Lurbinectedin, a drug developed by Zeltia unit PharmaMar and mined from the ocean’s depths, has improved survival for patients with advanced ovarian cancer, adding months of life in this hard-to-treat patient population.

“The response rate was especially impressive in patients with platinum resistance,” said Andres Poveda of the Fundacion Instituto Valenciano de Oncologia in Spain, reporting results of a Phase II trial at the American Society of Clinical Oncology meeting in Chicago.

Lurbinectedin started life as a preparation derived from the otherwise unremarkable sea squirt. Although originally characterised as a potential anticancer agent in the late 60s, clinical study was initially hampered by the inability to produce enough drug (roughly a ton of squirt per five grammes of active agent). Eventually, chemists isolated and synthesised the parent compound, called trabectedin, which was developed by PharmaMar and is marketed in Europe as Yondelis.
However, the activity for trabectedin was seen by some observers as modest at best. After replacing a functional group on the parent compound, a new and improved molecule, lurbinectedin, was born, and is now undergoing trials.

Dr Poveda’s study looked at 81 patients with platinum-resistant/refractory ovarian cancer patients treated with lurbinectedin, or the current standard of care, the taxane topotecan. Response rates with the latter are in the order of 10-15% with no change in overall survival.

Results for lurbinectedin are much better: the overall response rate in this study was 54% in patients with platinum resistance, and progression-free survival was 5.7 months, versus 1.7 months for patients treated with topotecan.   

As for overall survival, the rate was 8.3 months for topotecan, and at the time of reporting at ASCO, the OS for the lurbinectedin cohort had yet to be reached. The treatment was well tolerated, except for some gastrointestinal side effects, which were considered manageable.

Commenting on the results, Paul Haluska at the Mayo Clinic underlined the unmet medical need in this patient population. “Disease progression is nearly universal in these patients and platinum resistance is the final outcome. Drugs with new mechanisms of action may be key to overcoming resistance to current agents – and this mechanism of this drug varies from currently approved therapies for ovarian cancer, so this is very exciting data.”