Imdelltra for Small Cell Lung Cancer Addresses Key Unmet Needs

Imdelltra is a new type of treatment for patients with small cell lung cancer that isn't chemotherapy, experts emphasized.

Treatment for small cell lung cancer “really hasn’t changed for the last 30 years,” with many patients being treated with chemotherapy and immunotherapy, an expert told CURE®. Now, bispecific T-cell engager (BiTE) Imdelltra (tarlatamab) is a new option for patients with extensive-stage small cell lung cancer whose disease worsened after treatment with platinum-based chemotherapy.

Bispecific T-cell engagers bind two target proteins on different cells, such as healthy immune cells (T-cells) and cancer cells, to help destroy cancer cells, according to the National Cancer Institute.

“There really hasn't been any major breakthroughs in this [small cell lung cancer] area,” Dr. Sally Lau said during an interview with CURE®. “When the immunotherapies first came out — the checkpoint inhibitors — it moved the needle a little bit for these patients, but not to the same degree that we're seeing with Imdelltra. It is not like anything that we've ever seen before.”

Lau is a medical oncologist for thoracic cancers and a clinical trial investigator, including for the phase 2 DeLLphi-301 trial that led to the Food and Drug Administration’s accelerated approval of Imdelltra in May.

How Imdelltra Differs from Previous Treatments

Before the approval of Imdelltra, patients with small cell lung cancer were treated with a combination of chemotherapy and immunotherapy, specifically checkpoint inhibitors, Lau explained. When patients experienced cancer recurrence (the return of cancer), they would receive more chemotherapy.

“The armamentarium for small cell lung cancer in the past has been chemotherapy and more chemotherapy,” Lau said. “So, [Imdelltra] is new and something where we haven’t seen such great responses before, not just in a degree of [tumor] shrinkage, but also in the time that patients are living with small cell lung cancer.”

Even the addition of immunotherapy “works less well,” said Dr. Roy Herbst, deputy director, chief of medical oncology and director of the center for thoracic cancers at Yale Cancer Center, during an interview with CURE®.

“While we’ve seen some significant progress in the non-small cell [lung cancer] area, with targeted therapies and immunotherapies, in small cell [lung cancer], we haven't seen as much — the targeted therapies really don't apply,” Herbst said. “We're seeing patients with responses [to] this drug. Serious shrinking of their tumors is a huge benefit. This accelerated approval of [Imdelltra] really is something that is great for patients to have as something available to them for their treatment.”

In the DeLLphi-301 trial published in The New England Journal of Medicine in 2023, patients who received 10 milligrams of Imdelltra had an objective response rate (percentage of patients whose tumors shrank or disappeared) of 40%.

“I think that a 40% response rate in patients who are refractory to chemotherapy or chemoimmunotherapy in small cell lung cancer is huge,” Herbst emphasized. “This is an area where we're using [chemotherapy] with less than 10% response rate [and] [Hycamtin (topotecan)] with less response rate and a ton of toxicity. So, I think that [Imdelltra] is a very attractive approach.”

Unmet Needs Addressed by Imdelltra

With this new type of drug in the small cell lung cancer space, Lau explained that two main unmet needs have been addressed.

“One is within small cell lung cancer — obviously, we didn’t have any [other] treatment options for patients. It would be more chemotherapy, and in this case, chemotherapy that doesn’t work that great,” she said. “The second thing that I think Imdelltra really addresses as an unmet need in that it is a first-in-class therapy for solid tumors.”

A first-in-class therapy is defined as a treatment that has a unique way of treating patients and hasn’t been previously used before, according to Lau.

“This highlights that these BiTE therapies can be done for solid tumors and that they do work for solid tumors,” she said. “I think being first-in-class, it really does open up a lot of treatment options for other tumor subtypes as well.”

Unmet Needs Still Persist in Small Cell Lung Cancer

Although Imdelltra addresses a large unmet need in small cell lung cancer, there are still areas to be improved upon.

Within small cell lung cancer, Lau emphasized, there still are not enough novel therapies. However, she noted that more of these novel treatments are “definitely coming with many other agents that are in development.”

Similarly, Herbst explained that more approaches are needed to improve responses and durability — delaying disease worsening and tolerating treatment.

“We still don’t know that [Imdelltra] will make this a curable disease,” Herbst said. “We need to have immunotherapy that both has an early effect and causes a response, but we [also] need durability. We've yet to prove that this has durability, but there are some hints of that. We’ll have to wait and see, but we’re hopeful.”

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