공시 • Sep 16
MacroGenics, Inc. Announces Updated Efficacy & Safety Data from TAMARACK Phase 2 Study of Vobra Duo in mCRPC Patients at ESMO Congress 2024
MacroGenics, Inc. presented updated efficacy and safety results from the TAMARACK Phase 2 study of vobramitamab duocarmazine (vobra duo), an antibody-drug conjugate (ADC) that targets B7-H3, for patients with metastatic castration-resistant prostate cancer (mCRPC). The data were featured in a poster presentation at the European Society for Medical Oncology (ESMO) Congress, taking place in Barcelona, Spain from September 13-17, 2024. TAMARACK Study Demographics: The abstract submitted to ESMO was based on a data cut-off as of April 12, 2024; updated data based on a cut-off date of July 9, 2024, are included below and are reported in the Company’s poster presentation at ESMO. The TAMARACK trial enrolled a total of 181 participants, with 176 participants receiving at least one dose of vobra duo at either 2.0 mg/kg q4W (n=90) or 2.7 mg/kg q4W (n=86). As of the data cut-off date, 23 and 16 participants remained on treatment in the 2.0 mg/kg and 2.7 mg/kg cohorts, respectively. While mCRPC study participants are no longer being dosed in the study, participants continue to be monitored for adverse events, disease progression, and survival. Baseline Characteristics: Enrolled study participants had a median age of 70 years (range, 35-89). 88 Study participants (48.6%) had an ECOG performance status of 1 or 2. 30 Study participants (16.6%) had visceral disease at baseline, with liver or lung disease in 25 participants (13.8%). 81 Study participants (44.8%) had measurable disease at baseline, and 97 (53.6%) had received prior taxane. Both treatment arms were well-balanced across most baseline characteristics, including prior use of taxanes, androgen receptor axis-targeted (ARAT) treatment, poly-ADP ribose polymerase (PARP) treatment, and baseline PSA. TAMARACK Efficacy Results as of July 9, 2024 Cut-off Date: Overall, the Company believes that the results to date from the TAMARACK study indicate antitumor activity associated with vobra duo in mCRPC as demonstrated by the protocol-specified primary endpoint of landmark 6-month radiographic progression-free survival (rPFS) rate, as well as other measures of tumor response. In the intent-to-treat (ITT) population, 6-month rPFS rate was 69% for the 2.0 mg/kg arm (95% CI, 57-79) and 70% for the 2.7 mg/kg arm (95% CI, 58-79). Landmark 6-month rPFS rates were consistent across taxane-naïve study participants (ranging from 66-82%) and taxane pre-treated study participants (ranging from 60-73%), regardless of treatment arm. Although immature, with only 65 PFS events (35.9%) as of the data cut-off, median rPFS was approximately 8.5 months for the 2.0 mg/kg cohort (95% CI, 7.2-11.2) and 7.5 months for the 2.7 mg/kg cohort (95% CI, 7.2-10.6). Because these results were immature as of the cutoff date, they are likely to change as additional events accrue. Tumor response rates - Out of 45 RECIST-response evaluable patients in the 2.0 mg/kg arm, the confirmed objective response rate (ORR) was 20.0% (n=9) and the unconfirmed ORR was 26.7% (n=12). Out of 32 RECIST-response evaluable patients in the 2.7 mg/kg arm, the confirmed ORR was 40.6% (n=13) and the unconfirmed ORR was 46.9% (n=15). Confirmed ORR was comparable between taxane-naïve study participants (26.7%, n=12/45) and taxane pre-treated study participants (17.5%, n=11/63), regardless of treatment arm. Tumor responses did not appear to correlate with baseline B7-H3 expression based on archival tissue samples of mixed age. TAMARACK Safety Results as of July 9, 2024 Cut-off Date: Overall summary of adverse events (AEs) - In the 2.0 mg/kg cohort, 65.6% of study participants (n=59) experienced a Grade =3 treatment-emergent AE (TEAE); this cohort had a discontinuation rate of 25.6% (n=23) and a dose reduction rate of 50.0% (n=45) due to TEAEs. In the 2.7 mg/kg cohort, 62.8% of study participants (n=54) experienced a Grade =3 TEAE; this cohort had a discontinuation rate of 38.4% (n=33) and a dose reduction rate of 54.7% (n=47) due to TEAEs. The most common (occurring in =20% of study participants) all-grade TEAEs were: asthenia, edema peripheral, decreased appetite, nausea, pleural effusion, diarrhea, fatigue, constipation, anemia, palmar-plantar erythrodysesthesia (PPE, or hand-foot syndrome), neutropenia, and stomatitis. The majority of TEAEs with a =10% incidence rate in either treatment arm was limited to Grade 1/2 events. Rates of pleural effusion, pericardial effusion, and PPE for both the 2.0 mg/kg cohort (28.8%, 13.3%, 18.9%, respectively) and the 2.7 mg/kg cohort (44.2%, 17.5%, 28%, respectively) decreased compared to the Phase 1 mCRPC dose expansion cohort (48.8%, 17.1%, 46.3%, respectively), despite an increased median number of doses of vobra duo administered on TAMARACK. Eight fatal treatment-related AEs as assessed by the treating physician: five in the 2.0 mg/kg cohort and three in the 2.7mg/kg cohort. These include three events of pneumonitis, and one event each of cardiac failure, stress cardiomyopathy, ventricular fibrillation, pleural effusion, and gastrointestinal hemorrhage. Rates of treatment-related AEs (including all grades and Grade =3) and treatment-related severe AEs were similar between taxane-naïve and taxane pre-treated study participants. Tolerability findings -In the 2.0 mg/kg cohort, 25.6% of study participants (n=23) remained on study drug as of July 9, 2024. Study participants received a median number of 6 doses (range, 1-11), with a median dose intensity (calculated as a percentage of the total planned dose that was administered) of 92.6% (range, 64.2-106.1%). In the 2.7 mg/kg cohort, 18.6% of study participants (n=16) remained on study drug as of the data cut-off date. Study participants received a median number of 6 doses (range, 1-12), with a median dose intensity of 81.7% (range, 40.5-104.3%). Taxane-naïve study participants experienced higher rates of dose reductions due to TEAEs (62.7%) and dose interruptions due to TEAEs (70.7%) compared to taxane pre-treated study participants (44.6% and 43.6%, respectively).