Mirvetuximab Soravtansine Offers New Path Forward for Patients with Frα-Positive Platinum-Resistant Ovarian Cancer

Kathleen Lutz, RN, NP-BC WH

After receiving an accelerated approval in November of 2022, mirvetuximab soravtansine-gynx (Elahere) started to change the tide for patients with platinum-resistant disease after receiving an indication for the treatment of epithelial ovarian, fallopian tube, or primary peritoneal cancers that are folate receptor alpha (Frα) positive.¹ According to Kathleen Lutz, RN, NP-BC WH, the antibody-drug conjugate may prove beneficial for this smaller subgroup of patients who have been heavily pretreated.

The approval was supported by data from the phase 3 SORAYA trial (NCT04296890) where patients (n = 104) achieved an overall response rate (ORR) of 31.7% (95% CI, 22.9-41.6) with a complete response rate of 4.8%. Patients treated with the FRα-directed antibody-drug conjugate experienced a median duration of response (DOR) of 6.9 months (95% CI, 5.6-9.7).²

“These were significant findings because we’re looking at patients with platinum-resistant ovarian cancer,” Lutz said. “As we move forward in treatments we get less of a response over time. So, the 6.9-month median DOR [was] acceptable, [as was] the ORR of 31.7%. These patients are heavily pretreated—the majority had 2 or 3 [prior] lines [of therapy] in the study. So, at this point I’d be happy with that for some of our patients.”

In an interview with Oncology Nursing News®, Lutz, a nurse practitioner at the NYU Perlmutter Cancer Center, discussed the significance of the approval and how finding the right patients who will benefit from the agent will be key. According to Lutz, the introduction of a targeted agent with a median DOR of 6.9 months is a promising option for patients who would otherwise not have many options besides clinical trial enrollment or chemotherapy regimens, although she pointed out that the SORAYA trial did not demonstrate ethnic diversity in terms of patient population.

Moving forward, Lutz noted that she is interested in seeing the population of patients who will be Frα positive as well as BRCA positive. On the SORAYA study, 20% of patients were BRCA positive (14% vs 6% were positive for BRCA1 vs BRCA2, respectively) and 48% had undergone prior treatment with a PARP inhibitor. ² Moreover, she noted that, because the agent also has a box warning for ocular toxicities including visual impairment, keratopathy, dry eye, photophobia, eye pain, and uveitis, and 20% of patients on the trial needed dose reduction due to toxicities,establishing good relations with an ophthalmologist may be key, to be able to refer patients to if necessary.³

Oncology Nursing News®: What stood out to you about the trial data?

Lutz: What came surprising to me was the breakdown of the ethnicity; I look at that on most trials now, race and ethnicity, because we know there’s such a big disparity amongst our different populations and we have a large variety of populations here.

[The trial enrolled] mostly Caucasian women; [96% of patients] were White, 2% were Asian, 2% were not reported, and 2% were Hispanic or Latino. That doesn’t tell us a lot about how [the agent] is going to respond to patients with other ethnicities, that’s definitely a concern of mine, and the numbers are small, but the response rate was good. You have to take it at face value for that in understanding that [but] it’s definitely a good option [for] patients with platinum-resistant ovarian cancer.

[Also those] who had prior PARP [inhibitor treatment and] who had prior bevacizumab [Avastin], [were] interesting numbers. Are we going to find more of the patients with BRCA-positive disease have Frα-positive [tumors]? It just so happens that my 1 patient who was Frα-positive was BRCA1/BRCA2-positive, and that was interesting.

How common is it in your practice to see patients with Frα-positive platinum-resistant disease? Do you anticipate that this treatment will positively impact a decent amount of your patients?

We’re testing everyone across the board for the Frα gene, and out of approximately 8 [patients], I’ve only had 2 positives, so I believe the numbers are going to be small. I’m not sure what will be the biggest population with Frα, but the numbers will be small, and it’s finding the right patient at the right time; now that we’re screening for it ahead of time, we could be more prepared with that as an option if we have a positive patient.

Prior to the approval, what options existed for patients who were platinum resistant and what makes mirvetuximab soravtansine different?

It’s a single-agent drug and it’s well tolerated from what we can tell. Prior to this, if we had a clinical trial, we would enroll patients in that, but they [otherwise] would move to standard-of-care chemotherapy [with] bevacizumab, gemcitabine, [and/or] weekly paclitaxel, some of the more common standard-of-care chemotherapies that you would move to until you knew if they were Frα positive or not.

The schedule [for mirvetuximab soravtansine] is good and overall, [and] it’s going to be well tolerated once we get it going. I haven’t treated anyone [with the agent] yet, [but] it has a lot of positives once we find the right patient.

What do you anticipate being the biggest challenges in treating patients?

The biggest challenge is that many patients are heavily pretreated, 50% of [patients in the trial] had at least 3 prior lines. So they [may] have more toxicity in terms of hematologic toxicities. That’s my biggest worry. Some of the biggest challenges are also getting patients into ophthalmology ahead of time [and] getting them set up with a provider that can see them in a timely fashion.

We are lucky at [NYU Langone] because many of our trials do require ophthalmology evaluations ahead of time. I have a bunch of providers that are getting on board and willing to see our patients. We were lucky to have one of the representatives contact ophthalmologists and get him some of the information that’s needed. Once you get through that part of it and you have everything lined up, it should flow easily because so many of our other trials require eye exams.

References

1. FDA grants accelerated approval to mirvetuximab soravtansine-gynx for FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or peritoneal cancer. FDA. November 14, 2022. Accessed March 13, 2023. bit.ly/3UP742w
2. Matulonis UA, Lorusso D, Oaknin A, et al. Efficacy and safety of mirvetuximab soravtansine in patients with platinum-resistant ovarian cancer with high folate receptor alpha expression: results from the SORAYA Study. J Clin Oncol. Published online January 30, 2023. doi:10.1200/JCO.22.01900.
3. Elahere. Prescribing information; ImmunoGen Inc; 2022. Accessed March 13, 2023. https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761310s000lbl.pdf