What happened

Shares of NextCure (NASDAQ:NXTC) fell as much as 55.3% today after the company presented updated data for NC318 over the weekend. The expanded results aren't as rosy as the preliminary data reported earlier this month that caused the small-cap stock to erupt for a daily gain of more than 200%.

But great results from a low number of patients mean relatively little until they're replicated in larger populations. That said, it's a little difficult to draw too many conclusions one way or the other for the ongoing phase 1/2 trial of NC318. It was evaluated in many tumor types, with many doses, and with many unique genetic profiles of the individuals involved. NextCure will need results with fewer variables (such as settling on a dose or two) and from a much larger patient population before investors know if the company's novel approach to discovering immunotherapy drug candidates can live up to the hype.

As of 11:23 a.m. EST, the stock had settled to a 51.6% loss.

A pink arrow crashing through the x-axis of a chart.

Image source: Getty Images.

So what

In the preliminary data reported in the beginning of November, 5 of the first 7 non-small cell lung cancer (NSCLC) patients treated with NC318 in the phase 1/2 trial achieved a response or stopped their cancers from progressing as of the cutoff date. That included one complete response (read: no signs of cancer), one partial response (read: tumor shrinkage), and three patients with stable disease. That translated to a disease control rate (DCR) of 71%.

In the updated data reported over the weekend at the Annual Meeting of the Society for Immunotherapy of Cancer (SITC), NextCure presented results from 10 patients with NSCLC who were evaluable at the new cutoff date. No new responses or signs of stable disease were reported, and four patients dropped out of the study. Three more have yet to reach the eight-week check-in, which means they were not evaluable and were not included in the most recent data.

The results are also a little messy. The patient who achieved a complete response took an 8 mg dose of NC318 every two weeks, while the patient who achieved a partial response took 400 mg every two weeks. Three patients with stable disease are taking an 80 mg dose every two weeks, and the other is on the 400 mg dose.

NextCure also evaluated its lead drug candidate beyond NSCLC, studying 15 unique tumor types in all as part of the study. There were 14 patients with stable disease in all, although only 15 remain in the phase 1 trial.

Now what

Despite today's drop, shares of NextCure have gained 56% in the last month. But today's news is just the latest reminder that investors shouldn't get too carried away when it comes to clinical results from a very small number of patients. Oftentimes, the numbers simply don't hold up. That said, the ongoing phase 1/2 trial will progress to a larger phase 2 study, which will provide more valuable data for investors to pore over. It should be completed by the end of 2020 or early 2021.