Afami-cel Receives Full FDA Approval, Expanded Indication to Treat Pediatric Patients With Synovial Sarcoma

The FDA granted full approval of afamitresgene autoleucel (afami-cel, Tecelra; Adaptimmune LLC) and expanded its indication to include pediatric patients 12 years of age and older with unresectable or metastatic synovial sarcoma (SS) who received prior chemotherapy, are HLA-A*02:01P, -A*02:02P, -A*02:03P, or -A*02:06P positive, and whose tumor expresses the MAGE-A4 antigen as determined by FDA-approved or cleared companion diagnostic devices. In August 2024, afami-cel became the first engineered T-cell therapy for a solid tumor cancer to receive accelerated FDA approval in the US.¹

"Today's approval marks an important milestone not only for US WorldMeds, but for the synovial sarcoma community," Breck Jones Sr, founder and CEO of US WorldMeds, said in the news release. "With the transition to full approval, [afami-cel] continues to represent an important treatment option for appropriate patients with biomarker-eligible, advanced SS. This approval is supported by additional clinical evidence which may provide physicians, patients, and families with confidence as they consider treatment decisions. The expansion to include patients as young as 12 years old further broadens access to this personalized approach."¹

What is Afami-cel and Its Mechanism of Action?

Afami-cel is an autologous CD4+ and CD8+ T-cell therapy engineered with a lentiviral vector to express an enhanced-affinity MAGE-A4-specific T-cell receptor (TCR) that recognizes MAGE-A4 peptides presented by multiple common HLA-A2 alleles.²

The TCR is a transmembrane receptor on T cells that recognizes antigens bound to major histocompatibility complexes, triggering an immune response. MAGE-A4, a cancer-testis antigen expressed in several solid tumors SS, is normally limited to germ cells of the testicles and placenta, making it an attractive therapeutic target. MAGE-A4 regulates cell growth, the cell cycle, and apoptosis through p53-related genes and can be processed into antigenic peptides that form complexes with HLA molecules, further supporting its use in TCR-based therapies.²

Treatment consists of lymphodepletion with fludarabine and cyclophosphamide followed by a single intravenous (IV) infusion of 2.68×10⁹ to 10×10⁹ MAGE-A4 TCR-positive T cells on day 1, with acetaminophen and an H1-antagonist given as premedication 30 to 60 minutes before infusion. Experts recommend that systemic corticosteroids are avoided because they can induce T-cell apoptosis and interfere with afami-cel's mechanism of action.² A health care provider will perform tests to see if afami-cel is right for each patient.¹

"What sets [afami-cel] apart is that it is personalized to each individual, engineering a patient's own T-cells to detect, target, and attack their cancer. Until today, that option was only available to adults," Kristen Gullo, senior vice president of US WorldMeds explained in the news release. "For patients 12 years of age and older with biomarker-eligible, advanced SS, today's decision opens the door to a new treatment approach that was previously out of reach and offers hope where options have been extremely limited."¹

Clinical Data Supporting Afami-cel’s Full Approval

The full FDA approval and expanded indication for afami-cel was based on results of the SPEARHEAD-1 study (NCT04044768)³, an open-label, single-arm phase 2 clinical study, which included 137 patients with HLA-A*02 eligible and MAGE-A4 positive patients with metastatic or inoperable SS. Specifically, the approval was based on data that came from cohorts 1, 2, and 3 in the trial. The trial’s primary efficacy outcome was overall response rate (ORR) determined by independent review and supported by duration of response.^1,3

According to the findings, afami-cel treatment resulted in an ORR of approximately 43.8% with a complete response rate of 3.6%. The median duration of response was about 5.3 months (95% CI, 4.5-8.2). Among patients who were responsive to the treatment, approximately 31.9% had a duration of response (DOR) of 24 months or longer.¹

These findings are consistent with earlier findings, which demonstrated an ORR of about 39% in patients with SS, all of whom had partial responses. Most patients (52%) had stable disease, with only 9% having progressive disease. The median time to first response was about 4.9 weeks (95% CI, 4.3-8.1), with the median DOR being 11.6 months (95% CI, 4.4-18). The median progression-free survival was 3.8 months (95% CI, 2.6-6.4) with median overall survival not yet reached at a follow-up of 27.8 months (95% CI, 15.4-not evaluable).²

"For children as young as 12 [years of age] with advanced SS, treatment options have been limited and navigating care decisions can be challenging," said Amy Armstrong, MD, Associate Professor of Pediatrics at Washington University School of Medicine in St. Louis and Director of the Solid Tumor Program at Siteman Kids at St. Louis Children's Hospital. "The availability of an engineered cell therapy for adolescents introduces an important new option for patients who are biomarker-eligible, allowing us to incorporate this approach into treatment planning based on the same evidence that has guided adult care. This is a meaningful step forward for the field."¹

REFERENCES

1. US WorldMeds® Receives Full U.S. FDA Approval of TECELRA® (afamitresgene autoleucel) with an Expanded Indication, Extending the First Approved Engineered T-Cell Therapy for a Solid Tumor to Children as Young as 12. PR Newswire. News release. June 22, 2026. Accessed June 23, 2026. https://www.prnewswire.com/news-releases/us-worldmeds-receives-full-us-fda-approval-of-tecelra-afamitresgene-autoleucel-with-an-expanded-indication-extending-the-first-approved-engineered-t-cell-therapy-for-a-solid-tumor-to-children-as-young-as-12-302806599.html

2. Adams CB, Bivacca L, Hatton R. Afamitresgene autoleucel: The First T-Cell Receptor Therapy on the Market. Pharmacy Times. December 16, 2025. Accessed June 23, 2026. https://www.pharmacytimes.com/view/afamitresgene-autoleucel-the-first-t-cell-receptor-therapy-on-the-market

3. Spearhead 1 Study in Subjects With Advanced Synovial Sarcoma or Myxoid/​Round Cell Liposarcoma. ClinicalTrials.gov identifier: NCT04044768. Updated February 6, 2026. Accessed June 23, 2026. https://clinicaltrials.gov/study/NCT04044768