ROSELLA Study Types Deliver Breakthrough: Relacorilant Passes OS Test in Ovarian Cancer

Corcept Therapeutics reported a significant victory on January 22, 2026, when its experimental drug relacorilant achieved a primary endpoint in the ROSELLA trial, sending its stock soaring 13.7%. The phase III ROSELLA study successfully demonstrated that combining relacorilant with nab-paclitaxel chemotherapy significantly extends survival in patients with platinum-resistant ovarian cancer compared to chemotherapy alone.

ROSELLA Trial Framework: How Relacorilant Demonstrated Survival Benefit

The ROSELLA study represents a comprehensive evaluation of relacorilant across different patient types and disease presentations within the platinum-resistant ovarian cancer population. This multi-pronged study design evaluated whether the combination therapy could deliver meaningful clinical benefits while maintaining a manageable safety profile.

The trial’s dual primary endpoints—progression-free survival (PFS) and overall survival (OS)—were both achieved, a notable accomplishment in oncology research where meeting both objectives is frequently challenging. The study encompassed multiple patient types at varying disease stages, allowing researchers to assess the therapy’s consistency across diverse populations with platinum-resistant disease.

Clinical Results: Median OS Achievement and Risk Reduction

The ROSELLA data painted a compelling picture for the combination approach. Patients receiving relacorilant plus nab-paclitaxel achieved a median overall survival of 16 months, compared to 11.9 months for those receiving chemotherapy alone. This translated to a 35% reduction in the risk of death, providing quantifiable evidence of the therapy’s clinical value.

Notably, this survival benefit came without compromising safety. The combination demonstrated a tolerability profile consistent with nab-paclitaxel monotherapy, meaning patients didn’t face an increased burden of adverse effects. This balance between efficacy and safety is particularly important in treating platinum-resistant ovarian cancer, where patients often have limited treatment options and may already be dealing with side effects from prior therapies.

The consistent performance across different patient types underscored the broad applicability of this combination approach. The study didn’t require biomarker selection, meaning the therapy showed benefit across the general platinum-resistant ovarian cancer population without need for genetic or molecular testing to identify responsive patients.

Regulatory Path Forward: FDA Decision Timeline

The positive ROSELLA data set the stage for accelerated regulatory progress. The FDA accepted a new drug application (NDA) for relacorilant in combination with nab-paclitaxel in September 2025, with a regulatory decision expected on July 11, 2026. Additionally, Corcept submitted a marketing authorization application to the European Medicines Agency (EMA), with a European decision anticipated later in 2026.

Beyond the platinum-resistant indication, relacorilant is being evaluated in broader oncology settings. The phase II BELLA study is examining relacorilant combined with both nab-paclitaxel and Roche’s Avastin (bevacizumab) in platinum-resistant ovarian cancer, exploring whether triple combination therapy offers patients additional benefits. Relacorilant is also being studied for platinum-sensitive ovarian cancer, endometrial cancer, cervical cancer, pancreatic cancer, and prostate cancer.

Balancing Act: ROSELLA Success Against Earlier Setbacks

While the ROSELLA triumph represents a major positive catalyst, recent developments have tempered investor enthusiasm. In late 2025, the FDA issued a complete response letter (CRL) to a separate NDA seeking approval for relacorilant in Cushing’s syndrome (hypercortisolism). Despite the GRACE study meeting its primary endpoint and the confirmatory GRADIENT trial supporting those findings, the FDA determined that additional effectiveness evidence was required before approving the drug for this indication.

This regulatory setback delayed progress on a potentially important growth driver for Corcept. The company’s current commercial portfolio relies heavily on Korlym, its sole marketed drug for Cushing’s syndrome. In the first nine months of 2025, Korlym generated $559.3 million in sales, up 13.4% year-over-year, demonstrating strong demand but also highlighting the company’s dependence on a single product.

Market Implications and Investment Outlook

The ROSELLA OS success shifts investor focus toward oncology as Corcept’s growth engine, potentially diversifying the company’s revenue streams beyond endocrinology. The over-the-counter market for Korlym remains solid, but relacorilant’s potential approval in platinum-resistant ovarian cancer—a large indication with significant unmet medical need—could meaningfully expand the company’s market position.

However, the stock’s 40% decline over the past six months reflects investor concerns about the Cushing’s syndrome setback and broader market volatility in the biotech sector. The upcoming FDA decision in July 2026 will be critical in determining whether the ROSELLA breakthrough can revitalize Corcept’s growth trajectory and restore investor confidence.