This week in CGT: Beacon, Prime Medicine and Kyverna advance clinical programmes

Beacon Therapeutics reports pivotal success for XLRP gene therapy

Beacon Therapeutics has reported positive topline results from its Phase 2/3 VISTA study of laru-zova in X-linked retinitis pigmentosa (XLRP), setting the stage for a potential regulatory submission.

The study evaluated two doses of laru-zova in 85 male patients aged 12 to 48 with XLRP. At 12 months, 24.1% of patients in the low-dose group and 31% in the high-dose group achieved the study’s primary endpoint. Beacon described the result as the first time a pivotal trial of an XLRP treatment has met its primary endpoint. The company plans to begin a rolling BLA submission to the FDA before the end of 2026, while also pursuing potential regulatory approvals in Europe and the UK.

The result is particularly notable given previous setbacks in the XLRP gene therapy field. Beacon's approach delivers a full-length copy of the RPGR gene using an AAV vector, with the company highlighting codon optimisation designed to improve the stability of the therapeutic gene.

Read more via Biopharma Dive

Prime Medicine receives FDA clearance for PM647

Prime Medicine has received FDA clearance of its IND application for PM647, an investigational in vivo Prime Editing therapy for alpha-1 antitrypsin deficiency (AATD).

The clearance allows Prime Medicine to begin clinical development of PM647 in the US. The company plans a global Phase 1/2, first-in-human study evaluating the safety, tolerability and preliminary efficacy of ascending doses of a one-time intravenous infusion. Initial enrolment will focus on adults with lung-only manifestations of AATD, before expanding to patients with significant liver disease following demonstration of tolerability.

The programme also provides another test of Prime Medicine's broader platform strategy. PM647 follows recent regulatory clearances for PM577a, with the company highlighting the use of a common liver-targeting LNP system across multiple programmes. Initial clinical data from PM647 are expected in 2027.

For the broader in vivo editing field, the progression of multiple programmes towards human studies will provide an increasingly important test of whether platform-based approaches can translate from preclinical promise into repeatable clinical development.

Read more via Globe News Wire

Kyverna reports sustained CAR-T responses in autoimmune disease

Kyverna Therapeutics has released one-year data for mivocabtagene autoleucel (miv-cel), adding further evidence to its case for CAR-T in autoimmune disease.

In the KYSA-8 trial in stiff person syndrome (SPS), 26 patients treated with a single dose of miv-cel showed a median 49% improvement from baseline on the timed 25-foot walk test at 12 months, compared with a 46% improvement at 16 weeks. Of the patients who had achieved a clinically meaningful response at the primary analysis, 95% maintained that benefit at one year.

The data also showed sustained improvements in mobility. Eight of the 12 patients who had required a walking aid before treatment no longer required assistance at one year, while 92% of patients remained free of chronic immunotherapy.

Kyverna is now on track to complete its rolling BLA submission for miv-cel in SPS in the fourth quarter of 2026, with the company seeking priority review. If approved, miv-cel would become the first CAR-T therapy approved for an autoimmune disease. The company also reported longer-term data from the Phase 2 portion of its KYSA-6 study in generalized myasthenia gravis. All five patients with at least one year of follow-up maintained clinically meaningful improvements, supporting the company's broader strategy of applying a single CAR-T platform across autoimmune and neuroimmunological indications.

Read more via Biospace