By Chelsea Karnash

PHILADELPHIA (CBS) – A Philadelphia chef at one of the city’s top restaurants has stepped down due to his fight with a deadly illness.

Rex 1516’s executive chef Regis Jansen, who suffers from cystic fibrosis, is officially resigning due to medical reasons.

In a press release on Tuesday, Jansen says, “I am incredibly grateful for the opportunity and support owners Jill Weber and Evan Malone have given me. Being part of the REX 1516 launch has been a true highlight in my culinary career. At this time, I am not able to give the restaurant 100% and I don’t operate in any other way. It is only fair for me, my family and our customers for me to take this time to focus on my health.”

It’s sad news for the Philadelphia restaurant community, but the South Street eatery is doing what it can to help Jansen out. Throughout January, Rex 1516 will be offering a special drink, the Snappy Pamplemousse, made from Art in the Age’s Snap, Combier Pamplemousse Rose, St. Elizabeth Allspice Dram, fresh orange juice and angostura bitters. One-hundred-percent of the proceeds from the creative cocktail will be donated to MANNA, the nonprofit that has been assisting Chef Jansen during his medical struggles.

Meanwhile, the restaurant is hoping for a smooth transition over to the new chef, Jansen’s close friend Justin Swain, as well as a swift recovery for Jansen.