Biotechnology sector-related exchange traded funds were among the few areas of the markets that shook off the tariffs-talk volatility and was still in the green Tuesday as Sarepta Therapeutics (NasdaqGS: SRPT) surged on positive preliminary results from its experimental treatment.

The BioShares Biotechnology Products Fund (NasdaqGM: BBP), which follows U.S.-listed biotech companies with a primary product offering or product candidate that has landed FDA approval, and SPDR S&P Biotech ETF (NYSEArca: XBI), which takes an equal-weight approach to the biotech space, were among the better performing ETFs Tuesday, rising 2.2% and 1.3%, respectively.

Meanwhile, the iShares Nasdaq Biotechnology ETF (NASDAQGM: IBB), the largest biotech exchange traded fund by assets, was 1.3% higher Tuesday.

These biotech ETFs with a greater tilt toward smaller companies strengthened after SRPT shares jumped over 50% Tuesday but eventually settled near 33.3% later in the day. SRPT makes up 2.5% of BBP’s underlying portfolio and 1.4% of XBI’s holdings.

Sarepta Therapeutics shares jumped after the company shared preliminary data for its experimental treatment for patients with Duchenne muscular dystrophy, a rare genetic disease that causes muscle wasting and can be fatal before patients turn 30, CNBC reports. Sarepta revealed results from three children who received the gene therapy in a phase 1/2a clinical trial.

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The results “meaningfully beat even the highest of expectations,” J.P. Morgan analyst Anupam Rama wrote in a note to clients.

Patients showed an average reduction of more than 87 percent in creatine kinase levels on day 60 – creatine kinase is an enzyme found within muscle cells that flow into the bloodstream due to muscle damage. Elevated creatine kinase is an indicator for Duchenne muscular dystrophy.

“I have been waiting my entire 49-year career to find a therapy that dramatically reduces CK levels and creates significant levels of dystrophin,” Dr. Jerry Mendell of Nationwide Children’s Hospital said in a statement. “Although the data are early and preliminary, these results, if they persist and are confirmed in additional patients, will represent an unprecedented advancement in the treatment of DMD.”

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