Merck Combination Drug Approved by FDA Expected to Prolong Survival in Lung Cancer – Is the Biologic Keytruda the Missing Link?
The Food and Drug Administration (FDA) approved a new combination drug therapy after cohort studies found the addition of immunotherapy drug Keytruda (pembrolizumab) to standard chemotherapy treatments of pemetrexed and carboplatin for patients with metastatic or advanced nonsquamous non-small cell lung cancer (NSCLC) sped up response time to treatment and halted cancer progression over use of chemotherapy alone.
The addition of the immunotherapy drug which has doctors and patients excited appears to be the missing link in advanced and refractory treatment of lung cancer. Keytruda is a humanized monoclonal antibody which increases the ability of the body’s immune system to help detect and fight tumor cells by activating T lymphocytes.
Progression free survival (PFS) improved a full 10% from 78% in the control group to 88% with the addition of Keytruda at the 10.6 month follow up. PFS at 6 months was 63% in the chemo group and 77% for patients on combination Keytruda/chemotherapy, at which time 78% of patients in both groups remained alive.
Adverse events in the Keytruda and chemotherapy groups included constipation, diarrhea, fatigue, fever, rash, nausea and vomiting but there was a lower discontinuation rate of 10% in the Keytruda group as compared to 13% in the control group.
Grade 3 and higher adverse events for the Keytruda patients included decreased hemoglobin, lymphocytes, neutrophils and platelets.
The expedited approval is contingent upon results of a phase 3 trial being conducted now that is estimated to end in March 2019. The study will primarily analyze PFS but will also look at overall survival (OS) and overall response rate (ORR). Patients included in the study with a diagnosis of untreated squamous NSCLC will be given platinum-based chemotherapy plus pemetrexed with or without Keytruda. For purposes of this study, researchers will decide between cisplatin or carboplatin as their platinum-based chemotherapy of choice. Patients will also receive dietary supplement Folic acid 350-1000 μg, Vitamin B12 1000 μg and Dexamethsone 4 mg. The study goal is to accrue 570 patients to participate.
If the suspected results are consistent with the cohort studies final approval is expected.