Rain Therapeutics Inc. announced that the first patient has been dosed in the multicenter, single arm, open-label, Phase 2 basket trial evaluating milademetan, an oral mouse double minute 2 (MDM2) inhibitor, for the treatment of MDM2-amplified advanced solid tumors. The MANTRA-2 trial is designed to evaluate the safety and efficacy of milademetan in patients with advanced or metastatic solid tumors refractory or intolerant to standard-of-care therapy and that exhibit wild-type p53 and a prespecified minimum MDM2 gene copy number. Approximately 65 patients are anticipated to be enrolled to receive milademetan. The primary endpoint of the trial is objective response rate as measured by RECIST criteria. Secondary endpoints include duration of response, disease control rate progression-free survival by investigator assessment, overall survival and, and growth modulation index. An interim analysis from MANTRA-2 is anticipated in the second half of 2022.