with common epidermal growth factor (EGFR) mutations and brain metastases showed improved progression-free survival (PFS) and response from the EGFR tyrosine kinase inhibitor (TKI) afatinib compared to standard platinum doublet chemotherapy.

“More than 25% of with advanced NSCLC experience progression to the brain from their primary lung and this number increases to 44-63% for those NSCLC tumors driven by EGFR mutations. Prognosis is poor and typically ranges for 1-5 months for those with . EGFR TKIs are highly effective therapies for advanced NSCLC driven by EGFR mutations, especially the common mutations, exon 19 deletions and L858R point mutations. Even though there are a number of EGFR TKIs approved for first-line therapy of EGFR mutation positive NSCLC, there is a scarcity of prospective data for EGFR TKIs in patients with brain metastases.”


Afatinib a Better Choice for EGFR-Mutated Lung Cancer in First-Line Treatment

“Patients with EGFR-activating mutations in advanced lung cancer seem to benefit more from afatinib than gefitinib as first-line treatment, researchers report at the first ESMO Asia 2015 Congress in Singapore.

“In the global, randomised, open-label Phase IIb LUX-Lung 7 (LL7) trial, the irreversible ErbB family blocker afatinib significantly improved efficacy versus gefitinib across a range of clinically relevant endpoints, such as progression-free survival, time-to- failure and objective response rate. ‘Based on these results I would consider afatinib as the EGFR (TKI) of choice for the first-line treatment for patients with EGFR mutation-positive non-small-cell (NSCLC),’ lead author, Professor Keunchil Park, head of the Division of Hematology/Oncology at Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea, said.”


No Benefit to Afatinib in HER2-Positive Breast Cancer With Brain Metastases

“The use of afatinib or afatinib plus vinorelbine during or after treatment with trastuzumab, lapatinib, or both failed to show a patient benefit in women with HER2-positive breast cancer with progressive brain metastases compared with investigator’s choice of treatment, according to the results of a phase II study published in Lancet Oncology.

“Afatinib, an oral inhibitor of the ErbB family of proteins, did benefit about one-third of patients assigned to the treatment, but had no better activity than investigator’s choice of therapy, which consisted mostly of trastuzumab or lapatinib plus chemotherapy.

“ ‘No objective responses were achieved in patients treated with afatinib alone, but around one-third of patients, including those treated with afatinib alone, did not have disease progression during the first 12 weeks,’ wrote researcher Javier Cortés, MD, of Vall d’Hebron Institute of Oncology in Barcelona, and colleagues. ‘No further development of afatinib for HER2-positive breast cancer is currently planned.’ “


Mutation Status Guides Advanced NSCLC Therapy

“The presence or absence of mutations in advanced non-small cell lung cancer (NSCLC) should guide selection of first-line systemic therapy, according to an updated clinical guideline from the American Society of Clinical Oncology.

“Patients with squamous-cell tumors that have no gene alterations should begin treatment with combination platinum-based cytotoxic chemotherapy, so long as they have good performance status (0 or 1). Optionally, bevacizumab (Avastin) may be added when the platinum agent is carboplatin. For patients with performance status 2, either chemotherapy or palliative care alone is an acceptable option.

“In the presence of sensitizing EGFR mutations, appropriate first-line therapy is afatinib (Gilotrif), erlotinib (Tarceva), or gefitinib (Iressa). Treatment should begin with crizotinib (Xalkori) when patients have tumors with ALK or ROS1 rearrangements, as published online in the Journal of Clinical Oncology.”