In a panel of 750 cell lines, acute degradationof ERK5 with INY-06-061did not result in decreased proliferation (all IC50 valuesexceeded 1 μM), and in IL-6-stimulated multiple myeloma MM.1Scells, INY-06-061 also had no antiproliferative effect. The gene discussed is MAPK7; the disease is plasma cell myeloma.