ON 123300 (Narazaciclib) and Dexamethasone in Patients With Relapsed and/or Refractory Multiple Myeloma

"dosed starting at 200 mg of ON 123300 (NARAZACICLIB) daily for four weeks. Dose levels will be 160 mg, 200 mg, 240 mg, 280 mg, 320 mg. Treatment cycles will be four weeks long.~ON 123300 (NARAZACICLIB) is available as an oral formulation ON 123300 (NARAZACICLIB) monolactate capsules (containing 40 mg free base) and is provided in 120 cc high-density polyethylene (HDPE) bottles with child-resistant closures containing 30 hard gelatin capsules. ON 123300 (NARAZACICLIB) is also available in tablet form. The tablets are 40 mm (oblong) and 120 mg (round). Either form, capsules or tablets, may be used in this study."

Weekly oral dexamethasone 20mg