AACR 2019 – Keytruda’s small-cell benefit is driven by PD-L1

As Merck & Co prepares to chase Roche in first-line small-cell lung cancer it can today point to results in a third-line setting that show Keytruda to be at least the equal of Bristol-Myers Squibb’s Opdivo. This might not be saying much, however, as Opdivo’s third-line SCLC label is under threat after the drug flunked two potentially confirmatory studies, Checkmate-331 and 451. The Merck analysis, presented at the AACR meeting, concerns pooled data from the Keynote-028 and 158 trials of Keytruda, and shows the importance of PD-L1 status in this cancer: 14 of 16 reported responses were seen in PD-L1-positives, and the overall remission rate in the 47 PD-L1-positive subjects was 30%. Pooled median overall survival for Keytruda of 7.7 months compares favourably with the standard of care’s 3.8 months. Meanwhile, Pharmamar’s Zepsyre is in the second-line Atlantis trial, reading out at the end of 2019, and met a 30% response rate threshold in a monotherapy basket study. Roche’s Tecentriq was recently approved first line on the basis of Impower-133; Astrazeneca’s Caspian study of Imfinzi and Merck’s Keynote-604 trial – both front line – were due to yield data early this year, but have been delayed to September and December respectively.

Cross-trial comparison in ≥3rd line SCLC
  Patients ORR 12mth OS 12mth PFS Median OS Median PFS
Checkmate-032* 109 12% 39% 8% Not yet reported
Keynote-028** & 158 pooled 83 19% 34% 17% 7.7mth 2.0mth
Source: AACR & Asco; *basis for accelerated approval; **PD-L1+ves only.

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