Xalkori (crizotinib), a lung cancer drug that was approved in 2011 under the Food and Drug Administration’s accelerated approval, has passed the last hurdle to regular approval. On Nov. 20, the FDA gave the ruling after a phase 3 clinical study confirmed that the drug works in patients who have metastatic cancer with a particular genetic mutation called ALK and who had progressed on platinum-based chemotherapy. Specifically, Xalkori works in lung cancers that are driven by a mutation in the anaplastic lymphoma kinase (ALK) gene, which occurs in about 5 percent of non-small cell lung cancers.
Accelerated approval is a conditional approval the FDA grants for drugs that show a significant improvement before a trial is completed. It can be based on survival, delayed disease progression or another endpoint that was pre-determined before the trial began. Efficacy of the drug must be verified in a later study, either a phase 3 or 4 trial before it can be given a regular approval.
Previous results, which led to the accelerated approval, were based on two single-arm studies, meaning all patients in the study received the investigational drug rather than being randomly assigned to receive the investigational drug or a standard of care. These studies showed Xalkori improved objective response rates, meaning the tumors shrunk with Xalkori in 50 percent and 61 percent of the time in the two studies, respectively.
[Xalkori approved for non-small cell lung cancer – Sept 1, 2011]
This new approval is based on results that showed the drug delayed disease progression for 7.7 months compared to chemotherapy, which only kept the cancer from growing for 3 months. Side effects included vomiting, diarrhea, constipation, fatigue and vision impairments.
Many accelerated approvals later receive regular approval. A paper examining accelerated approvals and post-marketing studies found that from Dec. 11, 1992 to July 1, 2010, the FDA granted 35 oncology products accelerated approval, which accounted for 47 new indications. Clinical benefit was later confirmed in subsequent studies for 26 of the 47 new indications. The average time between accelerated approval and regular approval was more than four years, but ranged anywhere from less than a year to more than 12 years. During that time, three indications were revoked or had a restricted distribution due to follow-up studies.
To better understand this newest approval for Xalkori, we asked the FDA a few questions:
1. What is the significance of the regular approval for Xalkori?