This was the outcome of an international clinical study (phase 3) among 391 patients. Two thirds of the patients received the medication olaparib as maintenance cure after their first chemotherapy, and one third received a placebo. This is the SOLO-1 study.
Gabe Sonke was in the steering group of the study and contributed to the article.
On Sunday 21 October, an article reporting these results was published in the New England Journal of Medicine. The study was also one of the highlights at the ESMO conference in Munich, the annual meeting of the European Society for Medical Oncology held at the end of October.
Sonke says he is pleasantly surprised by the results. Asked about the importance of the study, he says: 'Knowing this now leads to better treatment and, possibly, better chance of recovery for women with ovarian cancer involving a BRCA mutation.'
Ovarian cancer (ovarian carcinoma) is a type of cancer that is often discovered late and is therefore difficult to cure. The first steps of the treatment plan are surgery and chemotherapy. This works in many cases, but the cancer often comes back, usually within two years. And then ovarian cancer can no longer be cured.
Recently, the drug olaparib has been added to the treatment options for ovarian cancer. It is a so-called targeted medicine that directly affects a protein in the cancer cell.
Olaparib, developed by scientists from Cambridge, inhibits the action of the protein PARP in the cancer cell. That protein fixes broken tumour DNA, allowing the tumour cell to divide unhindered again. Olaparib ensures that PARP does not get this chance to repair and thus counteracts tumour growth. The drug works best in patients with an error in the BRCA1 and BRCA2 gene, which is 15-20% of all patients with ovarian cancer. Due to a defect in these genes, cells develop mutations very quickly, the hallmark of cancer cells.
Olparib (brand name Lynparza) has already been approved in the EU and the US as maintenance treatment for ovarian cancer that has returned or metastasized. Sonke expects, after the new results now published in the New England Journal of Medicine, that olaparib will also be approved as part of the initial treatment, supplementary to surgery and a first chemotherapy, to try to prevent ovarian cancer from returning and metastasizing.
The most common side effect of olaparib in the SOLO1 study was anaemia. 6.5% of the patients who received the medicine suffered from this. This did not occur in the control group that received a placebo.
The SOLO-1 study has been completed. Patients are still being monitored for longer-term follow-up data. However, research into the effects of olaparib in ovarian cancer continues. In the Netherlands Cancer Institute, the answers to two questions are now being sought:
- We have now demonstrated the effect of olaparib for women with a BRCA mutation. But can we also demonstrate this for the broader population of ovarian cancer patients?
- What are the effects of olaparib if you combine it with immune therapy? This is now being studied in the Mediola study, an international phase I/II study in which various Dutch centers are participating, including the Netherlands Cancer Institute.
Important steps were also taken in the fundamental research into PARP inhibitors last year. For example, researchers from the AVL research group run by Jos Jonkers are increasingly understanding how cancer cells become resistant to PARP inhibitors. Resistance to this type of new generation medication is an important next hurdle.
The SOLO-1 study in brief:
- Treatment:
Maintenance therapy with PARP inhibitor (Olaparib) after chemotherapy as part of a first-line treatment
- For whom:
Women with newly diagnosed ovarian cancer at an advanced stage with aBRCA1/2 gene mutation who have had their surgery and a first treatment with chemotherapy.
- Type of study:
Phase 3, randomized, double-blind, with placebo group, international (15 countries). In the Netherlands, AVL and UMC Maastricht took part.
- Number of patients:
391, 9 of whom were in the Netherlands Cancer Institute.
- Sponsor:
AstraZeneca
- Open or closed?
The study has been completed.
Are you a patient and do you think you are eligible to participate in a study? If so, discuss this with your doctor.
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