IMGN stock is up in after-hours trading on December 19, 2019, as the company continues to attract buyers after it announced on December 17, 2019, an accelerated approval pathway for mirvetuximab soravtansine in ovarian cancer.
mmunoGen Inc., (Nasdaq: IMGN), a leader in the expanding field of antibody-drug conjugates (ADCs) for the treatment of cancer, today announced that the U.S. Food and Drug Administration (FDA) has advised that a new single-arm study in platinum-resistant ovarian cancer could support accelerated approval for mirvetuximab soravtansine. Based on this guidance, the company will initiate SORAYA, a pivotal trial to evaluate mirvetuximab monotherapy in women with folate receptor alpha (FRα)-high platinum-resistant ovarian cancer who have been previously treated with Avastin® (bevacizumab).
“We have engaged in constructive discussions with FDA and evaluated all avenues to bring mirvetuximab to patients more quickly,” said Mark Enyedy, ImmunoGen’s President and Chief Executive Officer. “Having aligned with the agency that women with FRα-high platinum-resistant ovarian cancer that has progressed after prior treatment with bevacizumab require better therapeutic options, we are pleased to advance mirvetuximab in this patient population with SORAYA, which, if successful, would enable us to submit an application for accelerated approval during the second half of 2021. We anticipate enrolling the first patient in SORAYA next quarter and expect top-line data from the study in mid-2021.”
ImmunoGen’s mirvetuximab program now includes two new trials, SORAYA and MIRASOL, which will enroll concurrently.
SORAYA: Pivotal Trial
SORAYA is a single-arm trial with mirvetuximab that will enroll approximately 100 patients. Eligibility criteria include patients with platinum-resistant ovarian cancer whose tumors express high levels of FRα using the PS2+ scoring method, and who have been treated with up to three prior regimens – at least one of which included bevacizumab. The primary endpoint of this study is overall response rate by investigator assessment and the key secondary endpoint is duration of response.
MIRASOL: Confirmatory Trial
MIRASOL is a randomized Phase 3 trial in which 430 patients will be randomized 1:1 to receive either mirvetuximab or investigator’s choice of single-agent chemotherapy (weekly paclitaxel, pegylated liposomal doxorubicin, or topotecan). Eligibility criteria include patients with platinum-resistant ovarian cancer whose tumors express high levels of FRα using the PS2+ scoring method, and who have been treated with up to three prior regimens. The primary endpoint of this study is progression free survival by investigator assessment. The key secondary endpoints include: overall response rate, overall survival, and patient-reported outcomes.
“We have reviewed the data generated from our Phase 1 and FORWARD I studies using the PS2+ scoring method and have identified 70 patients who would meet the key eligibility criteria for SORAYA. The overall response rate in these patients was 31.4% with 95% CI (20.9%, 43.6%) and a median duration of response of 7.8 months with 95% CI (3.98, -),” said Anna Berkenblit, MD, Senior Vice President and Chief Medical Officer of ImmunoGen. “These data compare quite favorably to the response rate seen with single agent chemotherapy in platinum resistant disease, which was 12% in the AURELIA and CORAIL trials, and included patients naïve to and previously treated with bevacizumab.”
Berkenblit continued, “Replicating these data in SORAYA would support an application for accelerated approval in advance of the completion of MIRASOL, which would thereafter provide the randomized data needed for conversion to full approval. We are delighted to advance both studies as soon as possible.”
On December 7, 2019, H.C. Wainwright analyst Debjit weighed in on the news. H.C. Wainwright analyst Debjit Chattopadhyay called ImmunoGen’s agreement with the FDA to expedite the availability of mirvetuximab soravtansine for patients with platinum-resistant ovarian cancer who have experienced disease progression on three prior lines of therapy a “compelling regulatory advance we did not anticipate” and raised his price target on shares to $9 from $5 based on the news. The top-line SORAYA study data are now expected in the first half of 2021, which could lead to a commercial launch mid-2022, which Chattopadhyay said would be about a year ahead of launch estimates. Having an accelerated pathway stems concerns about multiple competitive programs and bolsters confidence in the team, added the analyst, who keeps a Buy rating on ImmunoGen shares.
On December 9, 2019, ImmunoGen announced that new safety and efficacy findings from the dose escalation and expansion of the first-in-human trial of IMGN632 in patients with relapsed/refractory acute myeloid leukemia and blastic plasmacytoid dendritic cell neoplasm were presented in an oral session at the 61st American Society of Hematology Annual Meeting.
Anna Berkenblit, Senior Vice President and Chief Medical Officer of ImmunoGen, said, “With the benefit of a comprehensive assessment of IMGN632’s safety and efficacy across a wide range of doses and two schedules, we have selected a dose and schedule that demonstrate significant anti-tumor activity, favorable tolerability, and the convenience of a short infusion that can be administered in an outpatient setting. Together with the preclinical data on combining IMGN632 with azacitidine and venetoclax presented by our collaborators from MD Anderson, these updated clinical results provide a strong foundation for our ongoing expansion of IMGN632 monotherapy studies in BPDCN, AML, and ALL, and the recent initiation of our trial to evaluate IMGN632 combinations with azacitidine and venetoclax in relapsed and frontline AML, as well as IMGN632 as a monotherapy in minimal residual disease positive AML patients.”
Naval Daver, Associate Professor in the Department of Leukemia at MD Anderson Cancer Center, added: “We are particularly encouraged by the activity and tolerability of IMGN632 in heavily pre-treated patients, including a 40% ORR in relapsed and refractory de novo AML patients treated at the recommended phase 2 dose, and the responses in relapsed or refractory BPDCN patients previously treated with Elzonris and intensive chemotherapy. We look forward to continuing to evaluate IMGN632 as a monotherapy and in combination with azacitidine and venetoclax in doublet and triplet regimens in relapsed/refractory AML and frontline older AML.”