Following strong second quarter sales growth for Bristol-Myers Squibb Co.'s PD-1 inhibitor, Opdivo (nivolumab), the FDA has granted it an accelerated approval for the treatment of adults and children with microsatellite instability-high (MSI-H) and mismatch repair deficient (dMMR) metastatic colorectal cancer (CRC), that has progressed following previous treatment with a fluoropyrimidine, oxaliplatin and irinotecan.
However, the approved indication is narrower than its prime rival, Merck & Co. Inc.'s PD-1 inhibitor Keytruda (pembrolizumab) which was additionally approved in May by the FDA for patients with all tumor types with these dMMR or MSI-H biomarkers. (Also see "Keytruda Approval Opens New Routes For Immuno-Oncology" - Scrip, 24 May, 2017.) Datamonitor Healthcare analyst Hardik Patel says this means Keytruda still holds the target population advantage. Patients with dMMR or MSI-H tumors are less likely to respond to conventional chemotherapy, and CRC is the most commercially significant market segment.
Around 15% of patients suffering from metastatic colorectal cancer have dMMR or MSI-H tumors which, according to Patel, is a large subgroup considering the high prevalence of CRC. However, "the presence of a direct competitor for this patient population in Keytruda, drastically reduces Opdivo’s potential in this setting," he said.
Opdivo is already launched for melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, Hodgkin's lymphoma, head and neck, and bladder cancers. Sales for the drug were at $1.19bn this second quarter, up by 42% from the same quarter last year. The product seems to be maintaining its market share in face of competition from the newer PD-L1 inhibitors, and it has enjoyed continued adoption across second-line NSCLC and renal cancer (see sidebar).
The latest Opdivo approval is mainly based on data from the CheckMate-142 trial, which showed that among patients (53/74) who received prior treatment with a fluoropyrimidine, oxaliplatin, and irinotecan, 28% responded to treatment with Opdivo. 1.9% had a complete response, and 26% had a partial response. Among these responders, the median duration of response was not reached. Data from CheckMate -142 were published in The Lancet Oncology in July.
But Patel noted Keytruda also produced a higher overall response rate of 39.6%, which lasted six months or more in 78% of patients, in the collection of data from 149 patients with these biomarkers in five trials. Opdivo's ORR of 28% lasted for the same amount of time in 67% of patients. However, Patel underlined that these results should not be directly compared "as Keytruda’s trial included patients with 14 tumor different types in addition to CRC, which could have positively or negatively impacted the overall outcomes due varying response rates."
BMS's development program for Opdivo continues, particularly in combination use, although the recent PFS failure in AstraZeneca's MYSTIC study has cast a pall over this field (Also see "MYSTIC Misses: Devastation For AstraZeneca As Imfinzi Fails PFS Endpoint In NSCLC" - Scrip, 27 Jul, 2017.). Opdivo is being studied in combination with BMS' CTLA-4 inhibitor Yervoy (ipilimumab) for lung cancer.