For a woman being treated for ovarian cancer, it’s good news for her cancer to be deemed "Platinum Sensitive." That means that her disease is responding to platinum-based chemotherapy treatment and can continue to benefit from the therapy.
It also means the woman can continue being treated with the therapy should a recurrence of the cancer occur.
What is Platinum Sensitivity?
Read MorePlatinum-based Options
The most commonly used Platinum chemotherapy in ovarian cancer is Carboplatin, which is often combined with other non-Platinum drugs including Taxol, Doxorubicin (also known as Doxil) or Gemzar.Women with Platinum-Sensitive ovarian cancer can expect any platinum-based drugs to have an effect on their tumor, even as a second or third treatment. You may hear doctors call this second or third “line” treatment.
Options for Women Who Are Platinum Resistant
In the case of a Platinum-Resistant patient, a doctor might increase the dosage of Taxol, such as administering it weekly instead of every three weeks. Doctors may also use additional drugs such as Gemzar or Doxil.
Any of those drugs would likely combine with the non-platinum drug Bevacizumab, known commercially as Avastin. This drug is a VEGF (Vascular Endothelial Growth Factor) inhibitor, which works by targeting the protein repair process, instead of DNA repair. Blocking the VEGF protein repair process can stop blood vessel growth, which can deny a malignancy oxygen and therefore cut off its development. This process is known as anti-angiogenesis: blocking the physiological process through which new blood vessels are formed out of ones already in existence.
Avastin is particularly helpful for women with high-risk cases of ovarian cancer. This includes:
- Widely metastatic cases that could have spread to the other areas, such as the liver and chest.
- Cases where a tumor cannot be fully removed surgically.
- Women with recurrent ovarian cancer.
The drug has had a meaningful effect on recurrent cases that are both Platinum sensitive (six months after Platinum-based treatment) and Platinum resistant (within six months of Platinum-based treatment).
Women can continue using Avastin alone as maintenance after chemotherapy, as long as cancer doesn't recur and the patient tolerates the drug well.
Currently in the U.S., over 250,000 women in the U.S. have ovarian cancer. Over 22,000 women in the U.S. are projected to be diagnosed with ovarian cancer in 2019. Ovarian cancer mainly affects older women. Women aged 63 or older make up roughly half ovarian cancer diagnoses.
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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