UPDATE: Nkarta touts a double dose of data for natural killer cell therapies

Two is always better than one, especially when it comes to data. With that in mind, Nkarta is revealing a peek at interim results for its two leading engineered natural killer (NK) cell programs to treat cancer.

“It’s one thing when you have interim data on one compound that’s promising and impressive,” Paul Hastings, Nkarta’s president and CEO, told Fierce Biotech. “It’s even better when we can do it with two.”

The San Francisco-based biopharmaceutical’s preliminary Phase 1 dose data assesses NKX101 and NKX019 — two chimeric antigen receptor NK cell therapy candidates — in small, independent groups. 

The impact of NKX101 was evaluated in patients with relapsed/refractory acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), for which there is currently no standard of care available. A complete response (60%) with hematologic recovery was achieved in three of five patients who had heavily pre-treated AML and received the higher dose level in a three-dose regimen, with two of the three responses reaching minimal residual disease negative.

The second trial assessed NKX019 among six patients with relapsed/refractory B cell malignancies. Three of six patients treated at the higher dose level in a three-dose regimen showed a complete response (50%), including one patient with aggressive diffuse large B cell lymphoma and one with mantle cell lymphoma.

After the preliminary data was published Monday morning, Nkarta’s stock shot up more than 90% in pre-market trading. As of 2:55 p.m. ET, the stock was up 127% to $17.62, gaining more than $9 in value compared to a prior close of $7.77.

“Nobody has produced data like this,” Hastings declared, noting that the diseases have a high unmet medical need and are of the utmost priority for Nkarta.

Both trials have a clean safety profile, Hastings said, adding that no dose limiting toxicity was observed and no common adverse events typically associated with CAR-Ts were observed.

After a major $114 million series B round in 2019, Nkarta launched with a $252 million IPO in 2020, one of the biggest life science public debuts that year.

Then, in May of last year, the company partnered with gene-editing giant CRISPR Therapeutics, though the technology hasn’t been applied to NKX101 and NKX019. Under the deal, of which financials were not disclosed, CRISPR and Nkarta will pursue CRISPR/Cas9 gene-edited cell therapies for cancer. This gene editing collab is another of Nkarta’s top priorities, following NKX101 and NKX019, according to Hastings.

Nkarta will now move the two NK candidates to the next group—five or six patients for each therapy again—with higher doses, Hastings said. The company anticipates the clinical results to be available by the end of the year.

Hastings expects to develop multiple other targets to put on the NK platform, though the company hasn’t publicly disclosed any others yet. The CEO said Nkarta will continue developing a balance of both novelty and already established targets to ensure a risk diversified pipeline.