Blood Cancer Player Arcellx's Lead Product Exceeds Expectations, Analysts Say

Friday, Arcellx Inc ACLX announced new data from its Phase 1 expansion study of CART-ddBCMA, now known as anitocabtagene autoleucel (anito-cel) for relapsed and/or refractory multiple myeloma. 

The interim anito-cel Phase 1 clinical results (October 15, 2023 cutoff date) demonstrate deep and durable responses. Of the 38 evaluable patients with a median follow-up of 26.5 months:

• A 100% overall response rate (ORR) was achieved in all patients per IMWG criteria.
• 29/38 evaluable patients achieved a complete response (CR) or a stringent complete response (sCR) (>CR rate, 76%)
• 35/38 patients achieved a very good partial response or higher (>VGPR rate, 92%).

Median duration of response, progression-free survival, and overall survival rate not reached with median follow-up after CART-ddBCMA (anito-cel) infusion of 26.5 months.

William Blair views median progression-free survival (mPFS) not being achieved at 26.5 months as exceeding expectations heading into the data readout.

Given the overall efficacy/safety profile of anito-cel to date, the analyst is inclined to say it is a potentially best-in-class program and notes the consistent PFS rates across subgroups and tolerable safety profile suggest that anito-cel could be a differentiated therapy for MM, particularly for patients with poor prognostic factors.

Needham writes that Anito-cel exceeds expectations, with an estimated mPFS of 28 months at 26.5 months of follow-up. 

24-month PFS was 56%, in line with the top scenario, and comparable to what Johnson & Johnson JNJ/Legend Biotech LEGN Carvykti achieved in CARTITUDE-1 (~59% PFS at 24 months and 27-month mPFS). 

The analyst raised the price target to $65 from $60 and reiterated the Buy rating after raising expected market potential in 3rd line multiple myeloma to ~$3.5 billion by 2033.

Price Action: ACLX shares are down 8.73% at $51.31 on the last check Monday.