Lurbinectedin (Zepzelca) Approved for
Metastatic SCLC

Zosia Chustecka

June 16, 2020

Patients with metastatic small cell lung cancer (SCLC) whose disease has progressed after or during treatment with platinum-based chemotherapy now have a new option to try — lurbinectedin (Zepzelca, Jazz Pharma/PharmaMar).

The drug was granted an accelerated approval by the US Food and Drug Administration (FDA) for this use on data showing overall response rate and duration of response.  Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial, the company notes.

"Small cell lung cancer is a disease with limited treatment options," said Bruce Cozadd, chairman and CEO of Jazz Pharmaceuticals. "While patients may initially respond to traditional chemotherapy, they often experience an aggressive recurrence that is historically resistant to treatment."

"Seeing first-hand the aggressive nature of SCLC and knowing that the large majority of those diagnosed will experience relapse, I am excited to see an effective new treatment demonstrating durable responses," Jeff Petty, MD, oncology specialist, Wake Forest Baptist Health, Winston-Salem, North Carolina, commented in the company press release. This new drug "is an important and much-needed addition to the treatment landscape for relapsing SCLC," he added.

Approval Based on Monotherapy Trial

The approval is based on a monotherapy clinical trial in 105 patients, which was published in May in Lancet Oncology, with first author José Trigo, MD, from the Hospital Universitario Virgen de la Victoria in Malaga, Spain.  

These were adult patients with both platinum-sensitive and platinum-resistant SCLC who had disease progression after treatment with platinum-based chemotherapy. They were treated at 26 hospitals across six European countries and the US. All patients received lurbinectedin 3.2 mg/m2 by intravenous infusion over 1 hour. Median follow-up was 17.1 months.

Overall response by investigator assessment was seen in 37 (35.2%) of the 105 patients. The response was greater (at 45%) among the patients with sensitive disease and smaller (22.2%) among those with resistant disease.

Lurbinectedin demonstrated a median duration of response of 5.3 months as measured by investigator assessment.

In a post-hoc analysis, among the 37 patients who had an initial objective response, the median overall survival was just over 1 year (12.6 months), but was even longer among patients who had platinum-sensitive disease (15.8 months), although it was shorter in patients with resistant disease (10.9 months).

These data are "particularly encouraging," comment the authors of an accompanying editorial, led by Oscar Arrieta, MD, from the Thoracic Oncology Unit at the Instituto Nacional de Cancerología in Mexico City, Mexico. These response rates "outperform all previous results achieved with topotecan and other less established treatment schemes including cyclophosphamide, doxorubicin, and vincristine, or platinum re-challenge, in this setting."

"Lurbinectedin represents an innovative approach to conventional anti-cancer drugs, with an elegant mechanism of action based on the inhibition of transcription-dependent replication stress and genome instability of tumor cells," the editorialists comment. "The drug binds to specific DNA triplets commonly found in transcription sites and triggers cellular apoptosis."

"At present, the only evidence-based second-line treatment approved for SCLC is topotecan, a topoisomerase 1 inhibitor with moderate activity in patients with sensitive disease, although its effect is much less evident in patients with resistant SCLC," they continue.

"Overall, the study by Trigo and colleagues presents novel data for a very challenging disease for which few treatment options exist, and the data on response and survival do seem to outperform data from historical controls," Arrieta and colleagues write.

The editorialists also note that in this trial a few patients had received immunotherapy as part of the first line treatment, and some of these patients (5 of 8 patients, 68%) had "an outstanding rate of durable response to lurbinectedin." This raises the possibility of a synergistic effect between immunotherapy and lurbinectedin, as the combination that seems to enhance immune memory and impair subsequent tumor growth, they add. Further trials will need to explore sequencing of therapy, they suggest.

A large phase 3 study known as ATLANTIS is currently underway.  

The most common grade 3-4 adverse events were hematologic abnormalities: anemia (9% of patients), leukopenia (29%), neutropenia (46%), and thrombocytopenia (7%). Serious treatment-related adverse events occurred in 10% of patients, of which neutropenia and febrile neutropenia were the most common (5% each). No treatment-related deaths were reported.

The study was funded by PharmaMar. Trigo and coauthors, and Arrieta and fellow editorialists, all report relationships with pharmaceutical companies, as detailed in the published articles.

Lancet Oncol. Published May 1, 2020. Abstract, Editorial

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