ASH Clinical News ACN_5.6_Full_Issue_Digital | Page 24

Book Review Off to the Races The Breakthroughs of Immunotherapy In this edition, ASH Clinical News Associate Editor David Steensma, MD, reviews The Breakthrough, which traces the evolution of immunotherapy to treat – and potentially cure – cancer. Have you read any hematology-related books recently? Let us know what we should read and review by emailing us at [email protected]. F or decades, “cut, burn, and poison” were the only three conventional treatment approaches available to patients with cancer. Beginning with rituximab and imatinib in the 1990s, a fourth class of oncology therapy joined the triumvirate of surgery, radiotherapy, and chemotherapy: narrowly targeted “preci- sion” medications that were made pos- sible by a deeper understanding of cancer biology. We are now at the beginning of what looks to be a transformative period in cancer care, with the advent of a fifth method that could someday replace all the others: cancer immunotherapy. The Breakthrough, a new book by Charles Graeber, reviews the history of cancer immunotherapy, beginning with surgeon William Coley’s work with toxins in the 1890s, followed by immuno- therapy’s long fallow period, and ending with the ultimate triumph of the believ- ers in the form of regulatory approval of chimeric antigen receptor T-cell therapies and CTLA-4, PD-1, and PD-L1 immune checkpoint inhibitors. Immunotherapy is especially attrac- tive because, ultimately, cancer represents a failure of the immune system. Since we humans lack the 20 (!) copies of the TP53 gene that elephants use to aggressively police the genomes in their massive num- ber of cells, we regularly develop mutant cells that potentially could become cancer – twisted versions of “us.” Abnormal cells embedded in our tissues bearing DNA replication errors that have escaped DNA repair, or cells harboring genetic changes resulting from environmental injuries, represent clear and present dangers. Such abnormal cells are almost always safely recognized by immune cells for what they are and cleared. But, on rare occasions when the damaged cells are not elimi- nated, this oversight can allow a mutant cell to persist, expand, and become the taproot of a deadly neoplasm. Whenever I describe reduced-intensity allogeneic hematopoietic cell transplanta- tion to my patients with myelodysplastic syndromes or leukemia, I emphasize that the main goal of this species of transplant 22 ASH Clinical News is not to eliminate and replace all abnormal marrow cells with the conditioning regimen or the donor cells. Instead, the primary intention is to perform an immunologic “Control-Alt-Delete” and reboot the patient’s adaptive immunity in the hopes that a donor’s cells might recognize rogue malignant cells that have somehow hood- winked the patient’s own T cells into failing to sound an immunological alarm. As one of my patients who was cured by a second transplant from his sister after relapsing following a transplant from his brother quipped, “Well, that’s not surprising – she always was much more of a tattletale.” But an allogeneic transplant – rolling the dice for graft-versus-leukemia effect – is a drastic, risky way to re-engineer immunity. Better approaches are finally moving into the clinic. Cancer immunotherapy is certainly not a new concept. In the 1670s, before anyone knew the immune system existed, a few astute physicians noticed that patients with cancer who developed St. Anthony’s Fire (erysipelas) sometimes experienced sponta- neous tumor shrinkage. Two hundred years later, this phenomenon was known widely enough among the medical community that doctor-playwright Anton Chekhov mentioned it in an 1890 letter to a journalist friend in Saint Petersburg. In the early 19th century, a few reckless French physicians even used dirty bandages to dress the wounds of women with breast masses who had undergone mastectomy, in an attempt to infect those wounds and use “laudable pus” to eliminate residual tumors. Dr. Coley conducted the first serious experimental work in cancer immuno- therapy in New York in the 1890s. After a patient with advanced, inoperable cancer was cured by a serendipitous soft-tissue infection, Dr. Coley began to inject Bacillus prodigiosus and other bacterial strains into surgically unresectable cancerous masses and lymph nodes to try to reproduce the effect. Dr. Coley noted reduction in tumor size in many patients and even a few com- plete remissions. But the hit-and-miss (mostly miss) nature of Dr. Coley’s toxins, along with the advent of radium therapy shortly after Wilhelm Röntgen’s discov- ery of X-rays in 1895 and trials of aminopterin and nitrogen mustard chemotherapy in the 1940s, threat- ened to relegate immunotherapy to the “of historical interest only” file, alongside cup- ping and purging, ear candles, and aromatherapy for “wandering womb.” When Dr. Coley’s daughter Helen ap- proached the heads of major hospitals and research insti- tutes in New York, including C.P. “Dusty” Rhoads at the Rockefeller Institute and James Ewing at Memorial Hospital, she title: The Breakthrough: Immunotherapy and the Race to was dismissed. Cure Cancer To leaders like author: Charles Graeber length: 320 pages Rhoads and published: November 2018, Twelve/Hachette Book Group Ewing, immuno- therapy seemed Transformed Cell is appropriate, because far less appealing than other promis- Dr. Rosenberg and others’ 20th-century ing approaches of the day, like urethane work on interferon-alpha, interleukin-2, treatment or the decades-long search for and tumor-infiltrating lymphocytes is cancer-causing viruses. Yet, there were discussed in The Breakthrough. always a few true believers. Mr. Graeber is a nonfiction writer – a The Breakthrough is a quick and frequent contributor to Wired, The New compelling read, sprinkled with patient Yorker, and The New York Times. He is anecdotes. While reading, I was reminded perhaps most widely known for his 2013 of The Transformed Cell: Unlocking the best-seller, The Good Nurse: A True Story Mysteries of Cancer, by Steven Rosenberg, of Medicine, Madness, and Murder, about MD, PhD, and John Barry, which I New Jersey registered nurse and serial bought in medical school and found killer Charles Cullen (also known as “The inspiring. (With respect to “of historical Angel of Death”). Mr. Cullen was impli- interest only,” I bought Dr. Rosenberg’s cated in the deaths of hundreds of patients, book at an actual brick-and-mortar is currently serving multiple consecutive bookstore.) The comparison with The May 2019