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Serplulimab is now the only anti–PD-1 monoclonal antibody approved by the MHRA for patients with extensive-stage small cell lung cancer in the first line.
Serplulimab in extensive-stage small cell lung cancer|
Image Credit: Ashling Wahner & MJH Life Sciences Using AI
The United Kingdom’s (UK) Medicines and Healthcare products Regulatory Agency (MHRA) has granted approval to the anti–PD-1 monoclonal antibody serplulimab (Hetronifly) for the treatment of adult patients with previously untreated, metastatic extensive-stage small cell lung cancer (ES-SCLC).1
This approval follows a similar regulatory decision announced in India the same week, bringing the total number of countries and regions where serplulimab is approved to over 40, including the European Union, China, Indonesia, and Singapore.
"As the first and only anti-PD-1 monoclonal antibody approved in the UK for small cell lung cancer [SCLC], this marks an important new treatment option for patients with this aggressive type of lung cancer who currently have limited choices and face a poor prognosis,” Julian Beach, interim executive director of Healthcare Quality and Access at the MHRA, stated in a news release.
Paul Tredwell, executive vice-president EMENA of Accord Healthcare, added that, "The MHRA's approval of [serplulimab] provides a new treatment option in the fight against ES-SCLC— one of the most aggressive forms of lung cancer. This milestone reflects our ongoing commitment to providing novel specialty medicines for difficult-to-treat conditions."
Serplulimab has received regulatory approval in China and several Southeast Asian countries for the first-line treatment of patients with ES-SCLC. In addition to ES-SCLC, China’s National Medical Products Administration has approved serplulimab for the treatment of squamous non–small cell lung cancer (NSCLC), nonsquamous NSCLC, and esophageal squamous cell carcinoma. Both the FDA and the European Commission (EC) have granted orphan drug designation to serplulimab for the treatment of patients with SCLC.
Notably, on February 5, 2025, the European Commission (EC) approved serplulimab plus chemotherapy for the frontline treatment of adult patients with ES-SCLC.2
Findings from the double-blind, international, multicenter phase 3 ASTRUM-005 trial (NCT04063163) have primarily supported these regulatory decisions. In this study, serplulimab plus chemotherapy elicited a significant overall survival (OS) benefit compared with placebo plus chemotherapy in the first-line setting in patients with ES-SCLC.3
The randomized, double-blind, phase 3 trial enrolled patients who were at least 18 years old with histologically or cytologically confirmed ES-SCLC, no prior systemic therapy, at least 1 measurable lesion per RECIST 1.1 criteria, and an ECOG performance status of 0 or 1.
Patients were randomly assigned 2:1 to receive 4.5 mg/kg of serplulimab on day 1 plus carboplatin at an area under the curve of 5 on day 1 and 100 mg/m² of etoposide on days 1 through 3 every 3 weeks for up to 4 cycles. This was followed by maintenance serplulimab at a dose of 4.5 mg/kg every 3 weeks; or placebo plus the same chemotherapy regimen, followed by placebo maintenance. Stratification factors included PD-L1 expression level (negative vs positive vs not evaluable), brain metastases (yes vs no), and age (younger than 65 years vs 65 years or older).
The study’s primary end point was OS. Secondary endpoints included progression-free survival (PFS), time to second progression, overall response rate (ORR), duration of response (DOR), safety, pharmacokinetics, immunogenicity, biomarker analyses, and quality of life.
Updated data from the end-of-study analysis, presented at the 2025 ASCO Annual Meeting, demonstrated that patients in the serplulimab arm (n = 389) achieved a median OS of 15.8 months (95% CI, 13.9–17.4) vs 11.1 months (95% CI, 10.0-12.4) in the placebo arm (n = 196; HR, 0.60; 95% CI, 0.49-0.73; descriptive P < .001). Four-year OS rates were 21.9% (95% CI, 17.6%-26.6%) and 7.2% (95% CI, 3.8%-12.1%), respectively. Median PFS per blinded independent central review was 5.8 months (95% CI, 5.6-6.9) with serplulimab vs 4.3 months (95% CI, 4.2-4.4) with placebo (HR, 0.47; 95% CI, 0.38-0.57; descriptive P < .001).
The confirmed ORR was 68.9% (95% CI, 64.0%–73.5%) with serplulimab and 58.7% (95% CI, 51.4%-65.6%) with placebo. Partial responses were observed in all responders in the control arm; 2.3% of serplulimab-treated patients achieved a complete response. Median DOR was 6.8 months (95% CI, 5.5-7.9) vs 4.2 months (95% CI, 3.1-4.2), respectively (HR, 0.45; 95% CI, 0.35-0.58; descriptive P < .001).
Serplulimab's safety profile was consistent with prior reports. Treatment-emergent adverse effects (TEAEs) occurred in 96.4% of patients in the serplulimab arm and 98.0% in the placebo arm. Grade 3 or higher TEAEs were reported in 84.8% vs 83.2%, respectively, with hematologic toxicities being most common.
A head-to-head bridging trial comparing serplulimab with atezolizumab (Tecentriq), the current frontline standard of care for patients with ES-SCLC in the US, is currently ongoing.1 This trial is planned to support the FDA approval of serplulimab in the US.
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