Chemotherapy is one of the most potent tools for fighting ovarian cancer, but sometimes the cancer proves stubbornly resistant to the most popular chemo drugs. In these cases, however, there are other options for treatment.
What is a Platinum Resistant Tumor?
A cancer that comes back within six months of treatment with a platinum-based chemotherapy drug is called platinum resistant. If a cancer returns after 6 months following platinum-based chemotherapy is complete, it’s called platinum sensitive, and is considered easier to treat.
Read MoreOptions For Women With Platinum Resistant Tumors
Rimel says that a woman who is dealing with platinum resistant ovarian cancer should start by having a very frank conversation with her doctor about what the options that are available to her for treatment and what her goals should be with that treatment.The patient with platinum resistant ovarian cancer has options for chemotherapy, with or without bevacizumab (aka Avastin), that patient may also choose to be a part of a clinical trial, whether that clinical trial uses immunotherapy or other novel agents, a patient with platinum disease may also be on bevacizumab long term for reduction in the amount of tumor she has. There are lots of different options.
There are some studies looking at platinum resistant patients with PARP inhibitors and data suggests there is a small population of patients that will benefit from that PARP inhibitor.
However, Rimel says that right now, doctors and researchers are unclear about who those patients are exactly, so they aren't sure how widespread the benefit would be from that kind of treatment.
There are published studies that say that agents like bevacizumab (Avastin) can be particularly useful in combined therapy such as a studied published on PubMed.gov as a part of the US National Library of Medicine at the National Institutes of Health.
This combination had been used in several different clinical trials in the past. Clinical trials are important for the advancement of treatment options for women with ovarian cancer. The National Ovarian Cancer Coalition offers a listing of outside resources for clinical trials. Their page includes a list of clinical trial sites as well as resources for caregiver support.
New Developments
In 2023, a drug called Elahere (generic name mirvetuximab soravtansine) was given emergency approval by the Food and Drug Administration (FDA). Phase III clinical trials showed that the drug was effective at treating some patients who had become resistant to platinum-based chemotherapies.
The drug targets the folate receptor alpha (FRα) protein present on the tumor cell surface. The accelerated approval was based on a rigorous clinical trial called SORAYA, which showed effectiveness at suppressing cancer growth in at least one-third of patients.
The drug is expected to be given full approval in the U.S. after promising new data from another trial, MIRASOL, was released in May 2023.
The MIRASOL trial looked at how it performed compared to giving chemotherapy alone in patients with folate receptor alpha (FRα)-positive platinum-resistant ovarian cancer.
In the trial, more than one-third of patients (36%) receiving Elahere (who had previously been treated with bevacizumab) experienced improved progression-free survival (how long a patient goes without their disease worsening) and more than one-fourth (26%) experienced improved overall survival (how long the patient lives).
In another, smaller group of patients who had not previously been treated with bevacizumab, progressional free survival was 34% better and overall survival was 49% better than when patients received standard chemotherapy.
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