Rain Enhancement Technologies Holdco Inc Q1 FY2023 earnings call

• Avanish Vellanki noted that Rain achieved the required events to trigger analysis of the primary endpoint in the global Phase 3 MANTRA study for milademetan, expecting top-line data this quarter. - Bob Doebele discussed p53 reactivation, MEK inhibitor combination synergy in pre-clinical models, and broad activity of milademetan across different oncogene-driven models. - Richard Bryce provided updates on clinical trials: MANTRA-2 basket study enrolling patients with MDM2 amplification, MANTRA-4 Phase 1/2 trial with Roche's atezolizumab on track to start mid-2023, and expectations for NDA submission in DDLPS if MANTRA data is favorable.

For the three months ended March 31, 2023, Rain reported a net loss of $20.5 million compared to a net loss of $17.4 million in the same period of 2022. Net loss per share was $0.56 vs $0.66 in 2022. Research and development expenses were $16.7 million vs $13.6 million in 2022, due to clinical trial costs for milademetan, higher R&D personnel payroll, and other R&D costs. General and administrative expenses were $5.1 million vs $3.9 million in 2022, driven by higher professional services, legal costs, and payroll. Cash, cash equivalents, and short-term investments were $109.8 million as of March 31, 2023.

• Expect top-line data from the global Phase 3 MANTRA study this quarter. - Cash position at end of first quarter provides runway to complete ongoing and planned clinical trials of milademetan, including Phase 3 MANTRA, Phase 2 MANTRA-2, and Phase 1/2 MANTRA-4 trials.

Q: Yigal Nochomovitz asked about early signs of tumor reductions in solid tumors in the MDM2 amp basket trial.

A: Robert Doebele said they saw tumor reductions in lung, pancreatic, breast, and biliary cancer patients, all p53 wild-type with MDM2 amplification.

Q: Michael Schmidt asked about MANTRA trial follow-up for OS and pricing analogs.

A: Richard Bryce said OS data would be immature; Avanish Vellanki mentioned ripretinib and other sarcoma programs as pricing analogs.

Q: Joe Catanzaro asked about top-line disclosure in MANTRA and MEK inhibitor combination mechanism.

A: Avanish Vellanki said level of disclosure not known yet; Bob Doebele discussed MEK inhibitor combination mechanisms and potential extrapolation to other targeted therapies.

Q: Soumit Roy asked about scientific publication of MANTRA trial.

A: Avanish Vellanki said a publication would make sense but timing not specified.

Q: Sam Slutsky asked about MANTRA trial timelines post-top-line and MANTRA-2 enrollment post-copy number change.

A: Richard Bryce discussed MANTRA study stats assumptions; Robert Doebele said enrollment in MANTRA-2 picked up due to multiple factors including copy number change.

Q: Jeff Jones asked about MANTRA-4 timelines.

A: Richard Bryce said MANTRA-4 trial on track to start mid-2023, with safety portion first.

Q: Faisal Khurshid asked about MANTRA control arm assumptions and copy number confidence.

A: Robert Doebele discussed MANTRA control arm based on trabectedin data and confidence in copy number cutoff for MANTRA-2.

Q: Mitchell Kapoor asked about solid tumor plans post-MANTRA-2.

A: Avanish Vellanki said they would review data to determine next steps for MANTRA-2.

Q: Avantika Joshi asked about MANTRA-2 ex-U.S. site expansion and implications of MANTRA not reading out positively.

A: Richard Bryce said expanding MANTRA-2 sites on track; Avanish Vellanki said scenario planning done but not disclosed.

Q: Tony Butler asked about tumor heterogeneity in DDLPS.

A: Robert Doebele discussed p53 reactivation inducing growth arrest or apoptosis, and heterogeneity in dedifferentiated liposarcoma patients.