What happened

CRISPR Therapeutics AG (CRSP 0.99%), a gene-editing clinical-stage biotech company, saw its shares fall 19.9% in November, according to data from S&P Global Intelligence. The stock ended September at $65.35 a share.

It opened October at $66.02 and then fell steadily throughout the month, dropping to a monthly low of $48.49 on Oct. 24. The stock concluded the month at $52.34 and is down more than 33% so far this year, with a 52-week low of $42.51 and a 52-week high of $95.

So what

Several factors helped drive down the stock. It had been a favorite of Cathie Wood's Ark Innovation ETF, but the fund has been selling the stock lately, and on Oct. 20, it sold 22,681 shares of CRISPR.

Another concern, not just for CRISPR Therapeutics, but for investors in other gene-editing companies, was the death last month of the lone volunteer in a study for a gene-editing therapy. The patient, 27-year-old Terry Horgan, had Duchenne muscular dystrophy and was the brother of Rich Horgan, the founder of Cure Rare disease, a Connecticut-based nonprofit.

CRISPR also announced on Oct. 27 that its chief operating officer, Lawrence Klein, was stepping down from the company and that may be seen as a negative sign by some investors.

On top of all that, CRISPR CEO Samarth Kulkarni sold 25,000 shares of the company on Oct. 28.

Now what

The key for CRISPR will be when and if exa-cel, a severe sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TBT) therapy it is developing with Vertex Pharmaceuticals, is approved by the Food and Drug Administration (FDA). The companies said that exa-cel's biologics license applications (BLAs) will be submitted to the FDA for a rolling review this month, with the completion of the BLA submission package scheduled for the first quarter of 2023.

Exa-cel has huge potential for the companies as a cure for the two genetic blood disorders. In June, the company said, in Climb clinical studies of exa-cel, of the 44 TDT patients in the trial, 42 of them were transfusion free in follow-up reports after the therapy. Of the 31 patients with severe SCD in the trial, all 31 patients in the trial were free of painful recurrent vaso-occlusive crises typical of those with SCD in a follow-up.

Financially, though CRISPR has a strong cash position, as a clinical-stage biotech, it needs an approved therapy to help it turn the corner. In the company's third-quarter report, it reported it had $1.9 billion in cash but revenue of only $100,000, compared to revenue of $300,000 in the same period last year. Its net loss in the quarter was $174.5, compared to the $127.2 million it lost in the third quarter of 2021.