Data backs GSK's ovarian cancer blockbuster hopes
GSK has reported positive clinical results with an antibody-drug conjugate licensed from China's Hansoh Pharma in 2023, delivering an early fillip for new chief executive Luke Miels.
The phase 1 BEHOLD-1 trial of B7-H4-directed mocertatug rezetecan (Mo-Rez, formerly HS-20093) showed an objective response rate (ORR) of 62% in platinum-resistant ovarian cancer (PROC) and 67% in recurrent or advanced endometrial cancer – two diseases that currently have limited treatment options.
Armed with the encouraging results, which were presented at the Society of Gynaecologic Oncology (SGO) Annual Meeting on Women's Cancer in San Juan, Puerto Rico, GSK is pressing the accelerator on the project with five phase 3 trials due to start this year in various ovarian and endometrial cancer settings.
The readout comes a couple of years after GSK paid $85 million upfront for rights to Mo-Rez outside China, Hong Kong, Macao, and Taiwan, with another $1.5 billion in success-based milestones.
It was the first of two ADCs that the UK-headquartered pharma group has licensed from Hansoh after B7-H3-targeted risvutatug rezetecan for small cell lung cancer (SCLC) and other solid tumours, which was the subject of a $1.7 billion agreement also signed in 2023.
GSK sold off its oncology assets more than a decade ago, but returned to the sector under previous chief executive Emma Walmsley, with Miels now leading the charge with four approved therapies and 13 in clinical development.
GSK has set a peak annual sales target of £2 billion ($2.7 billion) for Mo-Rez, which is viewed as a key part of its strategy to grow its yearly revenues to £40 billion or more by 2031, up from less than £33 billion in 2025.
"Treatment of gynaecological cancers remains a major challenge, with a pressing need for new therapies that offer improved response rates," said Hesham Abdullah, GSK's global head of cancer R&D. "With Mo-Rez we now have compelling evidence of a promising clinical profile."
AbbVie's Elahere data
There was more encouraging news for ovarian cancer patients from the SGO congress after AbbVie reported the results of the phase 2 IMGN853-042 trial of its first-in-class, FRα-targeting ADC Elahere (mirvetuximab soravtansine) in heavily-pretreated patients with recurrent platinum‑sensitive ovarian cancer (PSOC) whose tumours express FRα.
The fast-growing product – which has been approved for FRα-positive PROC since 2022 and made $690 million in global sales last year – achieved an ORR of 62.7% when given alongside carboplatin in an initial regimen, followed by Elahere on its own as a continuation therapy.
"Despite being considered chemotherapy-responsive […] PSOC remains challenging to treat," said Daejin Abidoye, AbbVie's therapeutic area head for oncology, solid tumour and haematology.
"With each recurrence, responses to standard platinum-based chemotherapy often diminish and patients may experience cumulative toxicities," he added. "These results are encouraging and further support the potential of [Elahere] in PSOC as a novel treatment regimen."
AbbVie is also running a phase 3 trial, called GLORIOSA, of Elahere in combination with bevacizumab versus bevacizumab alone as maintenance therapy for patients with FRα-expressing PSOC.
FRα is considered a marker of tumour aggressiveness, associated with poorer response rates to treatment, and is over-expressed in around a third of ovarian cancer patients.
GlobalData has previously predicted that, with its first-to-market advantage, Elahere could generate sales of $2.8 billion in 2029.
