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March 5, 2024
Clinical Relevance: Elahere’s FDA approval marks a significant advancement in treating advanced ovarian cancer, offering a new, effective option for patients who have exhausted other treatments.
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Since the FDA’s approval of Elahere (mirvetuximab soravtansine), a groundbreaking treatment for specific advanced ovarian cancers, oncologists have had time to consider its role in clinical practice. Representing the first major advancement in nearly a decade, oncologists can now offer some hope to their patients unresponsive to platinum chemotherapy.
“FDA approval of this drug gives us an exciting new treatment option for patients with folate receptor alpha (FRα)-positive, platinum resistant ovarian cancer and really shows the importance of biomarker-driven clinical trials in this disease.” Dr. Melissa Geller, an associate professor in the department of obstetrics, gynecology and women’s health, division of gynecologic oncology at the University of Minnesota, tells SurvivorNet.
Mechanism of Action
Elahere is an antibody-drug conjugate (ADC), a class of highly targeted pharmaceutical drugs designed for cancer therapy. ADCs consist of an antibody linked to a biologically active cytotoxic (cancer-killing) drug.
The antibody specifically targets and binds to antigens present on the surface of cancer cells, delivering the cytotoxic drug directly to the tumor. This targeted approach allows for the selective killing of cancer cells while minimizing damage to normal, healthy cells, potentially reducing side effects compared to traditional chemotherapy.
Elahere’s mechanism is designed to exploit the targeting capability of antibodies combined with the cancer-killing effect of the drug it carries, aiming to provide a more effective and safer treatment option for patients.
“Treatment with the FRα-targeted antibody-drug conjugate mirvetuximab soravtansine-gynx benefited patients with FRα-high, platinum-resistant ovarian cancer, even after multiple lines of prior therapy with highest responses seen when the drug is used as a first-line treatment for platinum resistant ovarian cancer,” Dr. Geller says.
Clinical Evidence
Approval for Elahere (mirvetuximab soravtansine) was based on the results from the SORAYA and MIRASOL trials.
Evaluated the safety and efficacy of Elahere in FRα-high platinum-resistant ovarian cancer patients who received one to three prior therapies, including bevacizumab.
- Objective Response Rate (ORR) was 32.4%, including 5 complete responses and 29 partial responses.
- Median duration of response: 6.9 months.
- Subgroup analysis showed an ORR of 35.3% in patients with one to two prior therapies, 30.2% for those with three prior therapies, 38.0% in patients previously exposed to poly ADP-ribose polymerase inhibitors, and 27.5% in patients without such prior exposure.
Compared Elahere to investigator’s choice of single-agent chemotherapy in FRα-positive platinum-resistant ovarian cancer patients who received up to three prior regimens.
- Median OS was 16.46 months in the Elahere arm, compared to 12.75 months in the IC chemotherapy arm, representing a 33% reduction in the risk of death with Elahere compared to IC chemotherapy.
- Statistically significant and clinically meaningful improvement in PFS by investigator assessment compared to IC chemotherapy, with a hazard ratio of 0.65 (p<0.0001), which represents a 35% reduction in the risk of tumor progression or death with Elahere compared to IC chemotherapy arm (5.62 months versus 3.98 months).
- ORR was 42.3%, including 12 complete responses (CRs), compared to 15.9%, with no CRs, with IC chemotherapy.
In both trials, Elahere had a favorable profile with manageable adverse events. The drug was associated with fewer side effects than many other chemotherapy drugs but a big concern doctors look out for is how it can damage eyesight.
“Common side effects were GI related and low grade ocular events. These side effects did not significantly impact patients or lead to discontinuation of treatment. Treatment discontinuation can be considered for severe ocular toxicity,” notes Dr. Mariam Al Hilli, an obstetrician-gynecologist with the Cleveland Clinic’s Obstetrics & Gynecology Institute.
Candidate testing
Marta A. Crispens, MD, is director, division of gynecologic oncology at Vanderbilt University Medical Center recommends tumor testing for FRα.
Dr. Crispens goes on to say that eligibility for Elahere depends on having exceptionally high levels (exceeding 75%) of the FRα protein. If there is not very much of the protein, Elahere is less likely to work.
While research suggests that roughly 80% of both new and recurring ovarian cancers might have this protein, only around 35-40% of cancers resistant to platinum treatment exhibit such high levels.
“It’s a very specific test something called immunohistochemistry where they can basically take an antibody put it on the slide that has the cancer on it or a slice of the cancer on it and see what percentage the cells are FRα and that’s how they determine eligibility for Elahere,” she says.
You may order a freeimmunohistochemistry (IHC) test through either the FR-ASSIST program or the Labcorp FR-ASSIST™ program if your patient meets the following criteria:
- Have ovarian, fallopian tube, or peritoneal cancer
- Will receive treatment in the US or a territory
- Have not received prior test
- You deem it medically necessary