Dose adjustments
toxicity, toxicities, death
The pre-operative dose of abemaciclib will not be adjusted for lower dosing for drug-related toxicities on this study due to the short duration of therapy (detailed PK findings of abemaciclib based on standard dosing). Any grade 3 or higher toxicity that is deemed attributable to abemaciclib within the first 4.5 days will require drug discontinuation and removal from study. Those participants will be replaced. Any other toxicities seen prior to surgery that make surgery not feasible or unsafe will also require discontinuation of therapy, removal from study and replacement. If grade 3 or higher toxicity is noted during maintenance therapy (abemaciclib combined with temozolomide), then both therapies will be held until symptoms resolve to grade 1–2. After resolution, will restart temozolomide dosing at 150mg/mIf the toxicity is likely or potentially related to abemaciclib, the appropriate dose reductions for abemaciclib must occur. If it is likely or potentially related to temozolomide, then appropriate dose reductions for temozolomide should be made. If it is not possible to attribute the toxicity to either drug, consider reducing both. If a participant must stop one of the study drugs, then they will be taken off treatment and followed until death.Management of drug holds, and supportive care will be at the discretion of the PI. If the participant requires discontinuation of the drug due to prolonged grade 3 or higher toxicity, they will be removed from the study protocol directed therapy and monitored closely until toxicities resolve; and then every 6 months until death.