Amgen's rhymes with:
mutagens, arbenz, boatmen's, cortens, cortens', dornhens, emens, freemen's, garsten's, houten's, kamens, midshipmen's, mutagens, servicemen's, uelmen's
Amgen's sounds like:
ahmanson's, ahmansons, amassing, amazing, amazon's, amazonians, amazons, amusing, anagnos, anguishing, annexing, announcing, ansang