It’s a tale of two U.S. Food and Drug Administration decisions – one negative and the other positive – involving two different local immunotherapy companies announced on the same day.

On May 5, Culver City-based ImmunityBio Inc. announced that on Friday, May 2, it had received a rejection letter from the FDA for its first expanded application for its Anktiva drug beyond the agency’s approval last year to treat a subset of patients with bladder cancer. The new application is to treat a slightly different subset of patients with a form of bladder cancer.

The company publicly called for a meeting with the agency to address the FDA’s rejection letter. Meanwhile, its stock plunged 25% over the next three trading sessions.

Just hours later came more positive FDA news from Thousand Oaks-based Atara Biotherapeutics Inc. The company announced that the FDA had notified it that the agency is lifting its hold on clinical trials for the company’s drug Ebvallo to treat blood cancers. The FDA notice also granted a date for the company to meet with agency officials to go over the path to resubmitting Ebvallo for consideration. Atara stock jumped 6% on the news.

ImmunityBio shocked by FDA letter

ImmunityBio scored a major victory one year ago when the FDA approved its Anktiva immunotherapy drug to treat a subset of patients with bladder cancer. It was the first FDA approval ever for the 10-year-old company, enabling it to market the drug and pocket its first significant revenue from drug sales.

In April, ImmunityBio held an investor day conference outlining its plans to expand the treatment uses and patient pools for Anktiva over the next few years. The expanded uses include a variation of the drug to boost counts of white blood cells known as lymphocytes in patients with a wide range of cancers; that variation has the potential to become a blockbuster drug, according to Chief Executive Richard Adcock.

But all these grand plans were contingent on one thing: a continuous string of approvals from the FDA.

But the FDA rejected the first expanded use application for Anktiva to come out of the gate, one that would expand the eligible pool of bladder cancer patients four-fold. ImmunityBio received the rejection letter – known in agency parlance as a “refusal to file” (RTF) letter – on May 2. According to the FDA’s website, such a letter “notifies a drug company that (the) FDA will not review a marketing application because of significant deficiencies that cannot promptly be resolved, making the application substantially incomplete.”

An agency spokeswoman said the FDA does not disclose the contents of RTF letters and said it was up to the company whether to divulge any of the contents.

Urging the FDA to meet

In announcing the receipt of the letter, ImmunityBio did not disclose any of the reasons for the FDA’s rejection. Instead, the announcement urged the FDA to accept a meeting to go over the issues. The company said the rejection letter was inconsistent with both the initial Anktiva drug approval one year ago and with recommendations shared by FDA officials in a meeting with ImmunityBio executives in January.

“The Agency must explain the confounding inconsistency of approving ANKTIVA+BCG for patients with Papillary with CIS disease, while refusing to file the sBLA for patients with Papillary without CIS disease – even though both groups were part of the same trial,” Patrick Soon-Shiong, ImmunityBio’s billionaire founder and executive chairman said the company’s announcement. “On behalf of patients facing a potential loss of a vital organ (the bladder) and high risk of progression of disease, I urge the Agency to reconsider and act now,” he added.

As of press time, the company had no updates on the matter.

Better FDA news for Atara

In January, Atara Biotherapeutics also received a rejection letter from the FDA for its drug Ebvallo to treat blood cancers, though the letter was much narrower in scope. The “complete response” letter referenced concerns with the third-party manufacturer’s compliance with standards. The letter did not reference any problems with the safety or efficacy of the drug itself.

Complete response letters are fairly common and often involve having the third-party manufacturer institute additional protocols to ensure consistent quality and safety in mass-producing the drug. ImmunityBio received a complete response letter in late 2023 that resulted in a six-month delay in the FDA’s approval for its Anktiva drug.

This announcement sent Atara shares down more than 50% to $6.05 on Jan. 21.

A few days later, Atara revealed that the FDA had placed a hold on all clinical trials involving the Ebvallo drug.

The company said in its announcement of the complete response letter that it was working with the FDA to resolve the issues with the unnamed third-party manufacturer.

On May 5, Atara announced some success in this regard: the FDA agreed to lift the hold on clinical trials and that a date had been set for a meeting with the agency to address the issues raised in the complete response letter. According to the company, that meeting will also consider the path forward for resubmission of the application to market Ebvallo.

“We are pleased that the FDA has granted our request for a Type A meeting and hope to gain clarity on the timing for resubmitting the tab-cel BLA for review by the FDA,” Cokey Nguyen, Atara’s chief executive, said in the company’s announcement.