Biotech Values

[DewDiligence]

IMGN presents full Elahere dataset from MIRASOL trial:

https://www.businesswire.com/news/home/20230604005024/en

MIRASOL is a randomized Phase 3 trial of ELAHERE versus investigator's choice (IC) of single-agent chemotherapy (weekly paclitaxel, pegylated liposomal doxorubicin, or topotecan). Eligibility criteria include patients with PROC [platinum-resistant ovarian cancer] whose tumors express high levels of FRa, using the Ventana FOLR1 Assay, and who have been treated with up to three prior regimens.

The primary endpoint of this trial is progression-free survival (PFS) by investigator assessment. Key secondary endpoints include objective response rate (ORR) and overall survival (OS).

MIRASOL enrolled 453 patients. Patients were stratified by number of prior lines of therapy (14% had one prior line of therapy, 40% had two prior lines of therapy, and 46% had three prior lines of therapy) and by IC chemotherapy, with paclitaxel as the most commonly chosen (41%), followed by PLD (36%) and topotecan (23%). 62% of patients received prior bevacizumab; 55% received a prior PARP inhibitor.

• ELAHERE demonstrated a statistically significant and clinically meaningful improvement in PFS by investigator assessment compared to IC chemotherapy, with a hazard ratio (HR) of 0.65 (95% confidence interval [CI]: 0.52, 0.81; p<0.0001)… The median PFS in the ELAHERE arm was 5.62 months (95% CI: 4.34, 5.95) compared to 3.98 months (95% CI: 2.86, 4.47) in the IC chemotherapy arm.

• ELAHERE demonstrated a statistically significant and clinically meaningful improvement in OS compared to IC chemotherapy. With 204 OS events reported as of March 6, 2023, the median OS was 16.46 months (95% CI: 14.46, 24.57) in the ELAHERE arm, compared to 12.75 months (95% CI: 10.91, 14.36) in the IC chemotherapy arm, with a HR of 0.67 (95% CI: 0.50, 0.89; p=0.0046).

• ORR by investigator assessment in the ELAHERE arm was 42.3% (95% CI: 35.8%, 49.0%), including 12 complete responses (CRs), compared to 15.9% (95% CI: 11.4%, 21.4%), with no CRs, in the IC chemotherapy arm.

• In the bevacizumab-naïve subset (n=172), the PFS HR was 0.66, (95% CI: 0.46, 0.94; p=0.0210); in the bevacizumab-pretreated subset (n=281), the PFS HR was 0.64 (95% CI: 0.49, 0.84; p=0.0011).

• In the bevacizumab-naïve subset, the OS HR was 0.51 (95% CI: 0.31, 0.86; p=0.0099); in the bevacizumab-pretreated subset, the OS HR was 0.74 (95% CI: 0.54, 1.04; p=0.0789).

• PFS and ORR results by blinded independent central review (BICR) were concordant with investigator assessment. …ORR by BICR in the ELAHERE arm was 36.1% (95% CI: 29.9, 42.7), including 16 complete responses (CRs), compared to 14.6% (95% CI: 10.3, 19.9), with 4 CRs, in the IC chemotherapy arm.

• ELAHERE was well-tolerated, consistent with the known safety profile seen in the broader development program. No new safety signals were identified in MIRASOL.

Some of these data—PFS HR, OS HR, and ORR by investigator assessment for the full trial—were reported on 5/3/23 (#msg-171829776). Newly reported data today include: PFS/OS for the Avastin-naïve and Avastin-pretreated subgroups; and PFS and ORR for the full trial as measured by blinded central review.