Ac­celeron dumps dalantercept after kidney cancer trial fail

Acceleron dropped dalantercept after it failed to improve PFS in kidney cancer patients

Acceleron Pharma has jettisoned dalantercept after the inhibitor of ALK1 signaling failed to move the needle in a phase 2 kidney cancer trial. The setback intensifies the focus on Acceleron’s lead, Celgene-partnered rare blood disease drug luspatercept.

Management hoped dalantercept would improve PFS by stopping the formation of the blood vessels tumors need to source the resources that enable them to grow and spread. VEGF inhibitors, such as Novartis’ Votrient and Pfizer’s Sutent, already provide kidney cancer patients with such a brake on angiogenesis. But, with dalantercept having a different mechanism of action than these drugs, Acceleron spied an opportunity to carve out a niche for the drug.

The phase 2 data slammed the door on that opportunity.

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Investigators enrolled 131 patients with advanced renal cell carcinoma and randomized them to receive one of two regimens. Half of the participants received dalantercept plus Pfizer’s tyrosine kinase inhibitor Inlyta. The other half received Inlyta plus a placebo. Acceleron monitored the effect of the treatments on progression-free survival (PFS).

Dalantercept fell short against its primary PFS endpoint. The experimental cocktail chalked up a median PFS of 6.8 months, versus 5.6 months for the Inlyta plus placebo regimen. That difference fell short of statistical significance.

The trial delivered similarly subpar data against other endpoints. Dalantercept failed to cut the rate of disease progression or death. In patients who had received two or more prior systemic cancer therapies—a key subpopulation—the dalantercept and placebo arms achieved median PFS of 8.1 months and 7.0 months, respectively. The placebo arm outperformed dalantercept in terms of the objective response rate (ORR), racking up a figure of 25% as compared to 19% for the experimental drug.

Publication of the data follows the release of underwhelming results from a trial of patients with platinum-refractory, recurrent or metastatic squamous cell carcinoma of the head and neck. That earlier trial recorded an ORR of 5%. ORR was the primary endpoint of the trial.

With neither trial finding much evidence of efficacy, Acceleron has dumped dalantercept. The data and subsequent decision to drop the drug had little effect on the share price of Acceleron, which slipped 5% in after-hours trading. The muted reaction of traders is testament to the relative unimportance of dalantercept to the fate of the company.

Acceleron’s key asset is luspatercept. The TGF-beta inhibitor is working its way through phase 3 trials in myelodysplastic syndromes and beta-thalassemia.