Inhaled Gene Therapy: A New Approach to Lung Cancer Treatment

Written By Aaron Wang | USA

Introduction:

What if lung cancer could be treated by breathing in a virus engineered to heal rather than harm? That is the revolutionary idea behind Inhaled KB707, a novel gene therapy pioneered by Krystal Biotech, a commercial-stage biotechnology company headquartered in Pittsburgh, PA. Inhaled KB707 uses herpes simplex virus (HSV-1) to deliver cytokines (small proteins that regulate immune response) to tumor cells in cancer patients [1]. Normally, viruses attack healthy cells by injecting their own genetic material and hijacking the host to reproduce and spread the infection. The HSV-1 vector in KB707, however, is genetically engineered to be replication-defective, meaning that the virus is harmless—i.e., lacks the ability to multiply and infect neighboring cells.

KB707 targets Non-Small Cell Lung Carcinoma (NSCLC), the most common type of lung cancer [2]. Through inhalation, the viral vector reaches the cancerous cells in the lungs and inserts genes that encode for interleukin-2 (IL-2) and interleukin-12 (IL-12), proteins that stimulate the production of white blood cells [1]. By doing so, KB707 boosts the body’s immune response and enhances its capacity to fight off tumor cells.

Potential Benefits:

Traditionally, IL-2 and IL-12 proteins are administered intravenously or orally, but these modes of delivery can cause serious side effects such as hypotension, arrhythmias, fever, nausea, and vomiting [3]. By contrast, KB707 works through inhalation. By confining the dose to the lungs, many of the systemic side effects are eliminated [1].

According to the World Health Organization, lung cancer is the most frequently diagnosed and most lethal form of cancer globally, contributing to 18% of cancer-related deaths. Non-Small Cell Lung Carcinoma accounts for approximately 85% of all lung cancer cases [4]. The main risk factors for NSCLC include smoking, exposure to toxic gases and heavy metals, and environmental pollution [5]. Because of the high prevalence and mortality of lung cancer, experts believe that this newly developed gene therapy could be a game-changer.

KB707’s delivery system is non-invasive. Many patients have stage IV lung cancer by the time they’re diagnosed, and due to the advanced stage of the disease, surgery is not always the recommended course of treatment. But there are further advantages to this treatment option. Intravenous and oral delivery of cancer-treating medications is often harmful to the liver [6]. In fact, the liver is responsible for metabolizing (breaking down) drugs that circulate through the bloodstream. When enzymes accumulate in the liver to process medications, they can cause liver problems. IV and oral delivery techniques are also less effective than inhalation. Lungs contain fewer enzymes, so more of the drug is available to tissues and cells. This allows for lower dosage, making toxicity due to a buildup of the medication in the lungs less likely [7].

Potential Risks:

Still, the benefits of the lower dosages are partially offset by the higher bioavailability of the drug, which can result in the accumulation of the medication in the lungs, causing pulmonary toxicity. The issue is particularly relevant for lung cancer patients, many of whom are former smokers and exhibit weakened lung immunity [7]. Additionally, the cilia underneath the mucus layer that lines the lungs work to trap and remove inhaled particles, posing challenges to the effective delivery of drugs to the lungs. Because smokers and individuals with pre-existing conditions have thickened mucus layers, mucociliary clearance of the drug in lung cancer patients tends to be more aggressive [7].

Looking Ahead:

KB707 holds great promise for the future of lung cancer treatment because it is highly effective, targeted, and non-invasive. Surgery, on the other hand, is very invasive and expensive. Surgical operations usually require a long recovery period and present the risk of infection. Chemotherapy is another common treatment option. However, chemotherapy doesn’t just kill rapidly dividing cancerous cells; it harms healthy cells and weakens the human body’s defense against infections, too.

In early clinical trials, inhaled KB707 has shown no severe side effects. 36% of patients with pre-treated Non-Small Cell Lung Carcinoma ended up with improved conditions, and several had durable responses—that is, their tumors shrank or disappeared over an extended period of time [8].

A 2023 study revealed that conventional late-stage NSCLC treatments cost $17,300 a month [9]. For one year of chemotherapy, the total cost to a patient can reach $50,000 [10]. The hope is that, once KB707 becomes commercialized and widely available to the public, prices will drop and insurance companies will cover the costs. There is a long way to go to confirm the safety and efficacy of KB707 across multiple conditions and clinical trials. Still, there are reasons to be optimistic. Recently, the U.S. Food and Drug Administration gave KB707 trials a special designation of Regenerative Medicine Advanced Therapy, which is expected to expedite the development and review process of inhaled lung cancer treatments [11].

References:

  1. Shepherd, Dale. “Breathing New Life Into Cancer Treatments: Inhaled KB707.” Cancer Advances, Cleveland Clinic. Aug 28, 2025. https://my.clevelandclinic.org/podcasts/cancer-advances/breathing-new-life-into-cancer-treatment-inhaled-kb707. Accessed Feb 26, 2026.

  2. Cleveland Clinic. “Non-Small Cell Lung Cancer.” https://my.clevelandclinic.org/health/diseases/6203-non-small-cell-lung-cancer. Accessed Feb 27, 2026.

  3. Barber, Fedricker D. “Adverse Events of Oncologic Immunotherapy and Their Management.” Asia-Pacific Journal of Oncology Nursing, vol. 6, no. 3, Jul. 2019, p. 212-226. https://doi.org/10.4103/apjon.apjon_6_19.

  4. World Health Organization (WHO). "Global cancer burden growing, amidst mounting need for services." Feb 1, 2024.  https://www.who.int/news/item/01-02-2024-global-cancer-burden-growing--amidst-mounting-need-for-services. Accessed Feb 18, 2026.

  5. Centers for Disease Control and Prevention (CDC). “Lung Cancer Risk Factors.” Feb 13, 2025. https://www.cdc.gov/lung-cancer/risk-factors/index.html.

  6. Okonak, Katherine. “Liver Problems Caused by Cancer Treatment.” OncoLink. Jun 3, 2025. https://www.oncolink.org/support/side-effects/other-side-effects/liver-problems-caused-by-cancer-treatment.

  7. Gupta, Chetna. “Inhalable Formulations to Treat Non-Small Cell Lung Cancer (NSCLC): Recent Therapies and Developments.” Pharmaceutics. Dec 31, 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9861595/. Accessed Feb 19, 2026.

  8. Krystal Biotech. “Krystal Biotech Announces Second Quarter 2025 Financial and Operating Results.” Press release. Aug 4, 2025. https://ir.krystalbio.com/news-releases/news-release-details/krystal-biotech-announces-second-quarter-2025-financial-and.

  9. Gillette, Hope. “Financial Support and Information on Paying for NSCLC Treatment.” Living with Lung Cancer. Healthline. Feb 20, 2025. https://www.healthline.com/health/nsclc/paying-for-nsclc-treatment#real-cost. Accessed Feb 26, 2026.

  10. Ernst, Rachel. “How Much Does Lung Cancer Treatment Cost?” Lung Cancer Center. Apr 1, 2024. https://www.lungcancercenter.com/news/lung-cancer-treatment-cost/. Accessed Mar 1, 2026.

  11. Serani, Sabrina. “FDA Grants RMAT Designation to Inhalable Gene Therapy for Advanced Lung Tumors.” Targeted Oncology. Feb 11, 2026. https://www.targetedonc.com/view/fda-grants-rmat-designation-to-inhalable-gene-therapy-for-advanced-lung-tumors. Accessed Mar 2, 2026.

Aaron Wang | USA
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