ImmunoGen Announces Top-Line Results from Phase 3 FORWARD I Study of Mirvetuximab Soravtansine in Ovarian Cancer
Trial Did Not Meet Primary Endpoint of Progression-Free Survival
Efficacy Signal Seen in High Folate Receptor Alpha Patients; Additional Analyses to be Conducted
Favorable Tolerability Profile Confirmed
Combination Regimens to be Evaluated as an Independent Path Forward to Support Registration in Ovarian Cancer
Conference Call to be Held at
“Even though FORWARD I did not meet its primary endpoint, I continue to
be impressed with the efficacy and tolerability of mirvetuximab
soravtansine in ovarian cancer patients, especially in the subset with
high FRα expression,” said Dr.
The FORWARD I Phase 3 trial randomized 366 patients 2:1 to receive either mirvetuximab soravtansine or the physician's choice of single-agent chemotherapy (pegylated liposomal doxorubicin, topotecan, or weekly paclitaxel). Eligibility criteria included patients with platinum-resistant ovarian cancer that expressed medium or high levels of FRα who have been treated with up to three prior regimens. The primary endpoint of this study was PFS, which was assessed using the Hochberg procedure in the entire study population and in the subset of patients with high FRα expression. The Hochberg procedure enables the simultaneous testing of two overlapping populations. Under this statistical analysis plan, if the p-value of the primary endpoint in either population is greater than 0.05, the p-value in the other population needs to be less than or equal to 0.025 to achieve statistical significance.
“Based upon the efficacy signals we observed in the high FRα subset with
PFS, confirmed overall response rate and overall survival, we are
conducting additional analyses to further evaluate the potential benefit
of mirvetuximab soravtansine for FRα-positive platinum-resistant ovarian
Key findings from FORWARD I are as follows:
- In the entire study population, the confirmed overall response rate was higher for mirvetuximab soravtansine than for chemotherapy (22% vs 12%, p-value 0.015), without a significant difference in the primary endpoint of PFS (HR 0.98, p-value 0.897) or overall survival (HR 0.81, p-value 0.248).
In the pre-specified high FRα subgroup (218/366, 60%)
- PFS was longer in patients who received mirvetuximab soravtansine compared with chemotherapy (HR 0.69, p-value 0.049). Given that the p-value in the entire study population exceeded 0.05, the statistical analysis plan for the study required the p-value in the high subset to be less than or equal to 0.025 to achieve statistical significance.
- Confirmed overall response rate was higher for mirvetuximab soravtansine than for chemotherapy (24% vs 10%, p-value 0.014).
- Overall survival was longer in patients who received mirvetuximab soravtansine compared with chemotherapy (HR 0.62, p-value 0.033).
- Mirvetuximab soravtansine was well-tolerated, with fewer patients experiencing grade 3 or greater adverse events (46% vs 61%), fewer dose reductions (20% vs 31%), and fewer discontinuations due to drug-related adverse events (5% vs 8%) compared with chemotherapy.
- The safety profile of mirvetuximab soravtansine was confirmed, with the most common adverse events including nausea (54% all grades; 2% grade 3 or greater), diarrhea (44% all grades; 4% grade 3 or greater), and blurred vision (43% all grades; 3% grade 3 or greater).
“This study with mirvetuximab did not result in the outcome that we had
hoped for in platinum-resistant patients. We will further assess the
data from FORWARD I to determine potential next steps with a monotherapy
approach. In parallel, we have generated encouraging data with
mirvetuximab combination regimens and will evaluate our ongoing studies
as an independent path forward to support a registration in ovarian
ImmunoGen intends to present additional results from FORWARD I at an upcoming medical meeting.
CONFERENCE CALL INFORMATION
ImmunoGen will host a conference call on
ABOUT FORWARD I
FORWARD I is a Phase 3 trial in which 366 patients were randomized 2:1 to receive either mirvetuximab soravtansine or the physician's choice of single-agent chemotherapy (pegylated liposomal doxorubicin, topotecan, or weekly paclitaxel). Eligible patients were diagnosed with platinum-resistant ovarian cancer that expresses medium or high levels of FRα and were treated with up to three prior regimens. The primary endpoint of this study was progression free survival (PFS), which was assessed in the entire study population and in the subset of patients with high FRα expression. ImmunoGen estimates that 12,000-14,000 patients per year in the U.S. meet these criteria, with a comparable number in the major markets in
ImmunoGen partnered with the
ABOUT MIRVETUXIMAB SORAVTANSINE
Mirvetuximab soravtansine (IMGN853) is the first folate receptor alpha (FRα)-targeting ADC. It uses a humanized FRα-binding antibody to target the ADC specifically to FRα-expressing cancer cells and a potent anti-tumor agent, DM4, to kill the targeted cancer cells.
ImmunoGen is developing the next generation of antibody-drug conjugates (ADCs) to improve outcomes for cancer patients. By generating targeted therapies with enhanced anti-tumor activity and favorable tolerability profiles, we aim to disrupt the progression of cancer and offer our patients more good days. We call this our commitment to “target a better now.” The Company has built a productive platform generating a broad pipeline of ADCs targeting solid tumors and hematologic malignancies.
Learn more about who we are, what we do, and how we do it at www.immunogen.com.
This press release includes forward-looking statements based on
management's current expectations. These statements include, but are not
limited to, ImmunoGen’s plan to further assess the data from FORWARD I,
ImmunoGen’s expectations with respect to the future development of
mirvetuximab soravtansine as a monotherapy or in combination regimens,
ImmunoGen’s plan to advance its portfolio of next-generation ADCs,
ImmunoGen's ability to expand the addressable patient population for
mirvetuximab soravtansine and the regulatory and commercial potential of
mirvetuximab combinations in earlier lines of therapy. For these
statements, ImmunoGen claims the protection of the safe harbor for
forward-looking statements provided by the Private Securities Litigation
Reform Act of 1995. Various factors could cause ImmunoGen's actual
results to differ materially from those discussed or implied in the
forward-looking statements, and you are cautioned not to place undue
reliance on these forward-looking statements, which are current only as
of the date of this release. It should be noted that there are risks and
uncertainties related to the development of novel anticancer products,
including risks related to preclinical and clinical studies, their
timings and results, and the potential that earlier clinical studies may
not be predictive of future results. A review of these risks can be
found in ImmunoGen's Annual Report on Form 10-K for the year ended
INVESTOR RELATIONS CONTACT