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The spirited decades-old journey of interferon alfa.
The discovery and molecular understanding of the cellular mechanisms and clinical use of interferons (IFNs) have been a major advance in medicine over the past 50 years. This family of proteins stimulates intracellular and intercellular networks that regulate resistance to viral infections, enhance innate and acquired immune responses, and modulate normal and tumor cell survival and death. After their discovery in 1957,1 it was soon appreciated that IFNs were extremely important to human health and that the IFN system had potential as a therapy for viral infections and cancers.
Domenico Criscuolo, MD
However, advances in molecular biology up to the 1970s were required before the promise could be realized. The 1980s saw their introduction into the clinic among the first pharmaceutical products of the newborn biotech industry, and, importantly, as a demonstration of the effectiveness of IFNs not only for viral diseases but also for cancers. The 1980s were marked by an expansion in their clinical applications with regulatory approvals worldwide and a further understanding of molecular events influencing biological actions.
In this article, I will try to summarize the first steps of interferon clinical studies, the first failures, and finally the identification of its correct place in therapeutics.
The first recombinant protein, produced in large amounts by the newborn biotech industry, was human insulin. However, the clinical use of this product had no surprises, and it simply was made available to patients to replace insulin of animal origins.
The real challenge was indeed the identification of suitable medical use of interferon alfa, and its best way of administration to patients. Since its discovery,1 interferon alfa raised a high degree of scientific interest, possibly further stimulated by the difficulty of obtaining the product for clinical trials. Indeed, until the late 1970s the only source of interferon alfa was the limited production made available to selected investigators by the Finnish Red Cross. Therefore, when in the early 1980s Genentech in the United States and Hoffmann-La Roche in Europe, as well as Schering-Plough and Wellcome, made available to the scientific community large amounts of recombinant interferon alfa, an explosion of enthusiasm and a subsequent explosion of clinical studies was recorded.
The first volunteer studies stressed the good safety and tolerability profile of interferon alfa: Doses up to 100 million units (MU) were injected and apparently well tolerated, apart from the so-called flu-like syndrome. This adverse reaction would accompany all human studies with the product, and is characterized by fever, chills, and muscular and joint pain.
Despite the fact that interferon alfa has a strong antiviral activity, the first studies were planned addressing its use in oncology, as the medical need, and the hopes for a successful treatment, were more pronounced. Proof of concept studies in malignant melanoma, gastric cancer, pancreatic cancer, and renal cancer were activated almost simultaneously, with the 100 MU dose derived from Phase I studies. Unfortunately, all studies were failures: Some activity was apparent but quite limited and certainly not at the level of expectations.
It happens frequently in the development of a new drug: Interferon alfa was the first in a new class but its promises were unmet, and the product entered into a negative loop.
All of a sudden in 1984, Quesada et al reported in the New England Journal of Medicine impressive results obtained with low doses of interferon alfa in a few patients affected by hairy cell leukemia, a rare but well-described form of chronic leukemia.2 The identification of a niche indication where interferon alfa had a remarkable clinical effect reverted immediately the negative trend. Interferon alfa became again a new and interesting scientific tool, and hematologists were testing its use in several hematological malignancies—mainly chronic leukemias.
In those days, June 1984, I had just joined Roche Milano as head of international clinical research. With my educational background as a hematologist, I was very impressed by these preliminary findings and approached the Italian Cooperative Group on Chronic Myelogenous Leukemia (CML), headed by Professors Sante Tura and Michele Baccarani at the Bologna University.
I offered to them the unique opportunity of being the first investigator group to perform a large scale study in CML with interferon alfa. They immediately accepted the opportunity. We quickly developed a clinical protocol, got the approval from Bologna University's Ethical Committee, and in just two to three months time, in early September 1985, the first patients were already in the study.
The enthusiasm of the investigators, having the opportunity to treat their patients with interferon alfa, was unforgettable. Their motivation became more evident as the first clinical results became available, indicating a significant clinical benefit and a clear superiority versus the available chemotherapy based on hydroxyurea.
I still remember the great days of that study, the meetings we had in Bologna, when the 60 or so Italian investigators (all existing Italian hematology clinics at that time) met every year to comment on the impressive results, and finally the great satisfaction when our results were accepted as an oral presentation at ASCO and subsequently as a full paper in the New England Journal of Medicine.3
What types of lessons did we learn from that experience? Quite a lot, let me honestly say. And, if we take into consideration that I am referring to 1985, well before GCP and SOPs, let me underline that the entire process was based on a high quality approach.
First, we developed a scientifically sound protocol, including a central randomization in Bologna. Treatments were assigned, making sure to have a balanced distribution within each center. Laboratory confirmation of the diagnosis was centralized in Bologna, which also took responsibility for assessing caryotipic conversion of the Philadelphia chromosome in patients achieving a clinical remission.
In addition, a centralized data management system ensured complete control of the study progress and the analysis of clinical and lab results on an ongoing basis.
Finally, we took very seriously the safety aspect of the study. The interferon alfa dose was selected at the lower end of the range of effective doses, and this decision was certainly instrumental in ensuring the compliance of patients to the prescribed regimen.
This study formed the basis for a regulatory approval obtained both at EMEA and at FDA. Federal inspectors from the United States visited eight Italian sites and confirmed the quality of the study.
Interferon alfa therapy became the gold standard of treatment in patients with CML for more than a decade. It has been exceeded only recently by the even greater effectiveness of the targeted inhibitor of the activated BCR–ABL kinase, such as imatinib, and other newer tyrosine kinase inhibitors.4
Another story I would like to refer to is related to the clinical development of interferon alfa in malignant melanoma. Preliminary findings suggested a potential use in this indication, but clinical evidence was never clear cut.
In the late 1980s a group of Italian experts in melanoma, headed by Professor Natale Cascinelli of the National Cancer Institute in Milano activated a study in advanced malignant melanoma.5 The results were not impressive, with the exclusion of a small group of patients who had a limited disease and an interesting benefit from the treatment.
In those days Professor Cascinelli was head of the WHO melanoma working group. He offered me the opportunity to activate a global study in these low-grade melanoma patients to test the hypothesis of a clinical benefit.
Also in this case a protocol was quickly prepared, and the WHO scientific committee approved it. It became the WHO melanoma project 16.6 The study had a treatment period of two years and was placebo controlled, as in these patients after the surgical excision of the melanoma, no therapy is indicated. Interferon alfa was given on a weekly basis, at the very low dose of 3 MU, mainly to stimulate an immune response and also to ensure optimal patient compliance.
Survival curves started to diverge after one year of therapy, indicating a potential benefit for patients treated with interferon alfa. But after the second year, after treatment ended, the curves were again close to each other.
The potential role of interferon alfa in melanoma is still controversial. Some positive trials are immediately counterbalanced by negative studies. So, where is the issue?
In my opinion, interferon alfa may have a positive role in low-risk melanoma patients after surgery. But the low-dose treatment must be applied on a long-term basis, possibly for a life time. The initial benefits observed after one year should have time to consolidate year after year. And the application of a low weekly dose makes this therapeutic regimen feasible and acceptable to patients.
Unfortunately, no collaborative group has had the resources or willingness to test this hypothesis. It remains a possibility without a definite demonstration.
To conclude, let me add that planning and activating many studies with interferon alfa in oncology, in virology, in autoimmune diseases in the 1980s and 1990s has been a unique experience and a great achievement. Initial steps were clearly wrong: In those days investigators were greatly biased by the chemotherapy approach—the more the better. Interferon alfa, and then all newly discovered cytokines, taught us the lesson that the immune system must be activated by small doses and by continuous exposure.
1. A. Isaacs and J. Lindenmann, "Virus Interference. I. The Interferon," Proceedings of the Royal Society of London B: Biological Sciences, 147, 258-267 (1957).
2. J.R. Quesada, J. Reuben, J.T. Manning, E.M. Hersh, J.U. Gutterman, "Alpha Interferon for Induction of Remission in Hairy-Cell Leukemia," New England Journal of Medicine, 310, 15-18 (1984).
3. The Italian Cooperative Study Group on Chronic Myeloid Leukemia, Interferon Alfa-2a as Compared with Conventional Chemotherapy for the Treatment of Chronic Myeloid Leukemia," New England Journal of Medicine, 330, 820-825 (1994).
4. K. Strebhardt and A. Ullrich, "Another Look at Imatinib Mesylate," New England Journal of Medicine, 355, 2481-2482 (2006).
5. E. Bajetta, A. Di Leo, M. Zampino et al., "Multicenter Randomized Trial of Dacarbazine Alone or in Combination with Two Different Doses and Schedules of Interferon alfa-2a in the Treatment of Advanced Melanoma," from the Biological Response Modifier in Melanoma Italian Cooperative Group, Journal of Clinical Oncology, 12, 806-811 (1994).
6. N. Cascinelli, R. Bufalino, A. Morabito, R. MacKie, "Results of Adjuvant Interferon Study in WHO Melanoma Programme," Lancet, 343, 913-914 (1994).