Hundreds of Imdelltra Side Effects Went Unreported to FDA Before Cancer Drug’s Approval: Report

Imdelltra is used to treat small cell lung cancer, an aggressive cancer usually linked to tobacco use, which has seen little treatment improvement in 30 years.

In May, the U.S. Food and Drug Administration (FDA) approved the use of Imdelltra, an Amgen drug designed for the treatment of small cell lung cancer. However, it now appears that decision may have been made without the agency having a full understanding of the potential side effects of the cancer drug.

According to a report published by Fierce Pharma on August 14, Amgen failed to give the FDA hundreds of reports involving adverse events that occurred during clinical trials. These unreported Imdelltra side effects were discovered after after an FDA clinical site inspection raised concerns in the agency and were added later in the FDA review process.

FDA documents indicate that Amgen may have withheld nearly 400 adverse event reports that occurred during phase 2 clinical trials. The majority of the unreported incidents involved cytokine release syndrome, which involves the body overreacting to an infection with a systemic inflammatory response, and neurotoxicity.

Although the FDA has determined that the unsubmitted reports did not affect the agency’s interpretation of the drug’s safety profile, the lack of disclosure raises serious questions about the approval process.

Amgen officials told Fierce Pharma that the agency has concluded the clinical trial was conducted using internationally accepted good clinical practice protocols.

Small Cell Lung Cancer Risks

Small cell lung cancer (SCLC) is an aggressive form of lung cancer that quickly spreads to other parts of the body. It is often linked to long-term tobacco use and represents about 15% of all lung cancer diagnoses.

If left undetected, SCLC can form tumors in the lungs, and shed cancer cells which can spread to the lymph nodes, bones, brain, liver, and adrenal glands.

Symptoms can include chest pain, chronic cough, coughing up blood, difficulty breathing, facial swelling, fatigue, hoarseness, loss of appetite, unexplained weight loss, wheezing and swollen neck veins.

Without treatment, most diagnosed with SCLC die within a few months of diagnosis. Even when treated, more than 50% of patients see the cancer return. Only about 7% of those with small cell lung cancer survive longer than five years after being diagnosed.

Amgen officials indicated there had been little progress on treatment of SCLC over the last 30 years.